Plants

2024

Jump to: 2023, 2022, 2021, 2020, 2019

16 pages, 2224 KiB

Open AccessArticle

Isolation and Selection of Protein-Rich Mutants of Chlorella vulgaris by Fluorescence-Activated Cell Sorting with Enhanced Biostimulant Activity to Germinate Garden Cress Seeds

by Mafalda Trovão, Lisa Schüler, Humberto Pedroso, Ana Reis, Gonçalo Espírito Santo, Ana Barros, Nádia Correia, Joana Ribeiro, Gabriel Bombo, Florinda Gama, Catarina Viana, Monya M. Costa, Sara Ferreira, Helena Cardoso, João Varela, Joana Silva, Filomena Freitas and Hugo Pereira

Plants 2024, 13(17), 2441; https://doi.org/10.3390/plants13172441 - 1 Sep 2024

Viewed by 1161

Abstract

Microalgae are a promising feedstock with proven biostimulant activity that is enhanced by their biochemical components (e.g., amino acids and phytohormones), which turns them into an appealing feedstock to reduce the use of fertilisers in agriculture and improve crop productivity and resilience. Thus, [...] Read more.

Microalgae are a promising feedstock with proven biostimulant activity that is enhanced by their biochemical components (e.g., amino acids and phytohormones), which turns them into an appealing feedstock to reduce the use of fertilisers in agriculture and improve crop productivity and resilience. Thus, this work aimed to isolate protein-rich microalgal mutants with increased biostimulant activity. Random mutagenesis was performed with Chlorella vulgaris, and a selection of protein-rich mutants were sorted through fluorescence-activated cell sorting (FACS), resulting in the isolation of 17 protein-rich mutant strains with protein contents 19–34% higher than that of the wildtype (WT). Furthermore, mutant F4 displayed a 38%, 22% and 62% higher biomass productivity, growth rate and chlorophyll content, respectively. This mutant was then scaled up to a 7 L benchtop reactor to produce biomass and evaluate the biostimulant potential of this novel strain towards garden cress seeds. Compared to water (control), the germination index and the relative total growth increased by 7% and 19%, respectively, after the application of 0.1 g L⁻¹ of this bioproduct, which highlights its biostimulant potential. Full article

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16 pages, 4106 KiB

Open AccessArticle

BBX Genes of Cymbidium ensifolium Exhibited Intense Response to Blue Light in Meristem Induction through Artificial Control

by Xiuming Chen, Muqi Niu, Xiaopei Wu, Yukun Peng, Ruiyue Zheng, Mengya Cheng, Kai Zhao, Yuzhen Zhou and Donghui Peng

Plants 2024, 13(17), 2375; https://doi.org/10.3390/plants13172375 - 26 Aug 2024

Viewed by 758

Abstract

Cymbidium ensifolium, a prominent orchid species, is both highly valued for its ornamental qualities and commercially cultivated. However, the species has a considerable challenge in its breeding efforts due to the lengthy period of 7–8 years required for it to transition from seed [...] Read more.

Cymbidium ensifolium, a prominent orchid species, is both highly valued for its ornamental qualities and commercially cultivated. However, the species has a considerable challenge in its breeding efforts due to the lengthy period of 7–8 years required for it to transition from seed germination to flowering. BBXs are multifunctional proteins that modulate the actions of critical regulators including HY5 and COP1 in response to blue light, ultimately impacting photomorphogenic processes. In this study, BBX proteins, known for their essential roles in regulating developmental processes under various light conditions, were chosen as the main subject of investigation. The outcome reveals the presence of 19 BBX genes in their genome. The genes are classified into four separate clades and dispersed among 12 out of the 20 chromosomes. Located in the nuclear, physicochemical properties of proteins, analysis of the promoter region reveals the existence of almost 800 cis-acting elements, highlighting the complex regulatory mechanisms that control the expression of the CeBBXs in various organs, as well as their response to light and hormone inputs. Moreover, the examination of differential expression under blue light therapy reveals their involvement in photomorphogenic reactions. The expression of CeBBXs exhibits substantial alterations as the duration of exposure to blue light increases. These findings contribute to a deeper understanding of the roles that BBX genes serve in C. ensifolium, providing a basis for future studies on the functions and regulatory mechanisms of BBX members in the context of floral initiation and development within this species. Full article

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23 pages, 5002 KiB

Open AccessArticle

Abscisic Acid Regulates the Occurrence and Recovery of the Striped Leaf Phenotype in Response to Lacking Light at the Base of Sheath in Rice by Modulating Carbohydrate Metabolism

by Jiasheng Chen, Shaowen Yang, Ming Fu, Ying He and Hanlai Zeng

Plants 2024, 13(15), 2090; https://doi.org/10.3390/plants13152090 - 28 Jul 2024

Viewed by 877

Abstract

Rice B03S mutants with intermittent leaf discoloration were developed from the photoperiod- and thermosensitive genic male sterile (PTGMS) rice line Efeng 1S. After these plants were deeply transplanted, the new leaves manifested typical stripe patterns. In this study, deep and shallow transplantation of [...] Read more.

Rice B03S mutants with intermittent leaf discoloration were developed from the photoperiod- and thermosensitive genic male sterile (PTGMS) rice line Efeng 1S. After these plants were deeply transplanted, the new leaves manifested typical stripe patterns. In this study, deep and shallow transplantation of B03S was carried out, and aluminum shading was performed directly on the leaf sheath. It was determined that the reason for the appearance of the striped leaf trait was that the base of leaf sheath lacked light, at which time the sheath transformed from the source organ to the sink organ in rice. To elucidate the related metabolic changes in glycometabolism and abscisic acid (ABA) biosynthesis and transcriptional regulation in the leaf sheath, ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) combined with transcriptome and real-time quantitative PCR (qPCR) validation were used for analysis after deep and shallow transplantation. The result indicates that the leaf sheath may need to compete with the new leaves for sucrose produced by the photosynthesis of old leaves in response to lacking light at the base of sheath. Moreover, the ABA content increases in the leaf sheath when the gene expression of ABA2 and AAO1 is upregulated at the same time, enhancing the plant’s resistance to the adverse condition of shading at the leaf sheath. Furthermore, exogenous spraying of B03S with ABA solution was carried out to help recovery under shading stress. The result indicates that the synthesis of endogenous ABA in the leaf sheath is reduced by spraying ABA. At the same time, ABA regulates sucrose metabolism by inhibiting the expression of the SUS gene. This allows for more sucrose synthesized by the old leaves to be transported to the new leaves, resulting an obvious recovery effect of the strip leaf character due to the re-balance of sugar supply and demand in B03S. These findings improve the understanding of the physiological function and metabolic mechanism of the rice leaf sheath, provide a theoretical basis for uneven leaf coloration in nature, and provide theoretical guidance for rice production via seedling transplantation or direct seeding. Full article

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18 pages, 14462 KiB

Open AccessArticle

Overexpression of RpKTI2 from Robinia pseudoacacia Affects the Photosynthetic Physiology and Endogenous Hormones of Tobacco

by Jian Zhou, Pengxiang Die, Songyan Zhang, Xiaoya Han, Chenguang Wang and Peipei Wang

Plants 2024, 13(13), 1867; https://doi.org/10.3390/plants13131867 - 6 Jul 2024

Viewed by 802

Abstract

Kunitz trypsin inhibitor genes play important roles in stress resistance. In this study, we investigated RpKTI2 cloned from Robinia pseudoacacia and its effect on tobacco. RpKTI2 was introduced into the tobacco cultivar NC89 using Agrobacterium-mediated transformation. Six RpKTI2-overexpressing lines were obtained. [...] Read more.

Kunitz trypsin inhibitor genes play important roles in stress resistance. In this study, we investigated RpKTI2 cloned from Robinia pseudoacacia and its effect on tobacco. RpKTI2 was introduced into the tobacco cultivar NC89 using Agrobacterium-mediated transformation. Six RpKTI2-overexpressing lines were obtained. Transgenic and wild-type tobacco plants were then compared for photosynthetic characteristics and endogenous hormone levels. Transgenic tobacco showed minor changes in chlorophyll content, fluorescence, and photosynthetic functions. However, the maximum photochemical efficiency (F_v/F_m) increased significantly while intercellular CO₂ concentration (C_i) decreased significantly. Stomatal size and hormone content (indole-3-acetic acid, zeatin riboside, gibberellin, and indole-3-propionic acid) were reduced, while brassinosteroid content increased. Random forest regression revealed that RpKTI2 overexpression had the biggest impact on carotenoid content, initial fluorescence, C_i, stomatal area, and indole-3-acetic acid. Overall, RpKTI2 overexpression minimally affected chlorophyll synthesis and photosynthetic system characteristics but influenced stomatal development and likely enhanced the antioxidant capacity of tobacco. These findings provide a basis for future in-depth research on RpKTI2. Full article

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18 pages, 1411 KiB

Open AccessArticle

Management of Secondary Metabolite Synthesis and Biomass in Basil (Ocimum basilicum L.) Microgreens Using Different Continuous-Spectrum LED Lights

by Mohammad Reza Fayezizadeh, Naser Alemzadeh Ansari, Mohammad Mahmoodi Sourestani, Masayuki Fujita and Mirza Hasanuzzaman

Plants 2024, 13(10), 1394; https://doi.org/10.3390/plants13101394 - 17 May 2024

Cited by 2 | Viewed by 1138

Abstract

Different LED light spectra (LS) are absorbed by different plant photoreceptors and can control biomass and plant secondary metabolite synthesis. In this study, the effects of continuous-spectrum LED lights (red, blue, white, red + blue, and 12 h blue + 12 h red) [...] Read more.

Different LED light spectra (LS) are absorbed by different plant photoreceptors and can control biomass and plant secondary metabolite synthesis. In this study, the effects of continuous-spectrum LED lights (red, blue, white, red + blue, and 12 h blue + 12 h red) on the production value, antioxidant compounds, and biomass of basil (Ocimum basilicum L.) microgreens (Red Rubin, Violeto, and Kapoor cultivars and the Ablagh genotype) were investigated. The results showed significant effects of LS on cultivar (Cv) and the interaction of LS and Cv on the studied traits. The highest quantitys of chlorophyll a, total chlorophyll, and nitrate were obtained in Violeto under blue lighting. Red lighting enhanced starch synthesis in Red Rubin and flavonoids in the Violeto Cv. The highest biomass (4.54 kg m⁻²) was observed in the Ablagh genotype and the highest carbohydrate synthesis in Violeto Cv in the red + blue treatment. The highest anthocyanin content (26.33 mg 100 g⁻¹ FW) was observed for Red Rubin Cv under 12 h blue + 12 h red light. The greatest antioxidant capacity (83.57% inhibition), the highest levels of phenolic compounds (2027.25 mg GA 100 g⁻¹ FW), vitamin C (405.76 mg 100 g⁻¹ FW), proline, antioxidant potential composite index (APCI), and the greatest production values were obtained for the Ablagh genotype under blue lighting. Taken together, the experiment findings indicate that growing the Ablagh genotype under continuous blue lighting can increase the antioxidant capacity, phenolic compounds, and vitamin C and that this LED light spectrum can be used as a practical method to produce basil microgreens with high nutritional health value. Full article

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17 pages, 2862 KiB

Open AccessArticle

Nitrogen Nutrition Modulates the Response to Alternaria brassicicola Infection via Metabolic Modifications in Arabidopsis Seedlings

by Thibault Barrit, Elisabeth Planchet, Jérémy Lothier, Pascale Satour, Sophie Aligon, Guillaume Tcherkez, Anis M. Limami, Claire Campion and Béatrice Teulat

Plants 2024, 13(4), 534; https://doi.org/10.3390/plants13040534 - 15 Feb 2024

Viewed by 1270

Abstract

Little is known about the effect of nitrogen nutrition on seedling susceptibility to seed-borne pathogens. We have previously shown that seedlings grown under high nitrate (5 mM) conditions are less susceptible than those grown under low nitrate (0.1 mM) and ammonium (5 mM) [...] Read more.

Little is known about the effect of nitrogen nutrition on seedling susceptibility to seed-borne pathogens. We have previously shown that seedlings grown under high nitrate (5 mM) conditions are less susceptible than those grown under low nitrate (0.1 mM) and ammonium (5 mM) in the Arabidopsis-Alternaria brassicicola pathosystem. However, it is not known how seedling metabolism is modulated by nitrogen nutrition, nor what is its response to pathogen infection. Here, we addressed this question using the same pathosystem and nutritive conditions, examining germination kinetics, seedling development, but also shoot ion contents, metabolome, and selected gene expression. Nitrogen nutrition clearly altered the seedling metabolome. A similar metabolomic profile was observed in inoculated seedlings grown at high nitrate levels and in not inoculated-seedlings. High nitrate levels also led to specific gene expression patterns (e.g., polyamine metabolism), while other genes responded to inoculation regardless of nitrogen supply conditions. Furthermore, the metabolites best correlated with high disease symptoms were coumarate, tyrosine, hemicellulose sugars, and polyamines, and those associated with low symptoms were organic acids (tricarboxylic acid pathway, glycerate, shikimate), sugars derivatives and β-alanine. Overall, our results suggest that the beneficial effect of high nitrate nutrition on seedling susceptibility is likely due to nutritive and signaling mechanisms affecting developmental plant processes detrimental to the pathogen. In particular, it may be due to a constitutively high tryptophan metabolism, as well as down regulation of oxidative stress caused by polyamine catabolism. Full article

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2023

Jump to: 2024, 2022, 2021, 2020, 2019

25 pages, 3500 KiB

Open AccessArticle

Origin and Function of Amino Acids in Nectar and Nectaries of Pitcairnia Species with Particular Emphasis on Alanine and Glutamine

by Thomas Göttlinger and Gertrud Lohaus

Plants 2024, 13(1), 23; https://doi.org/10.3390/plants13010023 - 20 Dec 2023

Viewed by 1721

Abstract

Floral nectar contains sugars and numerous other compounds, including amino acids, but little is known about their function and origin in nectar. Therefore, the amino acid, sugar, and inorganic ion concentrations, as well as the activity of alanine aminotransferase (AlaAT) and glutamine synthetase [...] Read more.

Floral nectar contains sugars and numerous other compounds, including amino acids, but little is known about their function and origin in nectar. Therefore, the amino acid, sugar, and inorganic ion concentrations, as well as the activity of alanine aminotransferase (AlaAT) and glutamine synthetase (GS) in nectar, nectaries, and leaves were analyzed in 30 Pitcairnia species. These data were compared with various floral traits, the pollinator type, and the phylogenetic relationships of the species to find possible causes for the high amino acid concentrations in the nectar of some species. The highest concentrations of amino acids (especially alanine) in nectar were found in species with reddish flowers. Furthermore, the concentration of amino acids in nectar and nectaries is determined through analyzing flower color/pollination type rather than phylogenetic relations. This study provides new insights into the origin of amino acids in nectar. The presence of almost all amino acids in nectar is mainly due to their transport in the phloem to the nectaries, with the exception of alanine, which is partially produced in nectaries. In addition, active regulatory mechanisms are required in nectaries that retain most of the amino acids and allow the selective secretion of specific amino acids, such as alanine. Full article

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17 pages, 8067 KiB

Open AccessArticle

Differential Responses of Medicago truncatula NLA Homologs to Nutrient Deficiency and Arbuscular Mycorrhizal Symbiosis

by Wei-Yi Lin, Hsin-Ni Yang, Chen-Yun Hsieh and Chen Deng

Plants 2023, 12(24), 4129; https://doi.org/10.3390/plants12244129 - 11 Dec 2023

Viewed by 1284

Abstract

NITROGEN LIMITATION ADAPTATION (NLA), a plasma-membrane-associated ubiquitin E3 ligase, plays a negative role in the control of the phosphate transporter family 1 (PHT1) members in Arabidopsis and rice. There are three NLA homologs in the Medicago truncatula genome, but it has been unclear [...] Read more.

NITROGEN LIMITATION ADAPTATION (NLA), a plasma-membrane-associated ubiquitin E3 ligase, plays a negative role in the control of the phosphate transporter family 1 (PHT1) members in Arabidopsis and rice. There are three NLA homologs in the Medicago truncatula genome, but it has been unclear whether the function of these homologs is conserved in legumes. Here we investigated the subcellular localization and the responses of MtNLAs to external phosphate and nitrate status. Similar to AtNLA1, MtNLA1/MtNLA2 was localized in the plasma membrane and nucleus. MtNLA3 has three alternative splicing variants, and intriguingly, MtNLA3.1, the dominant variant, was not able to target the plasma membrane, whereas MtNLA3.2 and MtNLA3.3 were capable of associating with the plasma membrane. In contrast with AtNLA1, we found that MtNLAs were not affected or even upregulated by low-phosphate treatment. We also found that MtNLA3 was upregulated by arbuscular mycorrhizal (AM) symbiosis, and overexpressing MtNLA3.1 in Medicago roots resulted in a decrease in the transcription levels of STR, an essential gene for arbuscule development. Taken together, our results highlight the difference between MtNLA homologs and AtNLA1. Further characterization will be required to reveal the regulation of these genes and their roles in the responses to external nutrient status and AM symbiosis. Full article

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16 pages, 2935 KiB

Open AccessArticle

Arabidopsis Root Development Regulation by the Endogenous Folate Precursor, Para-Aminobenzoic Acid, via Modulation of the Root Cell Cycle

by Hanna Lasok, Hugues Nziengui, Philip Kochersperger and Franck Anicet Ditengou

Plants 2023, 12(24), 4076; https://doi.org/10.3390/plants12244076 - 5 Dec 2023

Cited by 2 | Viewed by 1574

Abstract

The continuous growth of roots depends on their ability to maintain a balanced ratio between cell production and cell differentiation at the tip. This process is regulated by the hormonal balance of cytokinin and auxin. However, other important regulators, such as plant folates, [...] Read more.

The continuous growth of roots depends on their ability to maintain a balanced ratio between cell production and cell differentiation at the tip. This process is regulated by the hormonal balance of cytokinin and auxin. However, other important regulators, such as plant folates, also play a regulatory role. In this study, we investigated the impact of the folate precursor para-aminobenzoic acid (PABA) on root development. Using pharmacological, genetic, and imaging approaches, we show that the growth of Arabidopsis thaliana roots is repressed by either supplementing the growth medium with PABA or overexpressing the PABA synthesis gene GAT-ADCS. This is associated with a smaller root meristem consisting of fewer cells. Conversely, reducing the levels of free root endogenous PABA results in longer roots with extended meristems. We provide evidence that PABA represses Arabidopsis root growth in a folate-independent manner and likely acts through two mechanisms: (i) the G2/M transition of cell division in the root apical meristem and (ii) promoting premature cell differentiation in the transition zone. These data collectively suggest that PABA plays a role in Arabidopsis root growth at the intersection between cell division and cell differentiation. Full article

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52 pages, 4656 KiB

Open AccessEditor’s ChoiceReview

A Travel through Landscapes of Seed Dormancy

by Alberto Gianinetti

Plants 2023, 12(23), 3963; https://doi.org/10.3390/plants12233963 - 24 Nov 2023

Cited by 3 | Viewed by 3092

Abstract

Basic features of seed dormancy are illustrated. The seed overall regulatory network governs seed metabolism and development, and it is coordinated by plant hormones. A functional model focused on abscisic acid (ABA), the foremost plant hormone in dormancy, is used as a framework [...] Read more.

Basic features of seed dormancy are illustrated. The seed overall regulatory network governs seed metabolism and development, and it is coordinated by plant hormones. A functional model focused on abscisic acid (ABA), the foremost plant hormone in dormancy, is used as a framework to critically discuss the literature. Gibberellins (GAs) have a main role in germination, and the ABA–GAs balance is a typical feature of the seed state: ABA dominates during dormancy and GAs prevail through germination. Thus, the literature converges toward envisaging the development switch between dormancy and germination as represented by the ABA/GAs ratio. The ABA–GAs antagonism is based on mutual inhibition, a feature of the regulatory network architecture that characterizes development trajectories based on a regulatory circuit with a bistable switch. Properties of such kind of regulatory architecture are introduced step by step, and it is shown that seed development—toward either dormancy or germination—is more properly represented by a tristable regulatory circuit, whose intermediate metastable states ultimately take one or the other development trajectory. Although the ABA/GAs ratio can conveniently represent the state of the seed overall regulatory network along the seed development trajectory, specific (unknown) dormancy factors are required to determine the development trajectory. The development landscape is shown to provide a well-suited representation of seed states travelling along developmental trajectories, particularly when the states are envisioned as regulatory circuits. Looking at seed dormancy in terms of regulatory circuits and development landscapes offers a valuable perspective to improve our understanding of this biological phenomenon. Full article

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19 pages, 1444 KiB

Open AccessArticle

Seasonal Variation in Cell Wall Composition and Carbohydrate Metabolism in the Seagrass Posidonia oceanica Growing at Different Depths

by Marwa Ismael, Quentin Charras, Maïté Leschevin, Damien Herfurth, Romain Roulard, Anthony Quéro, Christine Rusterucci, Jean-Marc Domon, Colette Jungas, Wilfred Vermerris and Catherine Rayon

Plants 2023, 12(17), 3155; https://doi.org/10.3390/plants12173155 - 1 Sep 2023

Cited by 1 | Viewed by 1428

Abstract

Posidonia oceanica is a common seagrass in the Mediterranean Sea that is able to sequester large amounts of carbon. The carbon assimilated during photosynthesis can be partitioned into non-structural sugars and cell-wall polymers. In this study, we investigated the distribution of carbon in [...] Read more.

Posidonia oceanica is a common seagrass in the Mediterranean Sea that is able to sequester large amounts of carbon. The carbon assimilated during photosynthesis can be partitioned into non-structural sugars and cell-wall polymers. In this study, we investigated the distribution of carbon in starch, soluble carbohydrates and cell-wall polymers in leaves and rhizomes of P. oceanica. Analyses were performed during summer and winter in meadows located south of the Frioul archipelago near Marseille, France. The leaves and rhizomes were isolated from plants collected in shallow (2 m) and deep water (26 m). Our results showed that P. oceanica stores more carbon as starch, sucrose and cellulose in summer and that this is more pronounced in rhizomes from deep-water plants. In winter, the reduction in photoassimilates was correlated with a lower cellulose content, compensated with a greater lignin content, except in rhizomes from deep-water plants. The syringyl-to-guaiacyl (S/G) ratio in the lignin was higher in leaves than in rhizomes and decreased in rhizomes in winter, indicating a change in the distribution or structure of the lignin. These combined data show that deep-water plants store more carbon during summer, while in winter the shallow- and deep-water plants displayed a different cell wall composition reflecting their environment. Full article

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31 pages, 5290 KiB

Open AccessArticle

Responses to Airborne Ozone and Soilborne Metal Pollution in Afforestation Plants with Different Life Forms

by Madeleine S. Günthardt-Goerg, Rodolphe Schläpfer and Pierre Vollenweider

Plants 2023, 12(16), 3011; https://doi.org/10.3390/plants12163011 - 21 Aug 2023

Cited by 1 | Viewed by 1563

Abstract

With the current increases in environmental stress, understanding species-specific responses to multiple stress agents is needed. This science is especially important for managing ecosystems that are already confronted with considerable pollution. In this study, responses to ozone (O3, ambient daily course values + [...] Read more.

With the current increases in environmental stress, understanding species-specific responses to multiple stress agents is needed. This science is especially important for managing ecosystems that are already confronted with considerable pollution. In this study, responses to ozone (O3, ambient daily course values + 20 ppb) and mixed metal contamination in soils (MC, cadmium/copper/lead/zinc = 25/1100/2500/1600 mg kg⁻¹), separately and in combination, were evaluated for three plant species (Picea abies, Acer pseudoplatanus, Tanacetum vulgare) with different life forms and ecological strategies. The two treatments elicited similar stress reactions, as shown by leaf functional traits, gas exchange, tannin, and nutrient markers, irrespective of the plant species and life form, whereas the reactions to the treatments differed in magnitude. Visible and microscopic injuries at the organ or cell level appeared along the penetration route of ozone and metal contamination. At the whole plant level, the MC treatment caused more severe injuries than the O3 treatment and few interactions were observed between the two stress factors. Picea trees, with a slow-return strategy, showed the highest stress tolerance in apparent relation to an enhancement of conservative traits and an exclusion of stress agents. The ruderal and more acquisitive Tanacetum forbs translocated large amounts of contaminants above ground, which may be of concern in a phytostabilisation context. The deciduous Acer trees—also with an acquisitive strategy—were most sensitive to both stress factors. Hence, species with slow-return strategies may be of particular interest for managing metal-polluted sites in the current context of multiple stressors and for safely confining soil contaminants below ground. Full article

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17 pages, 3174 KiB

Open AccessArticle

Heterologous Overexpression of Apple MdKING1 Promotes Fruit Ripening in Tomato

by Qianyu Yue, Xinyue Yang, Pengda Cheng, Jieqiang He, Wenyun Shen, Yixuan Li, Fengwang Ma, Chundong Niu and Qingmei Guan

Plants 2023, 12(15), 2848; https://doi.org/10.3390/plants12152848 - 2 Aug 2023

Cited by 2 | Viewed by 1731

Abstract

Fruit ripening is governed by a complex regulatory network, and ethylene plays an important role in this process. MdKING1 is a γ subunit of SNF1-related protein kinases (SnRKs), but the function was unclear. Here, we characterized the role of MdKING1 during fruit ripening, [...] Read more.

Fruit ripening is governed by a complex regulatory network, and ethylene plays an important role in this process. MdKING1 is a γ subunit of SNF1-related protein kinases (SnRKs), but the function was unclear. Here, we characterized the role of MdKING1 during fruit ripening, which can promote fruit ripening through the ethylene pathway. Our findings reveal that MdKING1 has higher expression in early-ripening cultivars than late-ripening during the early stage of apple fruit development, and its transcription level significantly increased during apple fruit ripening. Overexpression of MdKING1 (MdKING1 OE) in tomatoes could promote early ripening of fruits, with the increase in ethylene content and the loss of fruit firmness. Ethylene inhibitor treatment could delay the fruit ripening of both MdKING1 OE and WT fruits. However, MdKING1 OE fruits turned fruit ripe faster, with an increase in carotenoid content compared with WT. In addition, the expression of genes involved in ethylene biosynthesis (SlACO1, SlACS2, and SlACS4), carotenoid biosynthesis (SlPSY1 and SlGgpps2a), and fruit firmness regulation (SlPG2a, SlPL, and SlCEL2) was also increased in the fruits of MdKING1 OE plants. In conclusion, our results suggest that MdKING1 plays a key role in promoting tomato fruit ripening, thus providing a theoretical basis for apple fruit quality improvement by genetic engineering in the future. Full article

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20 pages, 7144 KiB

Open AccessArticle

Transcriptomics and Metabolomics Reveal the Critical Genes of Carotenoid Biosynthesis and Color Formation of Goji (Lycium barbarum L.) Fruit Ripening

by Feng Wei, Ru Wan, Zhigang Shi, Wenli Ma, Hao Wang, Yongwei Chen, Jianhua Bo, Yunxiang Li, Wei An, Ken Qin and Youlong Cao

Plants 2023, 12(15), 2791; https://doi.org/10.3390/plants12152791 - 27 Jul 2023

Cited by 3 | Viewed by 1533

Abstract

Carotenoids in goji (Lycium barbarum L.) have excellent health benefits, but the underlying mechanism of carotenoid synthesis and color formation in goji fruit ripening is still unclear. The present study uses transcriptomics and metabolomics to investigate carotenoid biosynthesis and color formation differences [...] Read more.

Carotenoids in goji (Lycium barbarum L.) have excellent health benefits, but the underlying mechanism of carotenoid synthesis and color formation in goji fruit ripening is still unclear. The present study uses transcriptomics and metabolomics to investigate carotenoid biosynthesis and color formation differences in N1 (red fruit) and N1Y (yellow fruit) at three stages of ripening. Twenty-seven carotenoids were identified in N1 and N1Y fruits during the M1, M2, and M3 periods, with the M2 and M3 periods being critical for the difference in carotenoid and color between N1 and N1Y fruit. Weighted gene co-expression network analysis (WGCNA), gene trend analysis, and correlation analysis suggest that PSY1 and ZDS16 may be important players in the synthesis of carotenoids during goji fruit ripening. Meanwhile, 63 transcription factors (TFs) were identified related to goji fruit carotenoid biosynthesis. Among them, four TFs (CMB1-1, WRKY22-1, WRKY22-3, and RAP2-13-like) may have potential regulatory relationships with PSY1 and ZDS16. This work sheds light on the molecular network of carotenoid synthesis and explains the differences in carotenoid accumulation in different colored goji fruits. Full article

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16 pages, 2792 KiB

Open AccessArticle

Photosynthesis in the Biomass Model Species Lemna minor Displays Plant-Conserved and Species-Specific Features

by Monique Liebers, Elisabeth Hommel, Björn Grübler, Jakob Danehl, Sascha Offermann and Thomas Pfannschmidt

Plants 2023, 12(13), 2442; https://doi.org/10.3390/plants12132442 - 25 Jun 2023

Cited by 1 | Viewed by 2448

Abstract

Lemnaceae are small freshwater plants with extraordinary high growth rates. We aimed to test whether this correlates with a more efficient photosynthesis, the primary energy source for growth. To this end, we compared photosynthesis properties of the duckweed Lemna minor and the terrestrial [...] Read more.

Lemnaceae are small freshwater plants with extraordinary high growth rates. We aimed to test whether this correlates with a more efficient photosynthesis, the primary energy source for growth. To this end, we compared photosynthesis properties of the duckweed Lemna minor and the terrestrial model plant Arabidopsis thaliana. Chlorophyll fluorescence analyses revealed high similarity in principle photosynthesis characteristics; however, Lemna exhibited a more effective light energy transfer into photochemistry and more stable photosynthesis parameters especially under high light intensities. Western immunoblot analyses of representative photosynthesis proteins suggested potential post-translational modifications in Lemna proteins that are possibly connected to this. Phospho-threonine phosphorylation patterns of thylakoid membrane proteins displayed a few differences between the two species. However, phosphorylation-dependent processes in Lemna such as photosystem II antenna association and the recovery from high-light-induced photoinhibition were not different from responses known from terrestrial plants. We thus hypothesize that molecular differences in Lemna photosynthesis proteins are associated with yet unidentified mechanisms that improve photosynthesis and growth efficiencies. We also developed a high-magnification video imaging approach for Lemna multiplication which is useful to assess the impact of external factors on Lemna photosynthesis and growth. Full article

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10 pages, 1016 KiB

Open AccessArticle

Best Procedures for Leaf and Stem Water Potential Measurements in Grapevine: Cultivar and Water Status Matter

by Martina Tomasella, Alberto Calderan, Alenka Mihelčič, Francesco Petruzzellis, Riccardo Braidotti, Sara Natale, Klemen Lisjak, Paolo Sivilotti and Andrea Nardini

Plants 2023, 12(13), 2412; https://doi.org/10.3390/plants12132412 - 22 Jun 2023

Cited by 5 | Viewed by 2373

Abstract

The pressure chamber is the most used tool for plant water status monitoring. However, species/cultivar and seasonal effects on protocols for reliable water potential determination have not been properly tested. In four grapevine cultivars and two times of the season (early season, Es; [...] Read more.

The pressure chamber is the most used tool for plant water status monitoring. However, species/cultivar and seasonal effects on protocols for reliable water potential determination have not been properly tested. In four grapevine cultivars and two times of the season (early season, Es; late season, Ls, under moderate drought), we assessed the maximum sample storage time before leaf water potential (Ψ_leaf) measurements and the minimum equilibration time for stem water potential (Ψ_stem) determination, taking 24 h leaf cover as control. In ‘Pinot gris’, Ψ_leaf already decreased after 1 h leaf storage in both campaigns, dropping by 0.4/0.5 MPa after 3 h, while in ‘Refosk’, it decreased by 0.1 MPa after 1 and 2 h in Es and Ls, respectively. In ‘Merlot’ and ‘Merlot Kanthus’, even 3 h storage did not affect Ψ_leaf. In Es, the minimum Ψ_stem equilibration was 1 h for ‘Refošk’ and 10 min for ‘Pinot gris’ and ‘Merlot’. In Ls, ‘Merlot Kanthus’ required more than 2 h equilibration, while 1 h to 10 min was sufficient for the other cultivars. The observed cultivar and seasonal differences indicate that the proposed tests should be routinely performed prior to experiments to define ad hoc procedures for water status determination. Full article

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31 pages, 6496 KiB

Open AccessArticle

Multi-Omics Analysis of Vicia cracca Responses to Chronic Radiation Exposure in the Chernobyl Exclusion Zone

by Viktoria Voronezhskaya, Polina Volkova, Sofia Bitarishvili, Ekaterina Shesterikova, Mikhail Podlutskii, Gilles Clement, Christian Meyer, Gustavo Turqueto Duarte, Maksim Kudin, Dmitrii Garbaruk, Larisa Turchin and Elizaveta Kazakova

Plants 2023, 12(12), 2318; https://doi.org/10.3390/plants12122318 - 14 Jun 2023

Cited by 3 | Viewed by 2096

Abstract

Our understanding of the long-term consequences of chronic ionising radiation for living organisms remains scarce. Modern molecular biology techniques are helpful tools for researching pollutant effects on biota. To reveal the molecular phenotype of plants growing under chronic radiation exposure, we sampled Vicia [...] Read more.

Our understanding of the long-term consequences of chronic ionising radiation for living organisms remains scarce. Modern molecular biology techniques are helpful tools for researching pollutant effects on biota. To reveal the molecular phenotype of plants growing under chronic radiation exposure, we sampled Vicia cracca L. plants in the Chernobyl exclusion zone and areas with normal radiation backgrounds. We performed a detailed analysis of soil and gene expression patterns and conducted coordinated multi-omics analyses of plant samples, including transcriptomics, proteomics, and metabolomics. Plants growing under chronic radiation exposure showed complex and multidirectional biological effects, including significant alterations in the metabolism and gene expression patterns of irradiated plants. We revealed profound changes in carbon metabolism, nitrogen reallocation, and photosynthesis. These plants showed signs of DNA damage, redox imbalance, and stress responses. The upregulation of histones, chaperones, peroxidases, and secondary metabolism was noted. Full article

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13 pages, 3779 KiB

Open AccessArticle

Development and Biomechanics of Grewia lasiocarpa E. Mey. Ex Harv. Trichomes Exudate

by Nneka Augustina Akwu, Yougasphree Naidoo, Moganavelli Singh, Yaser Hassan Dewir, Katalin Magyar-Tábori, Makhotso Lekhooa and Adeyemi Oladapo Aremu

Plants 2023, 12(11), 2198; https://doi.org/10.3390/plants12112198 - 1 Jun 2023

Cited by 1 | Viewed by 1916

Abstract

Grewia lasiocarpa E. Mey. Ex Harv., Malvaceae (forest raisin) is a tropical small tree or shrub valued for its ecological importance as well as its nutritional, antioxidant, antibacterial, and anti-cancer properties as well as its ecological and ornamental importance. Glandular and non-glandular trichomes are [...] Read more.

Grewia lasiocarpa E. Mey. Ex Harv., Malvaceae (forest raisin) is a tropical small tree or shrub valued for its ecological importance as well as its nutritional, antioxidant, antibacterial, and anti-cancer properties as well as its ecological and ornamental importance. Glandular and non-glandular trichomes are present on the fruits, stem bark and leaves of G. lasiocarpa and these trichomes are the first line of defense. They are important structures that plants use to combat biotic and abiotic stress. The development of G. lasiocarpa trichomes and the biomechanics of the exudates present in the glandular (capitate) trichome were investigated for the first time using advanced microscopy techniques [Scanning electron microscope (SEM) and Transmission electron microscope (TEM)]. The pressurized cuticular striations may play a role in the exudates’ biomechanics, i.e., releasing secondary metabolites present in the capitate trichome, which was observed to be multidirectional. The presence of many glandular trichomes on a plant implies an increase in the amount of phytometabolites. A common precursor for the development of trichomes (non-glandular and glandular) was observed to be DNA synthesis associated with a periclinal cell division, thus the final fate of the cell is determined by cell cycle regulation, polarity, and expansion. The glandular trichomes of G. lasiocarpa are multicellular and polyglandular, while the non-glandular (glandless) trichomes are either single-celled or multicellular. Since, trichomes ‘house’ phytocompounds of medicinal, nutritional, and agronomical benefits; the molecular and genetic study of the glandular trichomes of Grewia lasiocarpa will be beneficial to humanity. Full article

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17 pages, 1400 KiB

Open AccessArticle

Coastal Halophytes: Potent Source of Bioactive Molecules from Saline Environment

by Milan Stanković, Zorica Stojanović-Radić, Dragana Jakovljević, Nenad Zlatić, Milica Luković and Zora Dajić-Stevanović

Plants 2023, 12(9), 1857; https://doi.org/10.3390/plants12091857 - 30 Apr 2023

Cited by 3 | Viewed by 1956

Abstract

This study represents a comparative analysis of secondary metabolites content, antioxidant, and antimicrobial activity of 24 halophytes from coastal saline habitats of the Balkan Peninsula (Montenegro, Albania, and Greece). Total content of phenolics, flavonoids, tannins, anthocyanins, antioxidant, and antimicrobial activity was determined for [...] Read more.

This study represents a comparative analysis of secondary metabolites content, antioxidant, and antimicrobial activity of 24 halophytes from coastal saline habitats of the Balkan Peninsula (Montenegro, Albania, and Greece). Total content of phenolics, flavonoids, tannins, anthocyanins, antioxidant, and antimicrobial activity was determined for dry methanolic (DME) and crude water extracts (CWE) and compared with well-known medicinal plants. The total phenolic content ranged from 13.23 to 376.08 mg of GA/g of DME, and from 33.68 to 511.10 mg/mL of CWE. The content of flavonoids ranged from 12.63 to 77.36 mg of RU/g of DME, and from 12.13 to 26.35 mg/mL of CWE. Total tannins and anthocyanins varied from 0.05 to 2.44 mg/mL, and from 1.31 to 39.81 µg/L, respectively. The antioxidant activity ranged from 1147.68 to 15.02 µg/mL for DME and from 1613.05 to 21.96 µg/mL for CWE. The best antioxidant properties, and the highest content of phenolic compounds, were determined for Polygonum maritimum and Limonium vulgare with values similar to or higher compared to the medicinal plants. Halophytes with significant antimicrobial potential were Limonium vulgare, L. angustifolium, and Artemisia maritima. Some of the analyzed coastal halophytes can be considered rich natural sources of phenolic compounds, with favorable antioxidative and antimicrobial properties. Full article

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11 pages, 1899 KiB

Open AccessFeature PaperArticle

Cytoplasmic Kinase Network Mediates Defense Response to Spodoptera litura in Arabidopsis

by Yoshitake Desaki, Minami Morishima, Yuka Sano, Takuya Uemura, Ayaka Ito, Keiichirou Nemoto, Akira Nozawa, Tatsuya Sawasaki and Gen-ichiro Arimura

Plants 2023, 12(9), 1747; https://doi.org/10.3390/plants12091747 - 24 Apr 2023

Cited by 4 | Viewed by 1774

Abstract

Plants defend against folivores by responding to folivore-derived elicitors following activation of signaling cascade networks. In Arabidopsis, HAK1, a receptor-like kinase, responds to polysaccharide elicitors (Frα) that are present in oral secretions of Spodoptera litura larvae to upregulate defense genes (e.g., PDF1.2) [...] Read more.

Plants defend against folivores by responding to folivore-derived elicitors following activation of signaling cascade networks. In Arabidopsis, HAK1, a receptor-like kinase, responds to polysaccharide elicitors (Frα) that are present in oral secretions of Spodoptera litura larvae to upregulate defense genes (e.g., PDF1.2) mediated through downstream cytoplasmic kinase PBL27. Here, we explored whether other protein kinases, including CPKs and CRKs, function with PBL27 in the intracellular signaling network for anti-herbivore responses. We showed that CRK2 and CRK3 were found to interact with PBL27, but CPKs did not. Although transcripts of PDF1.2 were upregulated in leaves of wild-type Arabidopsis plants in response to mechanical damage with Frα, this failed in CRK2- and PBL27-deficient mutant plants, indicating that the CRK2/PBL27 system is predominantly responsible for the Frα-responsive transcription of PDF1.2 in S. litura-damaged plants. In addition to CRK2-phosphorylated ERF13, as shown previously, ethylene signaling in connection to CRK2-phosphorylated PBL27 was predicted to be responsible for transcriptional regulation of a gene for ethylene response factor 13 (ERF13). Taken together, these findings show that CRK2 regulates not only ERF13 phosphorylation but also PBL27-dependent de novo synthesis of ERF13, thus determining active defense traits against S. litura larvae via transcriptional regulation of PDF1.2. Full article

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14 pages, 17795 KiB

Open AccessArticle

The Paeonia qiui R2R3-MYB Transcription Factor PqMYBF1 Positively Regulates Flavonol Accumulation

by Yue Zhang, Jingjing Duan, Qiaoyun Wang, Min Zhang, Hui Zhi, Zhangzhen Bai, Yanlong Zhang and Jianrang Luo

Plants 2023, 12(7), 1427; https://doi.org/10.3390/plants12071427 - 23 Mar 2023

Cited by 6 | Viewed by 1975

Abstract

Tree peony is a “spring colored-leaf” plant which has red leaves in early spring, and the red color of the leaves usually fades in late spring. Flavonols are one subgroup of flavonoids, and they affect the plant organs’ color as co-pigments of anthocyanins. [...] Read more.

Tree peony is a “spring colored-leaf” plant which has red leaves in early spring, and the red color of the leaves usually fades in late spring. Flavonols are one subgroup of flavonoids, and they affect the plant organs’ color as co-pigments of anthocyanins. To investigate the color variation mechanism of leaves in tree peony, PqMYBF1, one flavonol biosynthesis-related MYB gene was isolated from Paeonia qiui and characterized. PqMYBF1 contained the SG7 and SG7-2 motifs which are unique in flavonol-specific MYB regulators. Subcellular localization and transactivation assay showed that PqMYBF1 localized to the nucleus and acted as a transcriptional activator. The ectopic expression of PqMYBF1 in transgenic tobacco caused an observable increase in flavonol level and the anthocyanin accumulation was decreased significantly, resulting in pale pink flowers. Dual-luciferase reporter assays showed that PqMYBF1 could activate the promoters of PqCHS, PqF3H, and PqFLS. These results suggested that PqMYBF1 could promote flavonol biosynthesis by activating PqCHS, PqF3H, and PqFLS expression, which leads metabolic flux from anthocyanin to flavonol pathway, resulting in more flavonol accumulation. These findings provide a new train of thought for the molecular mechanism of leaf color variation in tree peony in spring, which will be helpful for the molecular breeding of tree peony with colored foliage. Full article

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34 pages, 4238 KiB

Open AccessEditor’s ChoiceReview

Water Content of Plant Tissues: So Simple That Almost Forgotten?

by Gederts Ievinsh

Plants 2023, 12(6), 1238; https://doi.org/10.3390/plants12061238 - 8 Mar 2023

Cited by 25 | Viewed by 13755

Abstract

The aim of the present review was to reconsider basic information about various functional aspects related to plant water content and provide evidence that the usefulness of measuring absolute water content in plant sciences is undervalued. First, general questions about water status in [...] Read more.

The aim of the present review was to reconsider basic information about various functional aspects related to plant water content and provide evidence that the usefulness of measuring absolute water content in plant sciences is undervalued. First, general questions about water status in plants as well as methods for determining water content and their associated problems were discussed. After a brief overview of the structural organization of water in plant tissues, attention was paid to the water content of different parts of plants. Looking at the influence of environmental factors on plant water status, the differences caused by air humidity, mineral supply, biotic effects, salinity, and specific life forms (clonal and succulent plants) were analyzed. Finally, it was concluded that the expression of absolute water content on a dry biomass basis makes easily noticeable functional sense, but the physiological meaning and ecological significance of the drastic differences in plant water content need to be further elucidated. Full article

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Graphical abstract

16 pages, 2730 KiB

Open AccessFeature PaperArticle

Comprehensive Ecotoxicity Studies on Quaternary Ammonium Salts Synthesized from Vitamin B₃ Supported by QSAR Calculations

by Aleksandra Nowacka, Adriana Olejniczak, Witold Stachowiak and Michał Niemczak

Plants 2023, 12(4), 914; https://doi.org/10.3390/plants12040914 - 17 Feb 2023

Cited by 2 | Viewed by 1782

Abstract

Lately, ionic forms (namely, quaternary ammonium salts, QASs) of nicotinamide, widely known as vitamin B₃, are gaining popularity in the sectors developing novel pharmaceuticals and agrochemicals. However, the direct influence of these unique QASs on the development of various terrestrial plants, [...] Read more.

Lately, ionic forms (namely, quaternary ammonium salts, QASs) of nicotinamide, widely known as vitamin B₃, are gaining popularity in the sectors developing novel pharmaceuticals and agrochemicals. However, the direct influence of these unique QASs on the development of various terrestrial plants, as well as other organisms, remains unknown. Therefore, three compounds comprising short, medium, and long alkyl chains in N-alkylnicotinamide were selected for phytotoxicity analyses, which were conducted on representative dicotyledonous (white mustard) and monocotyledonous (sorghum) plants. The study allowed the determination of the impact of compounds on the germination capacity as well as on the development of roots and stems of the tested plants. Interestingly, independently of the length of the alkyl chain or plant species, all QASs were established as non-phytotoxic. In addition, QSAR simulations, performed using the EPI Suite™ program pack, allowed the determination of the products’ potential toxicity toward fish, green algae, and daphnids along with the susceptibility to biodegradation. The obtained nicotinamide derivative with the shortest chain (butyl) can be considered practically non-toxic according to GHS criteria, whereas salts with medium (decyl) and longest (hexadecyl) substituent were included in the ‘acute II’ toxicity class. These findings were supported by the results of the toxicity tests performed on the model aquatic plant Lemna minor. It should be stressed that all synthesized salts exhibit not only a lack of potential for bioaccumulation but also lower toxicity than their fully synthetic analogs. Full article

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16 pages, 2879 KiB

Open AccessArticle

An Interplay between Mitochondrial and ER Targeting of a Bacterial Signal Peptide in Plants

by Tatiana Spatola Rossi and Verena Kriechbaumer

Plants 2023, 12(3), 617; https://doi.org/10.3390/plants12030617 - 31 Jan 2023

Viewed by 2616

Abstract

Protein targeting is essential in eukaryotic cells to maintain cell function and organelle identity. Signal peptides are a major type of targeting sequences containing a tripartite structure, which is conserved across all domains in life. They are frequently included in recombinant protein design [...] Read more.

Protein targeting is essential in eukaryotic cells to maintain cell function and organelle identity. Signal peptides are a major type of targeting sequences containing a tripartite structure, which is conserved across all domains in life. They are frequently included in recombinant protein design in plants to increase yields by directing them to the endoplasmic reticulum (ER) or apoplast. The processing of bacterial signal peptides by plant cells is not well understood but could aid in the design of efficient heterologous expression systems. Here we analysed the signal peptide of the enzyme PmoB from methanotrophic bacteria. In plant cells, the PmoB signal peptide targeted proteins to both mitochondria and the ER. This dual localisation was still observed in a mutated version of the signal peptide sequence with enhanced mitochondrial targeting efficiency. Mitochondrial targeting was shown to be dependent on a hydrophobic region involved in transport to the ER. We, therefore, suggest that the dual localisation could be due to an ER-SURF pathway recently characterised in yeast. This work thus sheds light on the processing of bacterial signal peptides by plant cells and proposes a novel pathway for mitochondrial targeting in plants. Full article

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16 pages, 1890 KiB

Open AccessArticle

Influence of Seed-Covering Layers on Caper Seed Germination

by María Laura Foschi, Mariano Juan, Bernardo Pascual and Nuria Pascual-Seva

Plants 2023, 12(3), 439; https://doi.org/10.3390/plants12030439 - 18 Jan 2023

Cited by 2 | Viewed by 2112

Abstract

Caper is a perennial shrub that is widespread in the Mediterranean Basin. Although the fruits contain many seeds, they germinate slowly and with very low percentages, due to their nondeep physiological dormancy. The influence of the testa and endosperm, as well as the [...] Read more.

Caper is a perennial shrub that is widespread in the Mediterranean Basin. Although the fruits contain many seeds, they germinate slowly and with very low percentages, due to their nondeep physiological dormancy. The influence of the testa and endosperm, as well as the effect of applying gibberellic acid (GA₃) solutions on seed germination to release its dormancy, are reported in this study. The mechanical resistance exerted by the testa and endosperm against radicle protrusion in mature caper seeds was measured. The best germination results were obtained with seeds devoid of testa wetted with water and with intact seeds wetted with a 500 mg L⁻¹ GA₃ solution, without statistical differences between them. The GA₃ addition triggers an increase in both the content of endogenous gibberellins (GA) and the GA/abscisic acid ratio, increasing germination. Its germination consists of two temporally separated events: testa cracking and endosperm piercing. Testa cracking begins in the hilum-micropillar area; it involves a signal from the embryo, which GA can replace, possibly by increasing the growth potential of the embryo. After testa cracking, the radicle emerges through a hole in the micropylar endosperm. The puncture force necessary to pierce the micropylar endosperm decreased drastically during the first day of imbibition, remaining practically constant until testa cracking, decreasing afterwards, regardless of the addition or not of gibberellins. Full article

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16 pages, 16847 KiB

Open AccessArticle

ATANN3 Is Involved in Extracellular ATP-Regulated Auxin Distribution in Arabidopsis thaliana Seedlings

by Jiawei Xu, Lijuan Han, Shuyan Xia, Ruojia Zhu, Erfang Kang and Zhonglin Shang

Plants 2023, 12(2), 330; https://doi.org/10.3390/plants12020330 - 10 Jan 2023

Cited by 6 | Viewed by 2149

Abstract

Extracellular ATP (eATP) plays multiple roles in plant growth and development, and stress responses. It has been revealed that eATP suppresses growth and alters the growth orientation of the root and hypocotyl of Arabidopsis thaliana by affecting auxin transport and localization in these [...] Read more.

Extracellular ATP (eATP) plays multiple roles in plant growth and development, and stress responses. It has been revealed that eATP suppresses growth and alters the growth orientation of the root and hypocotyl of Arabidopsis thaliana by affecting auxin transport and localization in these organs. However, the mechanism of the eATP-stimulated auxin distribution remains elusive. Annexins are involved in multiple aspects of plant cellular metabolism, while their role in response to apoplastic signals remains unclear. Here, by using the loss-of-function mutations, we investigated the role of AtANN3 in the eATP-regulated root and hypocotyl growth. Firstly, the inhibitory effects of eATP on root and hypocotyl elongation were weakened or impaired in the AtANN3 null mutants (atann3–1 and atann3–2). Meanwhile, the distribution of DR5-GUS and DR5-GFP indicated that the eATP-induced asymmetric distribution of auxin in the root tips or hypocotyl cells occurred in wild-type control plants, while in atann3–1 mutant seedlings, it was not observed. Further, the eATP-induced asymmetric distribution of PIN2-GFP in root-tip cells or that of PIN3-GFP in hypocotyl cells was reduced in atann3–1 seedlings. Finally, the eATP-induced asymmetric distribution of cytoplasmic vesicles in root-tip cells was impaired in atann3–1 seedlings. Based on these results, we suggest that AtANN3 may be involved in eATP-regulated seedling growth by regulating the distribution of auxin and auxin transporters in vegetative organs. Full article

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8 pages, 1068 KiB

Open AccessViewpoint

Cell Division and Meristem Dynamics in Fern Gametophytes

by Xiao Wu, Xing Liu, Shaoling Zhang and Yun Zhou

Plants 2023, 12(1), 209; https://doi.org/10.3390/plants12010209 - 3 Jan 2023

Cited by 2 | Viewed by 2606

Abstract

One of the most important questions in all multicellular organisms is how to define and maintain different cell fates during continuous cell division and proliferation. Plant meristems provide a unique research system to address this fundamental question because meristems dynamically maintain themselves and [...] Read more.

One of the most important questions in all multicellular organisms is how to define and maintain different cell fates during continuous cell division and proliferation. Plant meristems provide a unique research system to address this fundamental question because meristems dynamically maintain themselves and sustain organogenesis through balancing cell division and cell differentiation. Different from the gametophytes of seed plants that depend on their sporophytes and lack meristems, the gametophytes of seed-free ferns develop different types of meristems (including apical cell-based meristems and multicellular apical and marginal meristems) to promote independent growth and proliferation during the sexual gametophyte phase. Recent studies combining confocal time-lapse imaging and computational image analysis reveal the cellular basis of the initiation and proliferation of different types of meristems in fern gametophytes, providing new insights into the evolution of meristems in land plants. In this review, we summarize the recent progress in understanding the cell growth dynamics in fern gametophytes and discuss both conserved and diversified mechanisms underlying meristem cell proliferation in seed-free vascular plants. Full article

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20 pages, 4294 KiB

Open AccessArticle

Involvement of Target of Rapamycin (TOR) Signaling in the Regulation of Crosstalk between Ribosomal Protein Small Subunit 6 Kinase-1 (RPS6K-1) and Ribosomal Proteins

by Achala Bakshi, Mazahar Moin, Meher B. Gayatri, Aramati B. M. Reddy, Raju Datla, Maganti S. Madhav and Pulugurtha B. Kirti

Plants 2023, 12(1), 176; https://doi.org/10.3390/plants12010176 - 1 Jan 2023

Cited by 4 | Viewed by 3104

Abstract

The target of rapamycin (TOR) protein phosphorylates its downstream effector p70kDa ribosomal protein S6 kinases (S6K1) for ribosome biogenesis and translation initiation in eukaryotes. However, the molecular mechanism of TOR-S6K1-ribosomal protein (RP) signaling is not well understood in plants. In the present study, [...] Read more.

The target of rapamycin (TOR) protein phosphorylates its downstream effector p70kDa ribosomal protein S6 kinases (S6K1) for ribosome biogenesis and translation initiation in eukaryotes. However, the molecular mechanism of TOR-S6K1-ribosomal protein (RP) signaling is not well understood in plants. In the present study, we report the transcriptional upregulation of ribosomal protein large and small subunit (RPL and RPS) genes in the previously established TOR overexpressing transgenic lines of rice (in Oryza sativa ssp. indica, variety BPT-5204, TR-2.24 and TR-15.1) and of Arabidopsis thaliana (in Col 0 ecotype, ATR-1.4.27 and ATR-3.7.32). The mRNA levels of RP genes from this study were compared with those previously available in transcriptomic datasets on the expression of RPs in relation to TOR inhibitor and in the TOR-RNAi lines of Arabidopsis thaliana. We further analyzed TOR activity, i.e., S6K1 phosphorylation in SALK lines of Arabidopsis with mutation in rpl6, rpl18, rpl23, rpl24 and rps28C, where the rpl18 mutant showed inactivation of S6K1 phosphorylation. We also predicted similar putative Ser/Thr phosphorylation sites for ribosomal S6 kinases (RSKs) in the RPs of Oryza sativa ssp. indica and Arabidopsis thaliana. The findings of this study indicate that the TOR pathway is possibly interlinked in a cyclic manner via the phosphorylation of S6K1 as a modulatory step for the regulation of RP function to switch ‘on’/‘off’ the translational regulation for balanced plant growth. Full article

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15 pages, 1094 KiB

Open AccessEditor’s ChoiceReview

Wheat Crop under Waterlogging: Potential Soil and Plant Effects

by Isabel P. Pais, Rita Moreira, José N. Semedo, José C. Ramalho, Fernando C. Lidon, José Coutinho, Benvindo Maçãs and Paula Scotti-Campos

Plants 2023, 12(1), 149; https://doi.org/10.3390/plants12010149 - 28 Dec 2022

Cited by 27 | Viewed by 7750

Abstract

Inundation, excessive precipitation, or inadequate field drainage can cause waterlogging of cultivated land. It is anticipated that climate change will increase the frequency, intensity, and unpredictability of flooding events. This stress affects 10–15 million hectares of wheat every year, resulting in 20–50% yield [...] Read more.

Inundation, excessive precipitation, or inadequate field drainage can cause waterlogging of cultivated land. It is anticipated that climate change will increase the frequency, intensity, and unpredictability of flooding events. This stress affects 10–15 million hectares of wheat every year, resulting in 20–50% yield losses. Since this crop greatly sustains a population’s food demands, providing ca. 20% of the world’s energy and protein diets requirements, it is crucial to understand changes in soil and plant physiology under excess water conditions. Variations in redox potential, pH, nutrient availability, and electrical conductivity of waterlogged soil will be addressed, as well as their impacts in major plant responses, such as root system and plant development. Waterlogging effects at the leaf level will also be addressed, with a particular focus on gas exchanges, photosynthetic pigments, soluble sugars, membrane integrity, lipids, and oxidative stress. Full article

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25 pages, 480 KiB

Open AccessReview

Breeding for Higher Yields of Wheat and Rice through Modifying Nitrogen Metabolism

by Pornpipat Kasemsap and Arnold J. Bloom

Plants 2023, 12(1), 85; https://doi.org/10.3390/plants12010085 - 23 Dec 2022

Cited by 8 | Viewed by 3406

Abstract

Wheat and rice produce nutritious grains that provide 32% of the protein in the human diet globally. Here, we examine how genetic modifications to improve assimilation of the inorganic nitrogen forms ammonium and nitrate into protein influence grain yield of these crops. Successful [...] Read more.

Wheat and rice produce nutritious grains that provide 32% of the protein in the human diet globally. Here, we examine how genetic modifications to improve assimilation of the inorganic nitrogen forms ammonium and nitrate into protein influence grain yield of these crops. Successful breeding for modified nitrogen metabolism has focused on genes that coordinate nitrogen and carbon metabolism, including those that regulate tillering, heading date, and ammonium assimilation. Gaps in our current understanding include (1) species differences among candidate genes in nitrogen metabolism pathways, (2) the extent to which relative abundance of these nitrogen forms across natural soil environments shape crop responses, and (3) natural variation and genetic architecture of nitrogen-mediated yield improvement. Despite extensive research on the genetics of nitrogen metabolism since the rise of synthetic fertilizers, only a few projects targeting nitrogen pathways have resulted in development of cultivars with higher yields. To continue improving grain yield and quality, breeding strategies need to focus concurrently on both carbon and nitrogen assimilation and consider manipulating genes with smaller effects or that underlie regulatory networks as well as genes directly associated with nitrogen metabolism. Full article

21 pages, 3111 KiB

Open AccessEditor’s ChoiceArticle

Multiomic Approaches Reveal Hormonal Modulation and Nitrogen Uptake and Assimilation in the Initial Growth of Maize Inoculated with Herbaspirillum seropedicae

by Luiz Eduardo Souza da Silva Irineu, Cleiton de Paula Soares, Tatiane Sanches Soares, Felipe Astolpho de Almeida, Fabrício Almeida-Silva, Rajesh Kumar Gazara, Carlos Henrique Salvino Gadelha Meneses, Luciano Pasqualoto Canellas, Vanildo Silveira, Thiago Motta Venancio and Fabio Lopes Olivares

Plants 2023, 12(1), 48; https://doi.org/10.3390/plants12010048 - 22 Dec 2022

Cited by 9 | Viewed by 2713

Abstract

Herbaspirillum seropedicae is an endophytic bacterium that can fix nitrogen and synthesize phytohormones, which can lead to a plant growth-promoting effect when used as a microbial inoculant. Studies focused on mechanisms of action are crucial for a better understanding of the bacteria-plant interaction [...] Read more.

Herbaspirillum seropedicae is an endophytic bacterium that can fix nitrogen and synthesize phytohormones, which can lead to a plant growth-promoting effect when used as a microbial inoculant. Studies focused on mechanisms of action are crucial for a better understanding of the bacteria-plant interaction and optimization of plant growth-promoting response. This work aims to understand the underlined mechanisms responsible for the early stimulatory growth effects of H. seropedicae inoculation in maize. To perform these studies, we combined transcriptomic and proteomic approaches with physiological analysis. The results obtained eight days after inoculation (d.a.i) showed increased root biomass (233 and 253%) and shoot biomass (249 and 264%), respectively, for the fresh and dry mass of maize-inoculated seedlings and increased green content and development. Omics data analysis, before a positive biostimulation phenotype (5 d.a.i.) revealed that inoculation increases N-uptake and N-assimilation machinery through differentially expressed nitrate transporters and amino acid pathways, as well carbon/nitrogen metabolism integration by the tricarboxylic acid cycle and the polyamine pathway. Additionally, phytohormone levels of root and shoot tissues increased in bacterium-inoculated-maize plants, leading to feedback regulation by the ubiquitin-proteasome system. The early biostimulatory effect of H. seropedicae partially results from hormonal modulation coupled with efficient nutrient uptake-assimilation and a boost in primary anabolic metabolism of carbon–nitrogen integrative pathways. Full article

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15 pages, 1773 KiB

Open AccessArticle

Growth Parameters of Various Green Microalgae Species in Effluent from Biogas Reactors: The Importance of Effluent Concentration

by Elvira E. Ziganshina, Svetlana S. Bulynina, Ksenia A. Yureva and Ayrat M. Ziganshin

Plants 2022, 11(24), 3583; https://doi.org/10.3390/plants11243583 - 19 Dec 2022

Cited by 7 | Viewed by 2369

Abstract

The use of liquid waste as a feedstock for cultivation of microalgae can reduce water and nutrient costs and can also be used to treat wastewater with simultaneous production of biomass and valuable products. This study applied strategies to treat diluted anaerobic digester [...] Read more.

The use of liquid waste as a feedstock for cultivation of microalgae can reduce water and nutrient costs and can also be used to treat wastewater with simultaneous production of biomass and valuable products. This study applied strategies to treat diluted anaerobic digester effluent (ADE) as a residue of biogas reactors with moderate (87 ± 0.6 mg L⁻¹; 10% ADE) and elevated NH₄⁺-N levels (175 ± 1.1 mg L⁻¹; 20% ADE). The effect of ADE dilution on the acclimatization of various microalgae was studied based on the analysis of the growth and productivity of the tested green algae. Two species of the genus Chlorella showed robust growth in the 10–20% ADE (with a maximum total weight of 3.26 ± 0.18 g L⁻¹ for C. vulgaris and 2.81 ± 0.10 g L⁻¹ for C. sorokiniana). The use of 10% ADE made it possible to cultivate the strains of the family Scenedesmaceae more effectively than the use of 20% ADE. The growth of Neochloris sp. in ADE was the lowest compared to other microalgal strains. The results of this study demonstrated the feasibility of introducing individual green microalgae into the processes of nutrient recovery from ADE to obtain biomass with a high protein content. Full article

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13 pages, 11992 KiB

Open AccessArticle

Rubber Genotypes with Contrasting Drought Factor Index Revealed Different Mechanisms for Drought Resistance in Hevea brasiliensis

by Andi Nur Cahyo, Rudi Hari Murti, Eka Tarwaca Susila Putra, Fetrina Oktavia, Sigit Ismawanto and Pascal Montoro

Plants 2022, 11(24), 3563; https://doi.org/10.3390/plants11243563 - 16 Dec 2022

Cited by 3 | Viewed by 2181

Abstract

It is predicted that drought will be more frequent and sustained in the future, which may affect the decline of rubber tree production. Therefore, it is critical to research some of the variables related to the drought-resistance mechanism of the rubber tree. As [...] Read more.

It is predicted that drought will be more frequent and sustained in the future, which may affect the decline of rubber tree production. Therefore, it is critical to research some of the variables related to the drought-resistance mechanism of the rubber tree. As a result, it can be used to guide the selection of new rubber drought-resistance clones. The goal of this study was to identify drought-resistance mechanisms in rubber clones from the high drought factor index (DFI) group using ecophysiological and biochemical variables. The treatments consist of two factors, namely water deficit and contrasting clones based on the DFI variable. The first factor consisted of three levels, namely normal (fraction of transpirable soil water (FTSW) > 0.75), severe water deficit (0.1 < FTSW < 0.20), and recovery condition (FTSW > 0.75 after rewatering). The second factor consisted of seven clones, namely clones G239, GT1 (low DFI), G127, SP 217, PB 260 (moderate DFI), as well as G206 and RRIM 600 (high DFI). RRIM 600 had the highest DFI among the other clones as a drought-tolerance mechanism characteristic. Furthermore, clones RRIM 600, GT1, and G127 had lower stomatal conductance and transpiration rate than drought-sensitive clone PB 260. As a result, as drought avoidance mechanisms, clones RRIM 600, GT1, and G127 consume less water than clone PB 260. These findings indicated that clone RRIM 600 was a drought-resistant clone with drought tolerance and avoidance mechanisms. Full article

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26 pages, 2656 KiB

Open AccessEditor’s ChoiceReview

Plant Cell Wall Integrity Perturbations and Priming for Defense

by Sivakumar Swaminathan, Vincenzo Lionetti and Olga A. Zabotina

Plants 2022, 11(24), 3539; https://doi.org/10.3390/plants11243539 - 15 Dec 2022

Cited by 34 | Viewed by 6537

Abstract

A plant cell wall is a highly complex structure consisting of networks of polysaccharides, proteins, and polyphenols that dynamically change during growth and development in various tissues. The cell wall not only acts as a physical barrier but also dynamically responds to disturbances [...] Read more.

A plant cell wall is a highly complex structure consisting of networks of polysaccharides, proteins, and polyphenols that dynamically change during growth and development in various tissues. The cell wall not only acts as a physical barrier but also dynamically responds to disturbances caused by biotic and abiotic stresses. Plants have well-established surveillance mechanisms to detect any cell wall perturbations. Specific immune signaling pathways are triggered to contrast biotic or abiotic forces, including cascades dedicated to reinforcing the cell wall structure. This review summarizes the recent developments in molecular mechanisms underlying maintenance of cell wall integrity in plant–pathogen and parasitic interactions. Subjects such as the effect of altered expression of endogenous plant cell-wall-related genes or apoplastic expression of microbial cell-wall-modifying enzymes on cell wall integrity are covered. Targeted genetic modifications as a tool to study the potential of cell wall elicitors, priming of signaling pathways, and the outcome of disease resistance phenotypes are also discussed. The prime importance of understanding the intricate details and complete picture of plant immunity emerges, ultimately to engineer new strategies to improve crop productivity and sustainability. Full article

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14 pages, 2028 KiB

Open AccessArticle

TPC1-Type Channels in Physcomitrium patens: Interaction between EF-Hands and Ca²⁺

by Franko Mérida-Quesada, Fernando Vergara-Valladares, María Eugenia Rubio-Meléndez, Naomí Hernández-Rojas, Angélica González-González, Erwan Michard, Carlos Navarro-Retamal and Ingo Dreyer

Plants 2022, 11(24), 3527; https://doi.org/10.3390/plants11243527 - 15 Dec 2022

Cited by 1 | Viewed by 2102

Abstract

Two-pore channels (TPCs) are members of the superfamily of ligand-gated and voltage-sensitive ion channels in the membranes of intracellular organelles of eukaryotic cells. The evolution of ordinary plant TPC1 essentially followed a very conservative pattern, with no changes in the characteristic structural footprints [...] Read more.

Two-pore channels (TPCs) are members of the superfamily of ligand-gated and voltage-sensitive ion channels in the membranes of intracellular organelles of eukaryotic cells. The evolution of ordinary plant TPC1 essentially followed a very conservative pattern, with no changes in the characteristic structural footprints of these channels, such as the cytosolic and luminal regions involved in Ca²⁺ sensing. In contrast, the genomes of mosses and liverworts encode also TPC1-like channels with larger variations at these sites (TPC1b channels). In the genome of the model plant Physcomitrium patens we identified nine non-redundant sequences belonging to the TPC1 channel family, two ordinary TPC1-type, and seven TPC1b-type channels. The latter show variations in critical amino acids in their EF-hands essential for Ca²⁺ sensing. To investigate the impact of these differences between TPC1 and TPC1b channels, we generated structural models of the EF-hands of PpTPC1 and PpTPC1b channels. These models were used in molecular dynamics simulations to determine the frequency with which calcium ions were present in a coordination site and also to estimate the average distance of the ions from the center of this site. Our analyses indicate that the EF-hand domains of PpTPC1b-type channels have a lower capacity to coordinate calcium ions compared with those of common TPC1-like channels. Full article

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14 pages, 2794 KiB

Open AccessArticle

Exogenous Application of Glycine Betaine on Sweet Cherry Tree (Prunus avium L.): Effects on Tree Physiology and Leaf Properties

by Marta Serapicos, Sílvia Afonso, Berta Gonçalves and Ana Paula Silva

Plants 2022, 11(24), 3470; https://doi.org/10.3390/plants11243470 - 11 Dec 2022

Cited by 7 | Viewed by 2232

Abstract

Biostimulants, such as glycine betaine (GB), are a sustainable way to boost productivity and quality in fruit crops, even in adverse environment conditions. Sweet cherry (Prunus avium L.) is an important crop, which is very sensitive to abiotic stress. Known primarily for [...] Read more.

Biostimulants, such as glycine betaine (GB), are a sustainable way to boost productivity and quality in fruit crops, even in adverse environment conditions. Sweet cherry (Prunus avium L.) is an important crop, which is very sensitive to abiotic stress. Known primarily for its fruits, its leaves are also rich in bioactive substances, which, however, still have no commercial value. There are no studies about the effects of GB exogenous application on biochemical parameters of sweet cherry leaves and few studies about effects in sweet cherry tree physiology. This study was conducted in a Portuguese sweet cherry commercial orchard. Lapins sweet cherry trees were treated with a commercial product based on GB, at two different concentrations (0.25% and 0.40%). The applications were performed at three different phenological stages, according to the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale: 77, 81 and 86 BBCH. Both GB treatments improved leaf water status, photosynthetic pigments, soluble solids content, total phenolic contents, and antioxidant activity, resulting in better leaf water status regulation, greater photosynthetic capacity, and higher antioxidant activity. These results shows that GB can benefit sweet cherry tree physiology and provide new opportunities for sweet cherry leaves valorisation. Full article

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21 pages, 4022 KiB

Open AccessArticle

Water Stress Identification of Winter Wheat Crop with State-of-the-Art AI Techniques and High-Resolution Thermal-RGB Imagery

by Narendra S. Chandel, Yogesh A. Rajwade, Kumkum Dubey, Abhilash K. Chandel, A. Subeesh and Mukesh K. Tiwari

Plants 2022, 11(23), 3344; https://doi.org/10.3390/plants11233344 - 2 Dec 2022

Cited by 17 | Viewed by 4536

Abstract

Timely crop water stress detection can help precision irrigation management and minimize yield loss. A two-year study was conducted on non-invasive winter wheat water stress monitoring using state-of-the-art computer vision and thermal-RGB imagery inputs. Field treatment plots were irrigated using two irrigation systems [...] Read more.

Timely crop water stress detection can help precision irrigation management and minimize yield loss. A two-year study was conducted on non-invasive winter wheat water stress monitoring using state-of-the-art computer vision and thermal-RGB imagery inputs. Field treatment plots were irrigated using two irrigation systems (flood and sprinkler) at four rates (100, 75, 50, and 25% of crop evapotranspiration [ET_c]). A total of 3200 images under different treatments were captured at critical growth stages, that is, 20, 35, 70, 95, and 108 days after sowing using a custom-developed thermal-RGB imaging system. Crop and soil response measurements of canopy temperature (T_c), relative water content (RWC), soil moisture content (SMC), and relative humidity (RH) were significantly affected by the irrigation treatments showing the lowest T_c (22.5 ± 2 °C), and highest RWC (90%) and SMC (25.7 ± 2.2%) for 100% ET_c, and highest T_c (28 ± 3 °C), and lowest RWC (74%) and SMC (20.5 ± 3.1%) for 25% ET_c. The RGB and thermal imagery were then used as inputs to feature-extraction-based deep learning models (AlexNet, GoogLeNet, Inception V3, MobileNet V2, ResNet50) while, RWC, SMC, T_c, and RH were the inputs to function-approximation models (Artificial Neural Network (ANN), Kernel Nearest Neighbor (KNN), Logistic Regression (LR), Support Vector Machine (SVM) and Long Short-Term Memory (DL-LSTM)) to classify stressed/non-stressed crops. Among the feature extraction-based models, ResNet50 outperformed other models showing a discriminant accuracy of 96.9% with RGB and 98.4% with thermal imagery inputs. Overall, classification accuracy was higher for thermal imagery compared to RGB imagery inputs. The DL-LSTM had the highest discriminant accuracy of 96.7% and less error among the function approximation-based models for classifying stress/non-stress. The study suggests that computer vision coupled with thermal-RGB imagery can be instrumental in high-throughput mitigation and management of crop water stress. Full article

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25 pages, 1633 KiB

Open AccessArticle

Proteomic Analysis of Barley (Hordeum vulgare L.) Leaves in Response to Date Palm Waste Compost Application

by Emna Ghouili, Ghassen Abid, Moez Jebara, Rim Nefissi Ouertani, Ana Caroline de Oliveira, Mohamed El Ayed and Yordan Muhovski

Plants 2022, 11(23), 3287; https://doi.org/10.3390/plants11233287 - 29 Nov 2022

Cited by 2 | Viewed by 2298

Abstract

Composts are an emerging biofertilizers used in agronomy that can improve crop performance, but much less is known regarding their modes of action. The current study aimed to investigate the differentially abundant proteins (DAPs) in barley leaves associated with growth promotion induced by [...] Read more.

Composts are an emerging biofertilizers used in agronomy that can improve crop performance, but much less is known regarding their modes of action. The current study aimed to investigate the differentially abundant proteins (DAPs) in barley leaves associated with growth promotion induced by application of date palm waste compost. Morphophysiological measurements revealed that compost induced a significant increase in plant height, chlorophyll content, gas exchange parameters and plant biomass. LC-MS/MS analyses indicate that compost induced global changes in the proteome of barley leaves. A total of 62 DAPs (26 upregulated and 36 downregulated) among a total of 2233 proteins were identified in response to compost application. The expression of DAPs was further validated based on qRT-PCR. Compost application showed altered abundance of several proteins related to abiotic stress, plant defense, redox homeostasis, transport, tricarboxylic acid cycle, carbohydrate, amino acid, energy and protein metabolism. Furthermore, proteins related to metabolic processes of phytohormone, DNA methylation and secondary metabolites were induced. These results indicate that barley responds to compost application by complex metabolism pathways and may result in a positive alteration in a physiological and metabolic barley plant state which consequently could lead to improved growth and stress adaptation observed in compost-treated plants. Full article

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10 pages, 1004 KiB

Open AccessReview

ER Stress and the Unfolded Protein Response: Homeostatic Regulation Coordinate Plant Survival and Growth

by June-Sik Kim, Keiichi Mochida and Kazuo Shinozaki

Plants 2022, 11(23), 3197; https://doi.org/10.3390/plants11233197 - 22 Nov 2022

Cited by 7 | Viewed by 2621

Abstract

The endoplasmic reticulum (ER), a eukaryotic organelle, is the major site of protein biosynthesis. The disturbance of ER function by biotic or abiotic stress triggers the accumulation of misfolded or unfolded proteins in the ER. The unfolded protein response (UPR) is the best-studied [...] Read more.

The endoplasmic reticulum (ER), a eukaryotic organelle, is the major site of protein biosynthesis. The disturbance of ER function by biotic or abiotic stress triggers the accumulation of misfolded or unfolded proteins in the ER. The unfolded protein response (UPR) is the best-studied ER stress response. This transcriptional regulatory system senses ER stress, activates downstream genes that function to mitigate stress, and restores homeostasis. In addition to its conventional role in stress responses, recent reports indicate that the UPR is involved in plant growth and development. In this review, we summarize the current knowledge of ER stress sensing and the activation and downstream regulation of the UPR. We also describe how the UPR modulates both plant growth and stress tolerance by maintaining ER homeostasis. Lastly, we propose that the UPR is a major component of the machinery that balances the trade-off between plant growth and survival in a dynamic environment. Full article

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21 pages, 3403 KiB

Open AccessArticle

Exploiting Tomato Genotypes to Understand Heat Stress Tolerance

by Emma Fernández-Crespo, Luisa Liu-Xu, Carlos Albert-Sidro, Loredana Scalschi, Eugenio Llorens, Ana Isabel González-Hernández, Oscar Crespo, Carmen Gonzalez-Bosch, Gemma Camañes, Pilar García-Agustín and Begonya Vicedo

Plants 2022, 11(22), 3170; https://doi.org/10.3390/plants11223170 - 19 Nov 2022

Cited by 3 | Viewed by 2383

Abstract

Increased temperatures caused by climate change constitute a significant threat to agriculture and food security. The selection of improved crop varieties with greater tolerance to heat stress is crucial for the future of agriculture. To overcome this challenge, four traditional tomato varieties from [...] Read more.

Increased temperatures caused by climate change constitute a significant threat to agriculture and food security. The selection of improved crop varieties with greater tolerance to heat stress is crucial for the future of agriculture. To overcome this challenge, four traditional tomato varieties from the Mediterranean basin and two commercial genotypes were selected to characterize their responses at high temperatures. The screening of phenotypes under heat shock conditions allowed to classify the tomato genotypes as: heat-sensitive: TH-30, ADX2; intermediate: ISR-10 and Ailsa Craig; heat-tolerant: MM and MO-10. These results reveal the intra-genetical variation of heat stress responses, which can be exploited as promising sources of tolerance to climate change conditions. Two different thermotolerance strategies were observed. The MO-10 plants tolerance was based on the control of the leaf cooling mechanism and the rapid RBOHB activation and ABA signaling pathways. The variety MM displayed a different strategy based on the activation of HSP70 and 90, as well as accumulation of phenolic compounds correlated with early induction of PAL expression. The importance of secondary metabolism in the recovery phase has been also revealed. Understanding the molecular events allowing plants to overcome heat stress constitutes a promising approach for selecting climate resilient tomato varieties. Full article

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16 pages, 1761 KiB

Open AccessArticle

The Influence of Fertilization and Plant Density on the Dry Matter Yield and Quality of Black Mustard [Brassica nigra (L.) Koch]: An Alternative Forage Crop

by Stella Karydogianni, Ioannis Roussis, Antonios Mavroeidis, Ioanna Kakabouki, Evangelia Tigka, Dimitrios Beslemes, Panteleimon Stavropoulos, Nikolaos Katsenios, Eleni Tsiplakou and Dimitrios Bilalis

Plants 2022, 11(20), 2683; https://doi.org/10.3390/plants11202683 - 12 Oct 2022

Cited by 6 | Viewed by 2504

Abstract

Black mustard [Brassica nigra (L.) Koch] is mainly cultivated as a seed crop, and there is a lack of information on biomass quality and its potential for animal feeding. A 2-year field experiment was set up in a split-plot design with 2 [...] Read more.

Black mustard [Brassica nigra (L.) Koch] is mainly cultivated as a seed crop, and there is a lack of information on biomass quality and its potential for animal feeding. A 2-year field experiment was set up in a split-plot design with 2 main plots (plant densities: 46 and 76 plants m⁻²), 4 sub-plots (fertilization levels: control, compost, urea with and without urease and nitrification inhibitors) and 3 replications for each treatment. The highest dry matter yield (17.55–18.34 tn ha⁻¹) was observed in high-density plots fertilized with urea fertilizer coated with double (nitrification and urease) inhibitors. In terms of the qualitive parameters of total above-ground biomass, the highest crude protein (CP) content was achieved in plots with low density and urea with double inhibitors. Moreover, the highest neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of above-ground biomass were found under compost and urea with double inhibitors. The high ADF, NDF and relatively high CP content characterized that black mustard aerial biomass can meet the requirements of lactating animals, and therefore the production of black mustard biomass as a forage crop could be of great importance. As a conclusion, black mustard cultivated at plant densities higher than 46 plants m⁻² and under inorganic fertilization, especially with urea coated with double inhibitors, could be successfully used as a novel forage crop in ruminants’ diets. Full article

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17 pages, 2264 KiB

Open AccessArticle

Light-Dependence of Formate (C₁) and Acetate (C₂) Transport and Oxidation in Poplar Trees

by Kolby J. Jardine, Joseph Lei, Suman Som, Daisy Souza, Chaevien S. Clendinen, Hardeep Mehta, Pubudu Handakumbura, Markus Bill and Robert P. Young

Plants 2022, 11(16), 2080; https://doi.org/10.3390/plants11162080 - 9 Aug 2022

Cited by 1 | Viewed by 2475

Abstract

Although apparent light inhibition of leaf day respiration is a widespread reported phenomenon, the mechanisms involved, including utilization of alternate respiratory pathways and substrates and light inhibition of TCA cycle enzymes are under active investigation. Recently, acetate fermentation was highlighted as a key [...] Read more.

Although apparent light inhibition of leaf day respiration is a widespread reported phenomenon, the mechanisms involved, including utilization of alternate respiratory pathways and substrates and light inhibition of TCA cycle enzymes are under active investigation. Recently, acetate fermentation was highlighted as a key drought survival strategy mediated through protein acetylation and jasmonate signaling. Here, we evaluate the light-dependence of acetate transport and assimilation in Populus trichocarpa trees using the dynamic xylem solution injection (DXSI) method developed here for continuous studies of C1 and C2 organic acid transport and light-dependent metabolism. Over 7 days, 1.0 L of [¹³C]formate and [¹³C₂]acetate solutions were delivered to the stem base of 2-year old potted poplar trees, while continuous diurnal observations were made in the canopy of CO₂, H₂O, and isoprene gas exchange together with δ¹³CO₂. Stem base injection of 10 mM [¹³C₂]acetate induced an overall pattern of canopy branch headspace ¹³CO₂ enrichment (δ¹³CO₂ +27‰) with a diurnal structure in δ¹³CO₂ reaching a mid-day minimum followed by a maximum shortly after darkening where δ¹³CO₂ values rapidly increased up to +12‰. In contrast, 50 mM injections of [¹³C]formate were required to reach similar δ¹³CO₂ enrichment levels in the canopy with δ¹³CO₂ following diurnal patterns of transpiration. Illuminated leaves of detached poplar branches pretreated with 10 mM [¹³C₂]acetate showed lower δ¹³CO₂ (+20‰) compared to leaves treated with 10 mM [¹³C]formate (+320‰), the opposite pattern observed at the whole plant scale. Following dark/light cycles at the leaf-scale, rapid, strong, and reversible enhancements in headspace δ¹³CO₂ by up to +60‰ were observed in [¹³C₂]acetate-treated leaves which showed enhanced dihydrojasmonic acid and TCA cycle intermediate concentrations. The results are consistent with acetate in the transpiration stream as an effective activator of the jasmonate signaling pathway and respiratory substrate. The shorter lifetime of formate relative to acetate in the transpiration stream suggests rapid formate oxidation to CO₂ during transport to the canopy. In contrast, acetate is efficiently transported to the canopy where an increased allocation towards mitochondrial dark respiration occurs at night. The results highlight the potential for an effective integration of acetate into glyoxylate and TCA cycles and the light-inhibition of citrate synthase as a potential regulatory mechanism controlling the diurnal allocation of acetate between anabolic and catabolic processes. Full article

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2021

Jump to: 2024, 2023, 2022, 2020, 2019

11 pages, 2883 KiB

Open AccessArticle

Involvement of Auxin Biosynthesis and Transport in the Antheridium and Prothalli Formation in Lygodium japonicum

by Natsumi Ohishi, Nanami Hoshika, Mizuho Takeda, Kyomi Shibata, Hisakazu Yamane, Takao Yokota and Masashi Asahina

Plants 2021, 10(12), 2709; https://doi.org/10.3390/plants10122709 - 9 Dec 2021

Cited by 5 | Viewed by 2999

Abstract

The spores of Lygodium japonicum, cultured in the dark, form a filamentous structure called protonema. Earlier studies have shown that gibberellin (GA) induces protonema elongation, along with antheridium formation, on the protonema. In this study, we have performed detailed morphological analyses to [...] Read more.

The spores of Lygodium japonicum, cultured in the dark, form a filamentous structure called protonema. Earlier studies have shown that gibberellin (GA) induces protonema elongation, along with antheridium formation, on the protonema. In this study, we have performed detailed morphological analyses to investigate the roles of multiple phytohormones in antheridium formation, protonema elongation, and prothallus formation in L. japonicum. GA₄ methyl ester is a potent GA that stimulates both protonema elongation and antheridium formation. We found that these effects were inhibited by simultaneous application of abscisic acid (ABA). On the other hand, IAA (indole-3-acetic acid) promoted protonema elongation but reduced antheridium formation, while these effects were partially recovered by transferring to an IAA-free medium. An auxin biosynthesis inhibitor, PPBo (4-phenoxyphenylboronic acid), and a transport inhibitor, TIBA (2,3,5-triiodobenzoic acid), both inhibited protonema elongation and antheridium formation. L. japonicum prothalli are induced from germinating spores under continuous white light. Such development was negatively affected by PPBo, which induced smaller-sized prothalli, and TIBA, which induced aberrantly shaped prothalli. The evidence suggests that the crosstalk between these plant hormones might regulate protonema elongation and antheridium formation in L. japonicum. Furthermore, the possible involvement of auxin in the prothalli development of L. japonicum is suggested. Full article

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15 pages, 4322 KiB

Open AccessArticle

Mercury-Induced Phytotoxicity and Responses in Upland Cotton (Gossypium hirsutum L.) Seedlings

by Lei Mei, Yueyi Zhu, Xianwen Zhang, Xiujuan Zhou, Zhentao Zhong, Huazu Li, Yingjun Li, Xiaohu Li, Muhammad Khan Daud, Jinhong Chen and Shuijin Zhu

Plants 2021, 10(8), 1494; https://doi.org/10.3390/plants10081494 - 21 Jul 2021

Cited by 18 | Viewed by 2716

Abstract

Cotton is a potential and excellent candidate to balance both agricultural production and remediation of mercury-contained soil, as its main production fiber hardly involves into food chains. However, in cotton, there is known rarely about the tolerance and response to mercury (Hg [...] Read more.

Cotton is a potential and excellent candidate to balance both agricultural production and remediation of mercury-contained soil, as its main production fiber hardly involves into food chains. However, in cotton, there is known rarely about the tolerance and response to mercury (Hg) environments. In this study, the biochemical and physiological damages, in response to Hg concentrations (0, 1, 10, 50 and 100 µM), were investigated in upland cotton seedlings. The results on germination of cottonseeds indicated the germination rates were suppressed by high Hg levels, as the decrease of percentage was more than 10% at 1000 µM Hg. Shoots and roots’ growth were significantly inhibited over 10 µM Hg. The inhibitor rates (IR) in fresh weight were close in values between shoots and roots, whereas those in dry weight the root growth were more obviously influenced by Hg. In comparison of organs, the growth inhibition ranked as root > leaf > stem. The declining of translocation factor (TF) opposed the Hg level as even low to 0.05 at 50 µM Hg. The assimilation in terms of photosynthesis, of cotton plants, was affected negatively by Hg, as evidenced from the performances on pigments (chlorophyll a and b) and gas exchange (Intercellular CO₂ concentration (Ci), CO₂ assimilation rate (Pn) and stomatal conductance (Gs)). Sick phenotypes on leaf surface included small white zone, shrinking and necrosis. Membrane lipid peroxidation and leakage were Hg dose-dependent as indicated by malondialdehyde (MDA) content and relative conductivity (RC) values in leaves and roots. More than 10 µM Hg damaged antioxidant enzyme system in both leaves and roots (p < 0.05). Concludingly, 10 µM Hg post negative consequences to upland cotton plants in growth, physiology and biochemistry, whereas high phytotoxicity and damage appeared at more than 50 µM Hg concentration. Full article

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14 pages, 1512 KiB

Open AccessArticle

Application of Trehalose and Salicylic Acid Mitigates Drought Stress in Sweet Basil and Improves Plant Growth

by Faisal Zulfiqar, Jianjun Chen, Patrick M. Finnegan, Adnan Younis, Muhammad Nafees, Walid Zorrig and Karim Ben Hamed

Plants 2021, 10(6), 1078; https://doi.org/10.3390/plants10061078 - 27 May 2021

Cited by 63 | Viewed by 5471

Abstract

Trehalose (Tre) and salicylic acid (SA) are increasingly used to mitigate drought stress in crop plants. In this study, a pot experiment was performed to study the influence of Tre and SA applied individually or in combination on the growth, photosynthesis, and antioxidant [...] Read more.

Trehalose (Tre) and salicylic acid (SA) are increasingly used to mitigate drought stress in crop plants. In this study, a pot experiment was performed to study the influence of Tre and SA applied individually or in combination on the growth, photosynthesis, and antioxidant responses of sweet basil (Ocimum basilicum L.) exposed to drought stress. Basil plants were watered to 60% or 100% field capacity with or without treatment with 30 mM Tre and/or 1 mM SA. Drought negatively affected growth, physiological parameters, and antioxidant responses. Application of Tre and/or SA resulted in growth recovery, increased photosynthesis, and reduced oxidative stress. Application of Tre mitigated the detrimental effects of drought more than SA. Furthermore, co-application of Tre and SA largely eliminated the negative impact of drought by reducing oxidative stress through increased activities of antioxidant enzymes superoxide dismutase, peroxidase, and catalase, as well as the accumulation of the protective osmolytes proline and glycine betaine. Combined Tre and SA application improved water use efficiency and reduced the amount of malondialdehyde in drought-stressed plants. Our results suggested that combined application of Tre and SA may trigger defense mechanisms of sweet basil to better mitigate oxidative stress induced by drought stress, thereby improving plant growth. Full article

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20 pages, 4056 KiB

Open AccessArticle

Antagonistic Interaction between Phosphinothricin and Nepeta rtanjensis Essential Oil Affected Ammonium Metabolism and Antioxidant Defense of Arabidopsis Grown In Vitro

by Slavica Dmitrović, Milan Dragićević, Jelena Savić, Milica Milutinović, Suzana Živković, Vuk Maksimović, Dragana Matekalo, Mirjana Perišić and Danijela Mišić

Plants 2021, 10(1), 142; https://doi.org/10.3390/plants10010142 - 12 Jan 2021

Cited by 1 | Viewed by 2599

Abstract

Phosphinothricin (PPT) is one of the most widely used herbicides. PTT targets glutamine synthetase (GS) activity in plants, and its phytotoxicity is ascribed to ammonium accumulation and reactive oxygen species bursts, which drives rapid lipid peroxidation of cell membranes. In agricultural fields, PPT [...] Read more.

Phosphinothricin (PPT) is one of the most widely used herbicides. PTT targets glutamine synthetase (GS) activity in plants, and its phytotoxicity is ascribed to ammonium accumulation and reactive oxygen species bursts, which drives rapid lipid peroxidation of cell membranes. In agricultural fields, PPT is extensively sprayed on plant foliage; however, a portion of the herbicide reaches the soil. According to the present study, PPT absorbed via roots can be phytotoxic to Arabidopsis, inducing more adverse effects in roots than in shoots. Alterations in plant physiology caused by 10 days exposure to herbicide via roots are reflected through growth suppression, reduced chlorophyll content, perturbations in the sugar and organic acid metabolism, modifications in the activities and abundances of GS, catalase, peroxidase, and superoxide dismutase. Antagonistic interaction of Nepeta rtanjensis essential oil (NrEO) and PPT, emphasizes the existence of complex control mechanisms at the transcriptional and posttranslational level, which result in the mitigation of PPT-induced ammonium toxicity and in providing more efficient antioxidant defense of plants. Simultaneous application of the two agents in the field cannot be recommended; however, NrEO might be considered as the PPT post-treatment for reducing harmful effects of herbicide residues in the soil on non-target plants. Full article

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2020

Jump to: 2024, 2023, 2022, 2021, 2019

13 pages, 1040 KiB

Open AccessArticle

Aerobic Barley Mg-protoporphyrin IX Monomethyl Ester Cyclase is Powered by Electrons from Ferredoxin

by David Stuart, Malin Sandström, Helmy M. Youssef, Shakhira Zakhrabekova, Poul Erik Jensen, David W. Bollivar and Mats Hansson

Plants 2020, 9(9), 1157; https://doi.org/10.3390/plants9091157 - 8 Sep 2020

Cited by 12 | Viewed by 3885

Abstract

Chlorophyll is the light-harvesting molecule central to the process of photosynthesis. Chlorophyll is synthesized through 15 enzymatic steps. Most of the reactions have been characterized using recombinant proteins. One exception is the formation of the isocyclic E-ring characteristic of chlorophylls. This reaction is [...] Read more.

Chlorophyll is the light-harvesting molecule central to the process of photosynthesis. Chlorophyll is synthesized through 15 enzymatic steps. Most of the reactions have been characterized using recombinant proteins. One exception is the formation of the isocyclic E-ring characteristic of chlorophylls. This reaction is catalyzed by the Mg-protoporphyrin IX monomethyl ester cyclase encoded by Xantha-l in barley (Hordeum vulgare L.). The Xantha-l gene product (XanL) is a membrane-bound diiron monooxygenase, which requires additional soluble and membrane-bound components for its activity. XanL has so far been impossible to produce as an active recombinant protein for in vitro assays, which is required for deeper biochemical and structural analyses. In the present work, we performed cyclase assays with soluble and membrane-bound fractions of barley etioplasts. Addition of antibodies raised against ferredoxin or ferredoxin-NADPH oxidoreductase (FNR) inhibited assays, strongly suggesting that reducing electrons for the cyclase reaction involves ferredoxin and FNR. We further developed a completely recombinant cyclase assay. Expression of active XanL required co-expression with an additional protein, Ycf54. In vitro cyclase activity was obtained with recombinant XanL in combination with ferredoxin and FNR. Our experiment demonstrates that the cyclase is a ferredoxin-dependent enzyme. Ferredoxin is part of the photosynthetic electron-transport chain, which suggests that the cyclase reaction might be connected to photosynthesis under light conditions. Full article

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14 pages, 988 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Hydrogenases and the Role of Molecular Hydrogen in Plants

by Grace Russell, Faisal Zulfiqar and John T. Hancock

Plants 2020, 9(9), 1136; https://doi.org/10.3390/plants9091136 - 2 Sep 2020

Cited by 24 | Viewed by 5780

Abstract

Molecular hydrogen (H₂) has been suggested to be a beneficial treatment for a range of species, from humans to plants. Hydrogenases catalyze the reversible oxidation of H₂, and are found in many organisms, including plants. One of the cellular [...] Read more.

Molecular hydrogen (H₂) has been suggested to be a beneficial treatment for a range of species, from humans to plants. Hydrogenases catalyze the reversible oxidation of H₂, and are found in many organisms, including plants. One of the cellular effects of H₂ is the selective removal of reactive oxygen species (ROS) and reactive nitrogen species (RNS), specifically hydroxyl radicals and peroxynitrite. Therefore, the function of hydrogenases and the action of H₂ needs to be reviewed in the context of the signalling roles of a range of redox active compounds. Enzymes can be controlled by the covalent modification of thiol groups, and although motifs targeted by nitric oxide (NO) can be predicted in hydrogenases sequences it is likely that the metal prosthetic groups are the target of inhibition. Here, a selection of hydrogenases, and the possibility of their control by molecules involved in redox signalling are investigated using a bioinformatics approach. Methods of treating plants with H₂ along with the role of H₂ in plants is also briefly reviewed. It is clear that studies report significant effects of H₂ on plants, improving growth and stress responses, and therefore future work needs to focus on the molecular mechanisms involved. Full article

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17 pages, 3143 KiB

Open AccessArticle

The Recovery of Soybean Plants after Short-Term Cadmium Stress

by Renata Holubek, Joanna Deckert, Inga Zinicovscaia, Nikita Yushin, Konstantin Vergel, Marina Frontasyeva, Alexander V. Sirotkin, Donald Samdumu Bajia and Jagna Chmielowska-Bąk

Plants 2020, 9(6), 782; https://doi.org/10.3390/plants9060782 - 22 Jun 2020

Cited by 17 | Viewed by 4255

Abstract

Background: Cadmium is a non-essential heavy metal, which is toxic even in relatively low concentrations. Although the mechanisms of Cd toxicity are well documented, there is limited information concerning the recovery of plants after exposure to this metal. Methods: The present study describes [...] Read more.

Background: Cadmium is a non-essential heavy metal, which is toxic even in relatively low concentrations. Although the mechanisms of Cd toxicity are well documented, there is limited information concerning the recovery of plants after exposure to this metal. Methods: The present study describes the recovery of soybean plants treated for 48 h with Cd at two concentrations: 10 and 25 mg/L. In the frame of the study the growth, cell viability, level of membrane damage makers, mineral content, photosynthesis parameters, and global methylation level have been assessed directly after Cd treatment and/or after 7 days of growth in optimal conditions. Results: The results show that exposure to Cd leads to the development of toxicity symptoms such as growth inhibition, increased cell mortality, and membrane damage. After a recovery period of 7 days, the exposed plants showed no differences in relation to the control in all analyzed parameters, with an exception of a slight reduction in root length and changed content of potassium, magnesium, and manganese. Conclusions: The results indicate that soybean plants are able to efficiently recover even after relatively severe Cd stress. On the other hand, previous exposure to Cd stress modulated their mineral uptake. Full article

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13 pages, 1019 KiB

Open AccessArticle

Evaluation of Nitrogen Nutrition in Diminishing Water Deficiency at Different Growth Stages of Maize by Chlorophyll Fluorescence Parameters

by Attila Simkó, Gáspár Soma Gáspár, László Kiss, Péter Makleit and Szilvia Veres

Plants 2020, 9(6), 676; https://doi.org/10.3390/plants9060676 - 27 May 2020

Cited by 6 | Viewed by 2490

Abstract

Efficient nitrogen (N) nutrition has been reported to have the potential to alleviate the drought stress damages by maintaining metabolic activities even at low tissue water potential. The goal of our research was to find a correlation on the genotype level between the [...] Read more.

Efficient nitrogen (N) nutrition has been reported to have the potential to alleviate the drought stress damages by maintaining metabolic activities even at low tissue water potential. The goal of our research was to find a correlation on the genotype level between the effect of different amounts of nitrogen nutrition and water supply at different growth stages. A small-plot experiment was established with three maize hybrids and three levels of nitrogen, and two different amounts of water supply were applied during the vegetation period of 2018 and 2019. Chlorophyll fluorescence parameters were detected, as well as potential and actual photochemical efficiency of PSII, at three growth stages: eight-leaf stage, tasseling, silking. At physiological maturity, the yield of hybrids was also measured. While only genotype differences were described among the investigated parameters in the V8 stage, treatment effects were also realized based on the measured chlorophyll fluorescence parameters during the tasseling and silking stages. Beyond the significant effect of irrigation, a similar impact was declared in the case of 80 kg ha⁻¹ N treatment at the later growth stages. Pronounced correlation was described between chlorophyll fluorescence parameters and yield mainly under irrigated conditions. Our result suggested that lower N nutrition may be sufficient mainly under irrigated conditions, and in vivo chlorophyll fluorescence parameters are appropriate for detecting the effect of environmental factors in different growth stages. Full article

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16 pages, 17577 KiB

Open AccessFeature PaperArticle

A Phosphite Dehydrogenase Variant with Promiscuous Access to Nicotinamide Cofactor Pools Sustains Fast Phosphite-Dependent Growth of Transplastomic Chlamydomonas reinhardtii

by Edoardo Cutolo, Matteo Tosoni, Simone Barera, Luis Herrera-Estrella, Luca Dall’Osto and Roberto Bassi

Plants 2020, 9(4), 473; https://doi.org/10.3390/plants9040473 - 8 Apr 2020

Cited by 13 | Viewed by 5233

Abstract

Heterologous expression of the NAD⁺-dependent phosphite dehydrogenase (PTXD) bacterial enzyme from Pseudomonas stutzerii enables selective growth of transgenic organisms by using phosphite as sole phosphorous source. Combining phosphite fertilization with nuclear expression of the ptxD transgene was shown to be an [...] Read more.

Heterologous expression of the NAD⁺-dependent phosphite dehydrogenase (PTXD) bacterial enzyme from Pseudomonas stutzerii enables selective growth of transgenic organisms by using phosphite as sole phosphorous source. Combining phosphite fertilization with nuclear expression of the ptxD transgene was shown to be an alternative to herbicides in controlling weeds and contamination of algal cultures. Chloroplast expression of ptxD in Chlamydomonas reinhardtii was proposed as an environmentally friendly alternative to antibiotic resistance genes for plastid transformation. However, PTXD activity in the chloroplast is low, possibly due to the low NAD⁺/NADP⁺ ratio, limiting the efficiency of phosphite assimilation. We addressed the intrinsic constraints of the PTXD activity in the chloroplast and improved its catalytic efficiency in vivo via rational mutagenesis of key residues involved in cofactor binding. Transplastomic lines carrying a mutagenized PTXD version promiscuously used NADP⁺ and NAD⁺ for converting phosphite into phosphate and grew faster compared to those expressing the wild type protein. The modified PTXD enzyme also enabled faster and reproducible selection of transplastomic colonies by directly plating on phosphite-containing medium. These results allow using phosphite as selective agent for chloroplast transformation and for controlling biological contaminants when expressing heterologous proteins in algal chloroplasts, without compromising on culture performance. Full article

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15 pages, 2011 KiB

Open AccessArticle

Foliar Application of Calcium and Growth Regulators Modulate Sweet Cherry (Prunus avium L.) Tree Performance

by Sofia Correia, Filipa Queirós, Helena Ferreira, Maria Cristina Morais, Sílvia Afonso, Ana Paula Silva and Berta Gonçalves

Plants 2020, 9(4), 410; https://doi.org/10.3390/plants9040410 - 26 Mar 2020

Cited by 36 | Viewed by 5970

Abstract

Cracking of sweet cherry (Prunus avium L.) fruits is caused by rain events close to harvest. This problem has occurred in most cherry growing regions with significant economic losses. Several orchard management practices have been applied to reduce the severity of this [...] Read more.

Cracking of sweet cherry (Prunus avium L.) fruits is caused by rain events close to harvest. This problem has occurred in most cherry growing regions with significant economic losses. Several orchard management practices have been applied to reduce the severity of this disorder, like the foliar application of minerals or growth regulators. In the present study, we hypothesized that preharvest spray treatments improve the physiological performance of sweet cherry trees and could also mitigate environmental stressful conditions. Effects of repeated foliar spraying of calcium (Ca), gibberellic acid (GA₃), abscisic acid (ABA), salicylic acid (SA), glycine betaine (GB), and the biostimulant Ascophyllum nodosum (AN) on the physiological and biochemical performance of ‘Skeena’ sweet cherry trees during two consecutive years (without Ca in 2015 and in 2016 with addition of Ca) were studied. Results showed that in general spray treatments improved the physiological performance and water status of the trees. AN and ABA sprays were demonstrated to be the best compounds for increasing yield and reducing cherry cracking as well as improving photosynthetic performance and leaf metabolites content. In conclusion, AN and ABA might be promising tools in the fruit production system. Full article

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15 pages, 4997 KiB

Open AccessArticle

Nitro-Oleic Acid in Seeds and Differently Developed Seedlings of Brassica napus L.

by Martin Vollár, Gábor Feigl, Dóra Oláh, Attila Horváth, Árpád Molnár, Norbert Kúsz, Attila Ördög, Dezső Csupor and Zsuzsanna Kolbert

Plants 2020, 9(3), 406; https://doi.org/10.3390/plants9030406 - 24 Mar 2020

Cited by 13 | Viewed by 3972

Abstract

Similar to animals, it has recently been proven that nitro-fatty acids such as nitro-linolenic acid and nitro-oleic acid (NO₂-OA) have relevant physiological roles as signalling molecules also in plants. Although NO₂-OA is of great therapeutic importance, its presence in [...] Read more.

Similar to animals, it has recently been proven that nitro-fatty acids such as nitro-linolenic acid and nitro-oleic acid (NO₂-OA) have relevant physiological roles as signalling molecules also in plants. Although NO₂-OA is of great therapeutic importance, its presence in plants as a free fatty acid has not been observed so far. Since Brassica napus (oilseed rape) is a crop with high oleic acid content, the abundance of NO₂-OA in its tissues can be assumed. Therefore, we quantified NO₂-OA in B. napus seeds and differently developed seedlings. In all samples, NO₂-OA was detectable at nanomolar concentrations. The seeds showed the highest NO₂-OA content, which decreased during germination. In contrast, nitric oxide (•NO) levels increased in the early stages of germination and seedling growth. Exogenous NO₂-OA treatment (100 µM, 24 h) of Brassica seeds resulted in significantly increased •NO level and induced germination capacity compared to untreated seeds. The results of in vitro approaches (4-Amino-5-methylamino-2′,7′-difluorofluorescein (DAF-FM) fluorescence, •NO-sensitive electrode) supported the •NO liberating capacity of NO₂-OA. We observed for the first time that Brassica seeds and seedlings contain free NO₂-OA which may be involved in germination as an •NO donor as suggested both by the results of exogenous NO₂-OA treatment of seeds and in vitro approaches. Due to their high NO₂-OA content, Brassica sprouts can be considered as a good source of dietary NO₂-OA intake. Full article

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21 pages, 27639 KiB

Open AccessArticle

Effects of Light and Daytime on the Regulation of Chitosan-Induced Stomatal Responses and Defence in Tomato Plants

by Zalán Czékus, Péter Poór, Irma Tari and Attila Ördög

Plants 2020, 9(1), 59; https://doi.org/10.3390/plants9010059 - 2 Jan 2020

Cited by 15 | Viewed by 4735

Abstract

Closure of stomata upon pathogenesis is among the earliest plant immune responses. However, our knowledge is very limited about the dependency of plant defence responses to chitosan (CHT) on external factors (e.g., time of the day, presence, or absence of light) in intact [...] Read more.

Closure of stomata upon pathogenesis is among the earliest plant immune responses. However, our knowledge is very limited about the dependency of plant defence responses to chitosan (CHT) on external factors (e.g., time of the day, presence, or absence of light) in intact plants. CHT induced stomatal closure before dark/light transition in leaves treated at 17:00 hrs and stomata were closed at 09:00 hrs in plants treated at dawn and in the morning. CHT was able to induce generation of reactive oxygen species (ROS) in guard cells in the first part of the light phase, but significant nitric oxide production was observable only at 15:00 hrs. The actual quantum yield of PSII electron transport (Φ_PSII) decreased upon CHT treatments at 09:00 hrs in guard cells but it declined only at dawn in mesophyll cells after the treatment at 17:00 hrs. Expression of Pathogenesis-related 1 (PR1) and Ethylene Response Factor 1 were already increased at dawn in the CHT-treated leaves but PR1 expression was inhibited in the dark. CHT-induced systemic response was also observed in the distal leaves of CHT-treated ones. Our results suggest a delayed and daytime-dependent defence response of tomato plants after CHT treatment at night and under darkness. Full article

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2019

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29 pages, 3171 KiB

Open AccessFeature PaperReview

Genetic Engineering for Global Food Security: Photosynthesis and Biofortification

by Andrew John Simkin

Plants 2019, 8(12), 586; https://doi.org/10.3390/plants8120586 - 9 Dec 2019

Cited by 36 | Viewed by 9523

Abstract

Increasing demands for food and resources are challenging existing markets, driving a need to continually investigate and establish crop varieties with improved yields and health benefits. By the later part of the century, current estimates indicate that a >50% increase in the yield [...] Read more.

Increasing demands for food and resources are challenging existing markets, driving a need to continually investigate and establish crop varieties with improved yields and health benefits. By the later part of the century, current estimates indicate that a >50% increase in the yield of most of the important food crops including wheat, rice and barley will be needed to maintain food supplies and improve nutritional quality to tackle what has become known as ‘hidden hunger’. Improving the nutritional quality of crops has become a target for providing the micronutrients required in remote communities where dietary variation is often limited. A number of methods to achieve this have been investigated over recent years, from improving photosynthesis through genetic engineering, to breeding new higher yielding varieties. Recent research has shown that growing plants under elevated [CO₂] can lead to an increase in Vitamin C due to changes in gene expression, demonstrating one potential route for plant biofortification. In this review, we discuss the current research being undertaken to improve photosynthesis and biofortify key crops to secure future food supplies and the potential links between improved photosynthesis and nutritional quality. Full article

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