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11 pages, 814 KiB

Open AccessArticle

When Light Is Crucial, but Wind Is Rather Trivial: A Basil Case Study

by Efterpi Florou, Angela Politi, Evangelia Andreadaki, Konstantinos Vrakas, Hariklia Spaliara, Alexandros Neli, Christina Eleni Koulopoulou, Athanasios Koulopoulos, Filippos Bantis and George Zervoudakis

Plants 2024, 13(22), 3221; https://doi.org/10.3390/plants13223221 - 16 Nov 2024

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Abstract

Light intensity and wind are critical environmental factors of abiotic stress on plants, triggering a considerable number of morphological and physiological responses. This study tested the hypothesis that different light and wind conditions (full sunlight ± wind, shade ± wind) would affect the [...] Read more.

Light intensity and wind are critical environmental factors of abiotic stress on plants, triggering a considerable number of morphological and physiological responses. This study tested the hypothesis that different light and wind conditions (full sunlight ± wind, shade ± wind) would affect the leaf content of photosynthetic pigments and anthocyanins, as well as the plant height, the fresh and dry weight of the aboveground part, and Water-Use Efficiency on Ocimum basilicum plants. About 16 days after the application of the different conditions, all leaf pigments of the shaded plants exhibited increased contents compared to the lightened ones. Subsequently, this response was enhanced until the 39th day, which was the final day of the experiment. Furthermore, shaded plants grew taller, although their fresh and dry weight and Water-Use Efficiency were lower than that of the corresponding lightened ones. On the other hand, wind did not have any effect on pigment content. Concerning the plant growth indexes, reduced values were observed on the wind-treated plants. The above results demonstrate a considerable effect of light intensity while the applied wind seems to be mild enough to induce important plant responses, partially confirming the hypothesis studied. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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29 pages, 3671 KiB

Open AccessArticle

Screening for Drought Tolerance Within a Common Bean (Phaseolus vulgaris L.) Landrace Accessions Core Collection from the Lazio Region of Italy

by Enrica Alicandri, Ester Badiani, Anna Rita Paolacci, Emilio Lo Presti, Roberta Caridi, Roberto Rea, Francesco Pati, Maurizio Badiani, Mario Ciaffi and Agostino Sorgonà

Plants 2024, 13(22), 3132; https://doi.org/10.3390/plants13223132 - 7 Nov 2024

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Abstract

In the present work, a subset extracted from a core collection of common beans (Phaseolus vulgaris L.) landrace accessions from the Lazio region in central Italy was used to identify the most suitable drought-tolerant or -susceptible genotypes. By applying several morpho-physiological and [...] Read more.

In the present work, a subset extracted from a core collection of common beans (Phaseolus vulgaris L.) landrace accessions from the Lazio region in central Italy was used to identify the most suitable drought-tolerant or -susceptible genotypes. By applying several morpho-physiological and agronomic selection criteria recommended by the available literature, we conducted a pre-screening experiment under controlled conditions on a primary group of 24 landraces. These landraces were chosen to represent the diversity in the Lazio region in terms of geographical provenance, elevation, landform, growth habit, customary water management in the field, and native gene pool. Pre-screening under controlled conditions allowed us to identify two subsets of landraces: one exhibiting the most drought-tolerance and one showing the most susceptibility to drought. These two subsets were then tested in field trials using two water treatments, i.e., normal irrigation versus no irrigation. Such field experiments were simultaneously conducted at two sites within the Lazio region, deliberately chosen to maximize their differences in terms of pedo-climatic conditions. This notwithstanding, the core findings from the two separate field experiments were remarkably consistent and coherent among each other, highlighting a notable degree of variability within the group of the tested landraces. In general, the morpho-physiological traits considered were found to be less responsive to water shortage than yield parameters. A statistically significant Landrace × Treatment interaction was found for almost all the yield parameters considered, suggesting that certain genotypes are more susceptible than others to water shortage. By taking into account the concept of “yield stability”, i.e., the ability to maintain comparatively high yields even under conditions of water scarcity, certain common bean landraces were found to be the most promising, in terms of drought tolerance. Two genotype pairs, in particular, could be of interest for studying the morpho-physiological and molecular mechanisms underlying drought tolerance in common bean, as well as for identifying quantitative trait loci associated with water scarcity, which could be beneficially employed in breeding programs. The results reported here also suggest that pre-screening under laboratory conditions, followed by targeted field trials, can constitute a reliable, efficient, and resourceful combined approach, in which morpho-physiological traits measured on juvenile plants might play a role in predicting drought tolerance at the agronomic level. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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18 pages, 3578 KiB

Open AccessArticle

Acidic Stress Induces Cytosolic Free Calcium Oscillation, and an Appropriate Low pH Helps Maintain the Circadian Clock in Arabidopsis

by Wei Chen, Jing Xu, Jia Chen, Jun-Feng Wang, Shu Zhang and Zhen-Ming Pei

Plants 2024, 13(21), 3107; https://doi.org/10.3390/plants13213107 - 4 Nov 2024

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Abstract

Acidic stress is a formidable environmental factor that exerts adverse effects on plant growth and development, ultimately leading to a potential reduction in agricultural productivity. A low pH triggers Ca²⁺ influx across the plasma membrane (PM), eliciting distinct responses under various acidic [...] Read more.

Acidic stress is a formidable environmental factor that exerts adverse effects on plant growth and development, ultimately leading to a potential reduction in agricultural productivity. A low pH triggers Ca²⁺ influx across the plasma membrane (PM), eliciting distinct responses under various acidic pH levels. However, the underlying mechanisms by which Arabidopsis plant cells generate stimulus-specific Ca²⁺ signals in response to acidic stress remain largely unexplored. The experimentally induced stimulus may elicit spikes in cytosolic free Ca²⁺ concentration ([Ca²⁺]_i) spikes or complex [Ca²⁺]_i oscillations that persist for 20 min over a long-term of 24 h or even several days within the plant cytosol and chloroplast. This study investigated the increase in [Ca²⁺]_i under a gradient of low pH stress ranging from pH 3.0 to 6.0. Notably, the peak of [Ca²⁺]_i elevation was lower at pH 4.0 than at pH 3.0 during the initial 8 h, while other pH levels did not significantly increase [Ca²⁺]_i compared to low acidic stress conditions. Lanthanum chloride (LaCl₃) can effectively suppress the influx of [Ca²⁺]_i from the apoplastic to the cytoplasm in plants under acid stress, with no discernible difference in intracellular calcium levels observed in Arabidopsis. Following 8 h of acid treatment in the darkness, the intracellular baseline Ca²⁺ levels in Arabidopsis were significantly elevated when exposed to low pH stress. A moderately low pH, specifically 4.0, may function as a spatial-temporal input into the circadian clock system. These findings suggest that acid stimulation can exert a continuous influence on intracellular calcium levels, as well as plant growth and development. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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14 pages, 10118 KiB

Open AccessArticle

RrWRKY1, a Transcription Factor, Is Involved in the Regulation of the Salt Stress Response in Rosa rugosa

by Fengqi Zang, Qichao Wu, Zhe Li, Ling Li, Xiaoman Xie, Boqiang Tong, Shuhan Yu, Zhaoan Liang, Chunxue Chu, Dekui Zang and Yan Ma

Plants 2024, 13(21), 2973; https://doi.org/10.3390/plants13212973 - 24 Oct 2024

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Abstract

Salt stress has become a major environmental problem affecting plant growth and development. Some WRKY transcription factors have been reported to be involved in the salt stress response in plants. However, there are few studies on the involvement of WRKYs in the salt [...] Read more.

Salt stress has become a major environmental problem affecting plant growth and development. Some WRKY transcription factors have been reported to be involved in the salt stress response in plants. However, there are few studies on the involvement of WRKYs in the salt stress response in Rosa rugosa. In this study, we isolated a salt tolerance gene, RrWRKY1, from R. rugosa. RrWRKY1 was found to belong to Group I of the WRKY family, and it was specifically expressed in leaves and petals. RrWRKY1 expression was upregulated under NaCl stress in rose leaves. After silencing RrWRKY1 in R. rugosa, transgenic plants showed dry leaves and black and brown veins, indicating sensitivity to salt stress. At the same time, the transcription levels of the salt tolerance-related genes RrNHX1, RrABF2, RrRD22, RrNCED1, and RrHKT1 also changed significantly. The superoxide dismutase (SOD) and peroxidase (POD) activities decreased, the proline content decreased, and the malondialdehyde (MDA) content in the gene-silenced plants increased, indicating that RrWRKY1 regulates the salt tolerance of R. rugosa. In addition, the overexpression of RrWRKY1 in Arabidopsis thaliana improved the germination rate and the average of the main root and lateral root lengths, and the transgenic plants had a larger number of lateral roots than the WT plants under salt stress. This study provides candidate gene resources for salinity tolerance breeding and a theoretical basis for analyzing the salinity tolerance mechanism of the WRKY gene. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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14 pages, 4102 KiB

Open AccessArticle

The Role of PLATZ6 in Raffinose Family Oligosaccharides Loading of Leaves via PLATZ Family Characterization in Cucumber

by Peiqi Wang, Haofeng Teng, Dan Qiao, Fei Liang, Kaikai Zhu, Minmin Miao and Bing Hua

Plants 2024, 13(19), 2825; https://doi.org/10.3390/plants13192825 - 9 Oct 2024

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Abstract

The plant AT protein and zinc-binding protein (PLATZ) genes, a novel cluster of plant-specific zinc-finger-dependent DNA-binding proteins, play a crucial role in regulating stress response and plant development. However, there has been little study focus on the role of the cucumber [...] Read more.

The plant AT protein and zinc-binding protein (PLATZ) genes, a novel cluster of plant-specific zinc-finger-dependent DNA-binding proteins, play a crucial role in regulating stress response and plant development. However, there has been little study focus on the role of the cucumber PLATZ family in assimilating loading in leaves. (1) In this study, a total of 12 PLATZ genes were identified from the cucumber genome. The cucumber PLATZ genes were clustered into five groups, and unevenly distributed on five chromosomes. A single pair of cucumber PLATZ genes underwent segmental duplication. (2) The results of genome-wide expression analysis suggested that the cucumber PLATZ genes were widely expressed in a wide range of cucumber tissues, with three PLATZ (PLATZ2, PLATZ6, and PLATZ12) genes exhibiting high expression in the vascular tissues of cucumber leaves. PLATZ2, PLATZ6, and PLATZ12 proteins were primarily located in cytomembrane and nucleus. (3) In VIGS-PLATZ6 plants, the expression of Galactinol synthase 1 (GolS1) and STACHYOSE SYNTHASE (STS), two genes involved in the synthesis of raffinose family oligosaccharides (RFOs) were observed to be decreased in cucumber leaves. In conclusion, the comprehensive analysis of the cucumber PLATZ family and the preliminary functional verification of PLATZ6 lay the foundation for the molecular and physiological functions of cucumber PLATZ genes. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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16 pages, 3701 KiB

Open AccessArticle

Gene Expression Divergence in Eugenia uniflora Highlights Adaptation across Contrasting Atlantic Forest Ecosystems

by Andreia C. Turchetto-Zolet, Fabiano Salgueiro, Frank Guzman, Nicole M. Vetö, Nureyev F. Rodrigues, Natalia Balbinott, Marcia Margis-Pinheiro and Rogerio Margis

Plants 2024, 13(19), 2719; https://doi.org/10.3390/plants13192719 - 28 Sep 2024

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Abstract

Understanding the evolution and the effect of plasticity in plant responses to environmental changes is crucial to combat global climate change. It is particularly interesting in species that survive in distinct environments, such as Eugenia uniflora, which thrives in contrasting ecosystems within the [...] Read more.

Understanding the evolution and the effect of plasticity in plant responses to environmental changes is crucial to combat global climate change. It is particularly interesting in species that survive in distinct environments, such as Eugenia uniflora, which thrives in contrasting ecosystems within the Atlantic Forest (AF). In this study, we combined transcriptome analyses of plants growing in nature (Restinga and Riparian Forest) with greenhouse experiments to unveil the DEGs within and among adaptively divergent populations of E. uniflora. We compared global gene expression among plants from two distinct ecological niches. We found many differentially expressed genes between the two populations in natural and greenhouse-cultivated environments. The changes in how genes are expressed may be related to the species’ ability to adapt to specific environmental conditions. The main difference in gene expression was observed when plants from Restinga were compared with their offspring cultivated in greenhouses, suggesting that there are distinct selection pressures underlying the local environmental and ecological factors of each Restinga and Riparian Forest ecosystem. Many of these genes engage in the stress response, such as water and nutrient transport, temperature, light intensity, and gene regulation. The stress-responsive genes we found are potential genes for selection in these populations. These findings revealed the adaptive potential of E. uniflora and contributed to our understanding of the role of gene expression reprogramming in plant evolution and niche adaptation. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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16 pages, 9124 KiB

Open AccessArticle

Photosynthetic Performance of Oil Palm Genotypes under Drought Stress

by Carmenza Montoya, Edison Daza, Fernan Santiago Mejía-Alvarado, Arley Fernando Caicedo-Zambrano, Iván Ayala-Díaz, Rodrigo Ruiz-Romero and Hernán Mauricio Romero

Plants 2024, 13(19), 2705; https://doi.org/10.3390/plants13192705 - 27 Sep 2024

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Abstract

Water deficiency and potential drought periods could be important ecological factors influencing cultivation areas and productivity once different crops are established. The principal supply of vegetable oil for oil crops is oil palm, and new challenges are emerging in the face of climatic [...] Read more.

Water deficiency and potential drought periods could be important ecological factors influencing cultivation areas and productivity once different crops are established. The principal supply of vegetable oil for oil crops is oil palm, and new challenges are emerging in the face of climatic changes. This study investigated the photosynthetic performance of 12 genotypes of Elaeis exposed to drought stress under controlled conditions. The assay included genotypes of Elaeis guineensis, Elaeis oleifera, and the interspecific O×G hybrid (E. oleifera × E. guineensis). The principal results showed that the E. guineensis genotype was the most efficient at achieving photosynthesis under drought stress conditions, followed by the hybrid and E. oleifera genotypes. The physiological parameters showed good prospects for vegetal breeding with different O×G hybrids, mainly because of their ability to maintain the equilibrium between CO₂ assimilation and stomatal aperture. We validated 11 genes associated with drought tolerance, but no differences were detected. These results indicate that no allelic variants were represented in the RNA during sampling for the validated genotypes. In conclusion, this study helps to define genotypes that can be used as parental lines for oil palm improvement. The gas exchange data showed that drought stress tolerance could define guidelines to incorporate the available genetic resources in breeding programs across the early selection in nursery stages. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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20 pages, 5610 KiB

Open AccessArticle

Biochemical and Proteomic Analyses in Drought-Tolerant Wheat Mutants Obtained by Gamma Irradiation

by Ayşe Şen, Tamer Gümüş, Aslıhan Temel, İrfan Öztürk and Özge Çelik

Plants 2024, 13(19), 2702; https://doi.org/10.3390/plants13192702 - 27 Sep 2024

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Abstract

The bread wheat cultivar (Triticum aestivum L. cv. Sagittario) as a parental line and its mutant, drought-tolerant lines (Mutant lines 4 and 5) were subjected to polyethylene glycol (PEG)-induced drought. Drought stress resulted in decreased chlorophyll levels and the accumulation of proline [...] Read more.

The bread wheat cultivar (Triticum aestivum L. cv. Sagittario) as a parental line and its mutant, drought-tolerant lines (Mutant lines 4 and 5) were subjected to polyethylene glycol (PEG)-induced drought. Drought stress resulted in decreased chlorophyll levels and the accumulation of proline and TBARS, despite increases in activities of catalase, peroxidase, and superoxide dismutase enzymes. Transcription of the genes encoding these enzymes and delta-1-pyrroline 5-carboxylase synthetase was induced by drought. 2-DE gel electrophoresis analysis identified differentially expressed proteins (DEPs) in the mutant lines, which are distinguished by “chloroplast”, “mitochondrion”, “pyruvate dehydrogenase complex”, and “homeostatic process” terms. The drought tolerance of the mutant lines might be attributed to improved photosynthesis, efficient ATP synthesis, and modified antioxidant capacity. In addition to proteomics data, the drought tolerance of wheat genotypes might also be assessed by chlorophyll content and TaPOX gene expression. To our knowledge, this is the first proteomic analysis of gamma-induced mutants of bread wheat. These findings are expected to be utilized in plant breeding studies. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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22 pages, 11500 KiB

Open AccessArticle

Overexpression of Auxin/Indole-3-Acetic Acid Gene TrIAA27 Enhances Biomass, Drought, and Salt Tolerance in Arabidopsis thaliana

by Muhammad Zafar Iqbal, Yuzhou Liang, Muhammad Anwar, Akash Fatima, Muhammad Jawad Hassan, Asif Ali, Qilin Tang and Yan Peng

Plants 2024, 13(19), 2684; https://doi.org/10.3390/plants13192684 - 25 Sep 2024

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Abstract

White clover (Trifolium repens L.) is an important forage and aesthetic plant species, but it is susceptible to drought and heat stress. The phytohormone auxin regulates several aspects of plant development and alleviates the effects of drought stress in plants, including white [...] Read more.

White clover (Trifolium repens L.) is an important forage and aesthetic plant species, but it is susceptible to drought and heat stress. The phytohormone auxin regulates several aspects of plant development and alleviates the effects of drought stress in plants, including white clover, by involving auxin/indole acetic acid (Aux/IAA) family genes. However, Aux/IAA genes and the underlying mechanism of auxin-mediated drought response remain elusive in white clover. To extend our understanding of the multiple functions of Aux/IAAs, the current study described the characterization of a member of the Aux/IAA family TrIAA27 of white clover. TrIAA27 protein had conserved the Aux/IAA family domain and shared high sequence similarity with the IAA27 gene of a closely related species and Arabidopsis. Expression of TrIAA27 was upregulated in response to heavy metal, drought, salt, NO, Ca²⁺, H₂O₂, Spm, ABA, and IAA treatments, while downregulated under cold stress in the roots and leaves of white clover. TrIAA27 protein was localized in the nucleus. Constitutive overexpression of TrIAA27 in Arabidopsis thaliana led to enhanced hypocotyl length, root length, plant height, leaf length and width, and fresh and dry weights under optimal and stress conditions. There was Improved photosynthesis activity, chlorophyll content, survival rate, relative water content, endogenous catalase (CAT), and peroxidase (POD) concentration with a significantly lower electrolyte leakage percentage, malondialdehyde (MDA) content, and hydrogen peroxide (H₂O₂) concentration in overexpression lines compared to wild-type Arabidopsis under drought and salt stress conditions. Exposure to stress conditions resulted in relatively weaker roots and above-ground plant growth inhibition, enhanced endogenous levels of major antioxidant enzymes, which correlated well with lower lipid peroxidation, lower levels of reactive oxygen species, and reduced cell death in overexpression lines. The data of the current study demonstrated that TrIAA27 is involved in positively regulating plant growth and development and could be considered a potential target gene for further use, including the breeding of white clover for higher biomass with improved root architecture and tolerance to abiotic stress. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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22 pages, 12133 KiB

Open AccessArticle

Abiotic Stress Effect on Agastache mexicana subsp. mexicana Yield: Cultivated in Two Contrasting Environments with Organic Nutrition and Artificial Shading

by Judith Morales-Barrera, Juan Reséndiz-Muñoz, Blas Cruz-Lagunas, José Luis Fernández-Muñoz, Flaviano Godínez-Jaimes, Tania de Jesús Adame-Zambrano, Mirna Vázquez-Villamar, Teollincacihuatl Romero-Rosales, María Teresa Zagaceta-Álvarez, Karen Alicia Aguilar-Cruz, Jorge Estrada-Martínez and Miguel Angel Gruintal-Santos

Plants 2024, 13(18), 2661; https://doi.org/10.3390/plants13182661 - 23 Sep 2024

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Abstract

Research on medicinal plants is essential for their conservation, propagation, resistance to environmental stress, and domestication. The use of organic nutrition has been demonstrated to improve soil fertility and plant quality. It is also important to study the effects of the Basic Cation [...] Read more.

Research on medicinal plants is essential for their conservation, propagation, resistance to environmental stress, and domestication. The use of organic nutrition has been demonstrated to improve soil fertility and plant quality. It is also important to study the effects of the Basic Cation Saturation Ratio (BCSR) approach, which is a topic where there is currently controversy and limited scientific information. Evaluating the growth and yields of Agastache mexicana subsp. mexicana (Amm) in different environments is crucial for developing effective propagation and domestication strategies. This includes examining warm and subhumid environments with rain in summer in comparison to mild environments with summer rain. Significant differences were observed in the effects of cold, waterlogging, and heat stresses on the plant’s biomass yield and the morphometric-quantitative modeling by means of isolines. The biomass yield was 56% higher in environment one compared to environment two, 19% higher in environment one with organic nutrition, and 48% higher in environment two with organic nutrition compared to using only BCSR nutrition. In the second harvesting cycle, the plants in environment one did not survive, while the plants in environment two managed to survive without needing additional nutrition. Statistical and mathematical analyses provided information about the population or sample. Additionally, further analysis using isolines as a new approach revealed new insights into understanding phenology and growth issues. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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12 pages, 5370 KiB

Open AccessArticle

Hydrogen Peroxide Is Involved in Methane-Alleviated Cadmium Toxicity in Alfalfa (Medicago sativa L.) Seedlings by Enhancing Cadmium Chelation onto Root Cell Walls

by Yingying Zhao, Jie Yang, Feiyan Jiang and Gan Zhao

Plants 2024, 13(18), 2639; https://doi.org/10.3390/plants13182639 - 21 Sep 2024

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Abstract

Although previous studies have demonstrated that methane (CH₄) can mitigate the toxicity of cadmium (Cd) in alfalfa seedlings, the CH₄-rich water used in these studies may create hypoxic conditions, potentially influencing the experimental outcomes. Therefore, this study aimed to [...] Read more.

Although previous studies have demonstrated that methane (CH₄) can mitigate the toxicity of cadmium (Cd) in alfalfa seedlings, the CH₄-rich water used in these studies may create hypoxic conditions, potentially influencing the experimental outcomes. Therefore, this study aimed to investigate whether CH₄ can reduce Cd toxicity in alfalfa seedlings without the interference of hypoxia and to analyze its underlying mechanisms. Here, it was observed that supplementing oxygen with saturated CH₄-rich water can significantly alleviate the inhibition of 75 μM CdCl₂ on the growth of alfalfa (Medicago sativa L.) seedlings. Less Cd accumulation was also observed in both root and shoot parts, which could be explained by the CH₄-altered cell wall components in alfalfa seedling roots, including covalent and ionic soluble pectin, and the degree of demethylation in pectin, thus enabling a higher proportion of Cd binding to the cell walls and reducing the entry of Cd into the cells. The above actions of CH₄ were accompanied by an increase in hydrogen peroxide (H₂O₂) content and NADPH oxidase activity, which could be blocked by the addition of the NADPH oxidase inhibitor diphenylene iodonium (DPI). Taken together, these results implied that exogenously applied CH₄ could alleviate Cd toxicity in alfalfa seedlings by enhancing Cd chelation onto the root cell walls, which might be closely associated with NADPH oxidase-dependent H₂O₂ signals. These findings could provide insight into the mechanism through which CH₄ alleviates Cd toxicity in alfalfa plants. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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23 pages, 6957 KiB

Open AccessArticle

Exploring Thinopyrum spp. Group 7 Chromosome Introgressions to Improve Durum Wheat Performance under Intense Daytime and Night-Time Heat Stress at Anthesis

by Gloria Giovenali, Maria Lia Di Romana, Alessandra Capoccioni, Vinicio Riccardi, Ljiljana Kuzmanović and Carla Ceoloni

Plants 2024, 13(18), 2605; https://doi.org/10.3390/plants13182605 - 18 Sep 2024

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Abstract

Durum wheat (DW) is one of the major crops grown in the Mediterranean area, a climate-vulnerable region where the increase in day/night (d/n) temperature is severely threatening DW yield stability. In order to improve DW heat tolerance, the introgression of chromosomal segments derived [...] Read more.

Durum wheat (DW) is one of the major crops grown in the Mediterranean area, a climate-vulnerable region where the increase in day/night (d/n) temperature is severely threatening DW yield stability. In order to improve DW heat tolerance, the introgression of chromosomal segments derived from the wild gene pool is a promising strategy. Here, four DW-Thinopyrum spp. near-isogenic recombinant lines (NIRLs) were assessed for their physiological response and productive performance after intense heat stress (IH, 37/27 °C d/n) had been applied for 3 days at anthesis. The NIRLs included two primary types (R5, R112), carriers (+) of a differently sized Th. ponticum 7el1L segment on the DW 7AL arm, and two corresponding secondary types (R69-9/R5, R69-9/R112), possessing a Th. elongatum 7EL segment distally inserted into the 7el1L ones. Their response to the IH stress was compared to that of corresponding non-carrier sib lines (−) and the heat-tolerant cv. Margherita. Overall, the R112+, R69-9/R5+ and R69-9/R112+ NIRLs exhibited a tolerant behaviour towards the applied stress, standing out for the maintenance of leaf relative water content but also for the accumulation of proline and soluble sugars in the flag leaf and the preservation of photosynthetic efficiency. As a result, all the above three NIRLs (R112+ > R69-9/R5+ > R69-9/R112+) displayed good yield stability under the IH, also in comparison with cv. Margherita. R112+ particularly relied on the strength of spike fertility/grain number traits, while R69-9/R5+ benefited from efficient compensation by the grain weight increase. This work largely confirmed and further substantiated the value of exploiting the wild germplasm of Thinopyrum species as a useful source for the improvement of DW tolerance to even extreme abiotic stress conditions, such as the severe heat treatment throughout day- and night-time applied here. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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24 pages, 13550 KiB

Open AccessArticle

Physiological and Transcriptomic Analyses Demonstrate the Ca²⁺-Mediated Alleviation of Salt Stress in Magnolia wufengensis

by Xiuting Zhao, Zhonglong Zhu, Ziyang Sang, Luyi Ma, Qun Yin and Zhongkui Jia

Plants 2024, 13(17), 2418; https://doi.org/10.3390/plants13172418 - 29 Aug 2024

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Abstract

Magnolia wufengensis, a newly discovered ornamental species in the Magnoliaceae family, is susceptible to salinity. Moreover, Ca²⁺ is an essential element for plant growth and is receiving increasing attention for its ability to mitigate the negative effects of environmental stress on [...] Read more.

Magnolia wufengensis, a newly discovered ornamental species in the Magnoliaceae family, is susceptible to salinity. Moreover, Ca²⁺ is an essential element for plant growth and is receiving increasing attention for its ability to mitigate the negative effects of environmental stress on plants. In the present study, we investigated the effect of Ca²⁺ on the growth and transcriptome of M. wufengensis under salt stress. The treatments used here were as follows: control, NaCl (150 mmol/L), CaCl₂ (5 mmol/L), and NaCl (150 mmol/L) + CaCl₂ (5 mmol/L). After a 60-day treatment period, plant growth indices were determined, and leaves were collected for physiological analysis and transcriptome investigation. The combined application of NaCl and CaCl₂ alleviated phenotypic damage and restored seedling growth. Moreover, RNA sequencing data revealed that in the Na vs. control group and the NaCa vs. Na group, there were 968 and 2632 differentially expressed genes, respectively, which were both primarily enriched in secondary metabolism, glutathione metabolism, signaling hormone metabolism, glucose metabolism, and amino acid metabolism. These pathways were analyzed to screen key genes: the adenosine triphosphate (ATP)-binding cassette efflux transporter G1 (ABCG1) genes, which are related to transmembrane transport; the calmodulin genes, which are related to signal transmission; and the glutathione S-transferase (GST), glutathione peroxidase (GPX), and peroxidase (POD) genes related to antioxidant enzymes. Lastly, we constructed a hypothesis model of Ca²⁺-enhanced salt tolerance in M. wufengensis. This study reveals the potential mechanisms by which Ca²⁺ enhances the salt tolerance of M. wufengensis and provides a theoretical reference for its cultivation in saline areas. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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16 pages, 5009 KiB

Open AccessArticle

LrHSP17.2 Plays an Important Role in Abiotic Stress Responses by Regulating ROS Scavenging and Stress-Related Genes in Lilium regale

by Shaokang Tang, Qin Ling, Qiqi Ma, Yuqing Cheng, Peng Mei, Yuan Miao, Yuanzhi Pan, Yin Jia, Mengxi Wu, Xue Yong and Beibei Jiang

Plants 2024, 13(17), 2416; https://doi.org/10.3390/plants13172416 - 29 Aug 2024

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Abstract

As an important part of heat shock response module, heat shock proteins (HSP) play an important role in plant defense response against heat stress; however, the involvement of the majority of the HSP family members against other abiotic stresses remains poorly understood. In [...] Read more.

As an important part of heat shock response module, heat shock proteins (HSP) play an important role in plant defense response against heat stress; however, the involvement of the majority of the HSP family members against other abiotic stresses remains poorly understood. In the present study, LrHSP17.2 was identified and its function against abiotic stress was analyzed. The expression level of LrHSP17.2 was significantly induced by heat. Heterologous transgenes of LrHSP17.2 showed that LrHSP17.2 can increase the activity of catalase, peroxidase, superoxide dismutase to removes excess reactive oxygen species (ROS), maintain the stability of the membrane structure, and regulate genes related to antioxidant enzymes and defense under abiotic stress. In addition, LrHSP17.2 could be regulated by exogenous abscisic acid and melatonin, and the related hormone synthesis genes of transgenic plants were significantly up-regulated under heat stress. Taken together, our results revealed that LrHSP17.2 is involved in regulating abiotic stress responses by regulating ROS scavenging and stress-related genes in Lilium regale. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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22 pages, 3501 KiB

Open AccessArticle

Leaf Membrane Stability under High Temperatures as an Indicator of Heat Tolerance in Potatoes and Genome-Wide Association Studies to Understand the Underlying Genetics

by Amaka M. Ifeduba, Shuyang Zhen, Jeewan Pandey and M. Isabel Vales

Plants 2024, 13(16), 2175; https://doi.org/10.3390/plants13162175 - 6 Aug 2024

Cited by 1 | Viewed by 1441

Abstract

High temperatures during the crop growing season are becoming more frequent and unpredictable, resulting in reduced crop productivity and quality. Heat stress disrupts plant metabolic processes that affect cell membrane composition and integrity. Cell membrane permeability, ion leakage, and heat shock proteins have [...] Read more.

High temperatures during the crop growing season are becoming more frequent and unpredictable, resulting in reduced crop productivity and quality. Heat stress disrupts plant metabolic processes that affect cell membrane composition and integrity. Cell membrane permeability, ion leakage, and heat shock proteins have been evaluated to screen for heat tolerance in plants. In potatoes, it is unclear whether leaf membrane stability under heat stress is correlated with underground tuber productivity and quality. The main goal of this study was to evaluate if leaf membrane relative electrolyte conductivity (REC) under high temperatures could be used to identify heat-tolerant potato genotypes. Electrolyte leakage assays, correlation estimations, and genome-wide association studies were carried out in 215 genotypes. Expression levels of small heat shock protein 18 (sHSP18) were evaluated in the heat-sensitive potato variety Russet Burbank and compared with those of the heat-tolerant variety Vanguard Russet using Western blotting. Significant differences were observed among genotypes for leaf membrane REC under extreme heat (50°C); REC values ranged from 47.0–99.5%. Leaf membrane REC was positively correlated with tuber external and internal defects and negatively correlated with yield. REC was negatively correlated with the content of several tuber minerals, such as nitrogen, magnesium, and manganese. Eleven quantitative trait loci (QTLs) were identified for leaf membrane REC, explaining up to 13.8% of the phenotypic variance. Gene annotation in QTL areas indicated associations with genes controlling membrane solute transport and plant responses to abiotic stresses. Vanguard Russet had lower leaf REC and higher expression of sHSP18 under high-temperature stress. Our findings indicate that leaf membrane REC under high temperatures can be used as an indicator of potato heat tolerance. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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29 pages, 20329 KiB

Open AccessArticle

Comparative Effects of Water Scarcity on the Growth and Development of Two Common Bean (Phaseolus vulgaris L.) Genotypes with Different Geographic Origin (Mesoamerica/Andean)

by Paula-Maria Galan, Lacramioara-Carmen Ivanescu, Livia-Ioana Leti, Maria Magdalena Zamfirache and Dragoș-Lucian Gorgan

Plants 2024, 13(15), 2111; https://doi.org/10.3390/plants13152111 - 30 Jul 2024

Viewed by 852

Abstract

Drought stress is widely recognized as a highly detrimental abiotic stress factor that significantly impacts crop growth, development, and agricultural productivity. In response to external stimuli, plants activate various mechanisms to enhance their resistance or tolerance to abiotic stress. The common bean, a [...] Read more.

Drought stress is widely recognized as a highly detrimental abiotic stress factor that significantly impacts crop growth, development, and agricultural productivity. In response to external stimuli, plants activate various mechanisms to enhance their resistance or tolerance to abiotic stress. The common bean, a most important legume according to the FAO, serves as a staple food for millions of people worldwide, due to its rich protein, carbohydrate, and fiber content, concurrently, and water scarcity is the main factor limiting common bean production. The process of domestication and on-farm conservation has facilitated the development of genotypes with varying degrees of drought stress resistance. Consequently, using landraces as biological material in research can lead to the identification of variants with superior resistance qualities to abiotic stress factors, which can be effectively integrated into breeding programs. The central scope of this research was to find out if different geographic origins of common bean genotypes can determine distinct responses at various levels. Hence, several analyses were carried out to investigate responses to water scarcity in three common bean genotypes, M-2087 (from the Mesoamerican gene pool), A-1988 (from the Andean gene pool) and Lechinta, known for its high drought stress resistance. Plants were subjected to different water regimes, followed by optical assessment of the anatomical structure of the hypocotyl and epicotyl in each group; furthermore, the morphological, physiological, and biochemical parameters and molecular data (quantification of the relative expression of the thirteen genes) were assessed. The three experimental variants displayed distinct responses when subjected to 12 days of water stress. In general, the Lechinta genotype demonstrated the highest adaptability and drought resistance. The M-2087 landrace, originating from the Mesoamerican geographic basin, showed a lower resistance to water stress, compared to the A-1988 landrace, from the Andean basin. The achieved results can be used to scale up future research about the drought resistance of plants, analyzing more common bean landraces with distinct geographic origins (Mesoamerican/Andean), which can then be used in breeding programs. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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25 pages, 11256 KiB

Open AccessArticle

Effect of Persistent Salt Stress on the Physiology and Anatomy of Hybrid Walnut (Juglans major × Juglans regia) Seedlings

by Jiali Tang, Xinying Ji, Ao Li, Xu Zheng, Yutong Zhang and Junpei Zhang

Plants 2024, 13(13), 1840; https://doi.org/10.3390/plants13131840 - 4 Jul 2024

Viewed by 1036

Abstract

Soil salinization has become one of the major problems that threaten the ecological environment. The aim of this study is to explore the mechanism of salt tolerance of hybrid walnuts (Juglans major × Juglans regia) under long-term salt stress through the [...] Read more.

Soil salinization has become one of the major problems that threaten the ecological environment. The aim of this study is to explore the mechanism of salt tolerance of hybrid walnuts (Juglans major × Juglans regia) under long-term salt stress through the dynamic changes of growth, physiological and biochemical characteristics, and anatomical structure. Our findings indicate that (1) salt stress inhibited seedling height and ground diameter increase, and (2) with increasing salt concentration, relative water content (RWC) decreased, and proline (Pro) and soluble sugar (SS) content increased. The Pro content reached a maximum of 549.64 μg/g on the 42nd day. The increase in superoxide dismutase (SOD) activity (46.80–117.16%), ascorbate peroxidase (APX) activity, total flavonoid content (TFC), and total phenol content (TPC) under salt stress reduced the accumulation of malondialdehyde (MDA). (3) Increasing salt concentration led to increases and subsequent decreases in the thickness of palisade tissues, spongy tissues, leaves, and leaf vascular bundle diameter. Upper and lower skin thickness, root periderm thickness, root diameter, root cortex thickness, and root vascular bundle diameter showed different patterns of change at varying stress concentrations and durations. Overall, the study concluded that salt stress enhanced the antireactive oxygen system, increased levels of osmotic regulators, and low salt concentrations promoted leaf and root anatomy, but that under long-term exposure to high salt levels, leaf anatomy was severely damaged. For the first time, this study combined the anatomical structure of the vegetative organ of hybrid walnut with physiology and biochemistry, which is of great significance for addressing the challenge of walnut salt stress and expanding the planting area. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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18 pages, 10687 KiB

Open AccessArticle

Methyl-Sensitive Amplification Polymorphism (MSAP) Analysis Provides Insights into the DNA Methylation Changes Underlying Adaptation to Low Temperature of Brassica rapa L.

by Lijun Liu, Wanpeng Wang, Xiaoming Lu, Tianyu Zhang, Junyan Wu, Yan Fang, Li Ma, Yuanyuan Pu, Gang Yang, Wangtian Wang and Wancang Sun

Plants 2024, 13(13), 1748; https://doi.org/10.3390/plants13131748 - 24 Jun 2024

Cited by 1 | Viewed by 1102

Abstract

Background: DNA methylation can change rapidly to regulate the expression of stress-responsive genes. Previous studies have shown that there are significant differences in the cold resistance of winter rapeseed (Brassica rapa L.) after being domesticated in different selection environments; however, little is [...] Read more.

Background: DNA methylation can change rapidly to regulate the expression of stress-responsive genes. Previous studies have shown that there are significant differences in the cold resistance of winter rapeseed (Brassica rapa L.) after being domesticated in different selection environments; however, little is known about the epigenetic regulatory mechanisms of its cold resistance formation. Methods: Four winter rapeseed materials (‘CT-2360’, ‘MXW-1’, ‘2018-FJT’, and ‘DT-7’) domesticated in different environments were selected to analyze the DNA methylation level and pattern changes under low temperature using methylation-sensitive amplified polymorphism technology with 60 primer pairs. Results: A total of 18 pairs of primers with good polymorphism were screened, and 1426 clear bands were amplified, with 594 methylation sites, accounting for 41.65% of the total amplified bands. The total methylation ratios of the four materials were reduced after low-temperature treatment, in which the DNA methylation level of ‘CT-2360’ was higher than that of the other three materials; the analysis of methylation patterns revealed that the degree of demethylation was higher than that of methylation in ‘MXW-1’, ‘2018-FJT’, and ‘DT-7’, which were 22.99%, 19.77%, and 24.35%, respectively, and that the methylation events in ‘CT-2360’ were predominantly dominant at 22.95%. Fifty-three polymorphic methylated DNA fragments were randomly selected and further analyzed, and twenty-nine of the cloned fragments were homologous to genes with known functions. The candidate genes VQ22 and LOC103871127 verified the existence of different expressive patterns before and after low-temperature treatment. Conclusions: Our work implies the critical role of DNA methylation in the formation of cold resistance in winter rapeseed. These results provide a comprehensive insight into the adaptation epigenetic regulatory mechanism of Brassica rapa L. to low temperature, and the identified differentially methylated genes can also be used as important genetic resources for the multilateral breeding of winter-resistant varieties. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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18 pages, 6968 KiB

Open AccessArticle

Functional Characterization of the Soybean Glycine max Actin Depolymerization Factor GmADF13 for Plant Resistance to Drought Stress

by Deying Wang, Mengxue Du, Peng Lyu, Jingyu Li, Huiran Meng, Xinxin Liu, Mengmeng Shi, Yujie Gong, Qi Sha, Qingmei Men, Xiaofei Li, Yongwang Sun and Shangjing Guo

Plants 2024, 13(12), 1651; https://doi.org/10.3390/plants13121651 - 14 Jun 2024

Viewed by 1084

Abstract

Abiotic stress significantly affects plant growth and has devastating effects on crop production. Drought stress is one of the main abiotic stressors. Actin is a major component of the cytoskeleton, and actin-depolymerizing factors (ADFs) are conserved actin-binding proteins in eukaryotes that play critical [...] Read more.

Abiotic stress significantly affects plant growth and has devastating effects on crop production. Drought stress is one of the main abiotic stressors. Actin is a major component of the cytoskeleton, and actin-depolymerizing factors (ADFs) are conserved actin-binding proteins in eukaryotes that play critical roles in plant responses to various stresses. In this study, we found that GmADF13, an ADF gene from the soybean Glycine max, showed drastic upregulation under drought stress. Subcellular localization experiments in tobacco epidermal cells and tobacco protoplasts showed that GmADF13 was localized in the nucleus and cytoplasm. We characterized its biological function in transgenic Arabidopsis and hairy root composite soybean plants. Arabidopsis plants transformed with GmADF13 displayed a more robust drought tolerance than wild-type plants, including having a higher seed germination rate, longer roots, and healthy leaves under drought conditions. Similarly, GmADF13-overexpressing (OE) soybean plants generated via the Agrobacterium rhizogenes-mediated transformation of the hairy roots showed an improved drought tolerance. Leaves from OE plants showed higher relative water, chlorophyll, and proline contents, had a higher antioxidant enzyme activity, and had decreased malondialdehyde, hydrogen peroxide, and superoxide anion levels compared to those of control plants. Furthermore, under drought stress, GmADF13 OE activated the transcription of several drought-stress-related genes, such as GmbZIP1, GmDREB1A, GmDREB2, GmWRKY13, and GmANK114. Thus, GmADF13 is a positive regulator of the drought stress response, and it may play an essential role in plant growth under drought stress conditions. These results provide new insights into the functional elucidation of soybean ADFs. They may be helpful for breeding new soybean cultivars with a strong drought tolerance and further understanding how ADFs help plants adapt to abiotic stress. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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16 pages, 4318 KiB

Open AccessArticle

Frost Damage Mitigation in Flowers and Fruitlets of Peach and Almond from the Application of a Multi-Attribute Approach Biostimulant

by Estanis Torres and Xavier Miarnau

Plants 2024, 13(12), 1603; https://doi.org/10.3390/plants13121603 - 8 Jun 2024

Cited by 1 | Viewed by 898

Abstract

To prevent frost damage in fruit trees, growers employ passive and active methods, and one of these second methods is the use of biostimulant compounds against abiotic stress. In this study, two trials were conducted to evaluate the effectiveness of a multi-attribute approach [...] Read more.

To prevent frost damage in fruit trees, growers employ passive and active methods, and one of these second methods is the use of biostimulant compounds against abiotic stress. In this study, two trials were conducted to evaluate the effectiveness of a multi-attribute approach biostimulant—containing α-tocopherol, boron, and glycols, in peach (‘UFO-4’ cultivar) and almond (‘Vairo’ cultivar) trees. In a first trial, one-year-old shoots with flowers were collected after 24 h, 48 h, and 96 h of the biostimulant applications. Two different application rates of the product (1000 and 2000 cc ha⁻¹) were tested and compared to an untreated control. In a second trial, one-year-old shoots with fruitlets were collected after 24 h of the biostimulant applications. In this case, only an application rate (2000 cc ha⁻¹) was tested. In the two trials, the collected one-year-old shoots were subjected to different frost temperatures using a controlled environment chamber. The damage level was assessed by a morphological analysis of the flowers and fruitlets 96 h after each frost cycle simulation. The lethal temperatures (LT₁₀, LT₅₀, and LT₉₀) of each treatment were calculated by probit analysis. The product applied 24 h and 48 h before the frost simulations significantly decreased the LT₁₀ and LT₅₀ in 1.5 °C in peach flowers, and 2.5 °C in almond flowers (a temperature reduction of 50% and 75%, respectively). These results were more consistent when the application volume was 2000 cc ha⁻¹, instead of 1000 cc ha⁻¹. Significant differences between treated and non-treated fruitlets were observed only in almond fruitlets, with LT₁₀ and LT₅₀ being 0.5 °C lower in treated fruitlets (20% reduction). In conclusion, the multi-attribute approach biostimulant applied 24 or 48 h before the frost reduced the mortality of peach and almond flowers, but its effectiveness to protect fruitlets after bloom was inconsistent. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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17 pages, 4773 KiB

Open AccessArticle

Drought Resilience in Oil Palm Cultivars: A Multidimensional Analysis of Diagnostic Variables

by Cristihian Bayona-Rodríguez and Hernán Mauricio Romero

Plants 2024, 13(12), 1598; https://doi.org/10.3390/plants13121598 - 8 Jun 2024

Cited by 3 | Viewed by 1537

Abstract

Water scarcity is a significant constraint on agricultural practices, particularly in Colombia, where numerous palm cultivators rely on rainfed systems for their plantations. Identifying drought-tolerant cultivars becomes pivotal to mitigating the detrimental impacts of water stress on growth and productivity. This study scrutinizes [...] Read more.

Water scarcity is a significant constraint on agricultural practices, particularly in Colombia, where numerous palm cultivators rely on rainfed systems for their plantations. Identifying drought-tolerant cultivars becomes pivotal to mitigating the detrimental impacts of water stress on growth and productivity. This study scrutinizes the variability in drought responses of growth, physiological, and biochemical variables integral to selecting drought-tolerant oil palm cultivars in the nursery. A comprehensive dataset was compiled by subjecting seedlings of eleven cultivars to four soil water potentials (−0.05 MPa, −0.5 MPa, −1 MPa, and −2 MPa) over 60 days. This dataset encompasses growth attributes, photosynthetic parameters like maximum quantum yield and electron transfer rate, gas exchange (photosynthesis, transpiration, and water use efficiency), levels of osmolytes (proline and sugars), abscisic acid (ABA) content, as well as antioxidant-related enzymes, including peroxidase, catalase, ascorbate peroxidase, glutathione reductase, and superoxide dismutase. Principal Component Analysis (PCA) elucidated two principal components that account for approximately 65% of the cumulative variance. Noteworthy enzyme activity was detected for glutathione reductase and ascorbate peroxidase. When juxtaposed with the other evaluated cultivars, one of the cultivars (IRHO 7001) exhibited the most robust response to water deficit. The six characteristics evaluated (photosynthesis, predawn water potential, proline, transpiration, catalase activity, sugars) were determined to be the most discriminant when selecting palm oil cultivars with tolerance to water deficit. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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14 pages, 10954 KiB

Open AccessArticle

Effects of Foliar Boron Application on Physiological and Antioxidants Responses in Highbush Blueberry (Vaccinium corymbosum L.) Cultivars

by Marjorie Reyes-Díaz, Paz Cárcamo-Fincheira, Ricardo Tighe-Neira, Adriano Nunes-Nesi, Arnould Savouré and Claudio Inostroza-Blancheteau

Plants 2024, 13(11), 1553; https://doi.org/10.3390/plants13111553 - 4 Jun 2024

Viewed by 952

Abstract

Boron (B) is a micronutrient crucial for the growth, development, productivity, and quality of crops. However, in areas characterized by acid soil (pH_water < 5.0) and high rainfall, soil B concentration tends to decrease, leading to insufficient supply to crops. This study [...] Read more.

Boron (B) is a micronutrient crucial for the growth, development, productivity, and quality of crops. However, in areas characterized by acid soil (pH_water < 5.0) and high rainfall, soil B concentration tends to decrease, leading to insufficient supply to crops. This study was aimed at determining the optimal rate of B fertilization to enhance Vaccinium corymbosum L. performance in acid conditions. One-year-old cultivars with contrasting Al resistance (Al-sensitive Star and Al-resistant Cargo) were used. Plants were conditioned in plastic pots containing 18 L of half-ionic-strength Hoagland solution (pH 4.5) for 2 weeks. Thereafter, the following B treatments were applied foliarly: control, without B application (distilled water), 200, 400, and 800 mg L⁻¹ of B as Solubor^® for up to 72 h. Photosynthetic performance, root and shoot B levels, antioxidants, and oxidative stress were evaluated. Root and shoot B concentrations increased with the increasing B application, being higher in leaves than in roots of both cultivars. Net photosynthesis decreased at 800 mg L⁻¹ B supply and effective quantum yield of PSII at 72 h in all B treatments. Lipid peroxidation increased in both cultivars at 800 mg L⁻¹ B treatment. Antioxidant activity increased in all B treatments in both cultivars; while, at 400 and 800 mg L⁻¹ B, total phenols increased in leaves of cultivar Star and decreased in cultivar Cargo. In conclusion, optimal B foliar application for highbush blueberry appears to be around 400 mg L⁻¹ B. The appropriate B foliar application could help mitigate potential stress-induced problems in highbush blueberry cultivation. However, the optimal foliar B application should be confirmed in field experiments to help the farmers manage B nutrition. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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19 pages, 3621 KiB

Open AccessArticle

Au-Based Nanoparticles Enhance Low Temperature Tolerance in Wheat by Regulating Some Physiological Parameters and Gene Expression

by Yuliya Venzhik, Alexander Deryabin and Kseniya Zhukova

Plants 2024, 13(9), 1261; https://doi.org/10.3390/plants13091261 - 30 Apr 2024

Cited by 1 | Viewed by 1642

Abstract

One of the key problems of biology is how plants adapt to unfavorable conditions, such as low temperatures. A special focus is placed on finding ways to increase tolerance in important agricultural crops like wheat. Au-based nanoparticles (Au-NPs) have been employed extensively in [...] Read more.

One of the key problems of biology is how plants adapt to unfavorable conditions, such as low temperatures. A special focus is placed on finding ways to increase tolerance in important agricultural crops like wheat. Au-based nanoparticles (Au-NPs) have been employed extensively in this area in recent years. Au-NPs can be produced fast and easily using low-cost chemical reagents. When employed in microdoses, Au-NPs are often non-toxic to plants, animals, and people. In addition, Au-NPs mainly have favorable impacts on plants. In this study, we investigated the effect of Au-NP seed nanopriming (diameter 15.3 nm, Au concentration 5–50 µg mL⁻¹) on cold tolerance, as well as some physiological, biochemical and molecular parameters, of cold-sustainable wheat (Triticum aestivum L.) genotype Zlata. The treatment with Au-NPs improved tolerance to low temperatures in control conditions and after cold hardening. Au-NPs treatment boosted the intensity of growth processes, the quantity of photosynthetic pigments, sucrose in leaves, and the expressions of encoded RuBisCo and Wcor15 genes. The potential mechanisms of Au-NPs’ influence on the cold tolerance of wheat varieties were considered. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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24 pages, 5235 KiB

Open AccessArticle

Alterations of Photosynthetic and Oxidative Processes Influenced by the Presence of Different Zinc and Cadmium Concentrations in Maize Seedlings: Transition from Essential to Toxic Functions

by Ildikó Jócsák, Ferenc Csima and Katalin Somfalvi-Tóth

Plants 2024, 13(8), 1150; https://doi.org/10.3390/plants13081150 - 20 Apr 2024

Cited by 1 | Viewed by 1155

Abstract

Background: The study examined the impact of varying the concentrations of zinc (Zn) on plant responses, particularly on photosynthetic and oxidative metabolic processes. This investigation aimed to distinguish between the beneficial and harmful effects of Zn on plants, highlighting significant nutrient supply concerns. [...] Read more.

Background: The study examined the impact of varying the concentrations of zinc (Zn) on plant responses, particularly on photosynthetic and oxidative metabolic processes. This investigation aimed to distinguish between the beneficial and harmful effects of Zn on plants, highlighting significant nutrient supply concerns. Methods: The investigation methods were centered around non-invasive methods, such as biophoton emission (delayed fluorescence—DF, ultra-weak bioluminescence—UWLE), fluorescence induction (F_v/F_m) measurements, chlorophyll content estimation (SPAD) and vegetation index (NDVI) determination. Furthermore, the analytical determination of lipid oxidation (MDA level) and antioxidant capacity (FRAP) as well as gene expression studies of the antioxidative enzymes glutathione reductase (GR), glutathione S-transferase (GST) and lipoxygenase (LOX) for essential Zn and nonessential cadmium (Cd) were also carried out in order to clarify toxic symptoms through different Zn investigation approaches. Results: It was possible to identify a metabolic enhancement from 1000 µM; however, stress symptoms from the 2000 µM Zn treatment were noted for both the investigated photosynthetic and oxidative processes. The outcomes of this research contribute to the improvement of Zn mineral-supplementation technology, which is essential for maize growth, and the optimization of agricultural practices. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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17 pages, 3668 KiB

Open AccessArticle

Changes in Growth and Heavy Metal and Phenolic Compound Accumulation in Buddleja cordata Cell Suspension Culture under Cu, Fe, Mn, and Zn Enrichment

by Alicia Monserrat Vazquez-Marquez, Antonio Bernabé-Antonio, José Correa-Basurto, Cristina Burrola-Aguilar, Carmen Zepeda-Gómez, Francisco Cruz-Sosa, Aurelio Nieto-Trujillo and María Elena Estrada-Zúñiga

Plants 2024, 13(8), 1147; https://doi.org/10.3390/plants13081147 - 19 Apr 2024

Cited by 1 | Viewed by 1229

Abstract

Buddleja cordata cell suspension cultures could be used as a tool for investigating the capabilities of this species to tolerate heavy metals (HMs) and for assessing the effects of HMs on the accumulation of phenolic compounds in this species. It grows in a [...] Read more.

Buddleja cordata cell suspension cultures could be used as a tool for investigating the capabilities of this species to tolerate heavy metals (HMs) and for assessing the effects of HMs on the accumulation of phenolic compounds in this species. It grows in a wide range of habitats in Mexico, including ultramafic soils, and mobilizes some HMs in the soil. The mobilization of these HMs has been associated with phenolic substances. In addition, this species is used in Mexican traditional medicine. In the present study, a B. cordata cell suspension culture was grown for 18 days in a culture medium enriched with Cu (0.03–0.25 mM), Fe (0.25–1.5 mM), Mn (0.5–3.0 mM), or Zn (0.5–2.0 mM) to determine the effects of these HMs on growth and HM accumulation. We also assessed the effects of the HMs on phenolic compound accumulation after 1 and 18 days of HM exposure. Cells were able to grow at almost all tested HM concentrations and accumulated significant amounts of each HM. The highest accumulation levels were as follows: 1160 mg Cu kg⁻¹, 6845 mg Fe kg⁻¹, 3770 mg Mn kg⁻¹, and 6581 mg Zn kg⁻¹. Phenolic compound accumulation was affected by the HM exposure time and corresponded to each HM and its concentration. Future research should analyze whole plants to determine the capabilities of Buddleja cordata to accumulate abnormally high amounts of HM and to evaluate the physiological impact of changes in the accumulation of phenolic compounds. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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20 pages, 2854 KiB

Open AccessArticle

Copper Oxide Nanoparticles Induced Growth and Physio-Biochemical Changes in Maize (Zea mays L.) in Saline Soil

by Hina Shafiq, Muhammad Yousaf Shani, Muhammad Yasin Ashraf, Francesco De Mastro, Claudio Cocozza, Shahid Abbas, Naila Ali, Zaib-un-Nisa, Aqsa Tahir, Muhammad Iqbal, Zafran Khan, Nimra Gul and Gennaro Brunetti

Plants 2024, 13(8), 1080; https://doi.org/10.3390/plants13081080 - 11 Apr 2024

Cited by 4 | Viewed by 1700

Abstract

Research on nanoparticles (NPs) is gaining great attention in modulating abiotic stress tolerance and improving crop productivity. Therefore, this investigation was carried out to evaluate the effects of copper oxide nanoparticles (CuO-NPs) on growth and biochemical characteristics in two maize hybrids (YH-5427 and [...] Read more.

Research on nanoparticles (NPs) is gaining great attention in modulating abiotic stress tolerance and improving crop productivity. Therefore, this investigation was carried out to evaluate the effects of copper oxide nanoparticles (CuO-NPs) on growth and biochemical characteristics in two maize hybrids (YH-5427 and FH-1046) grown under normal conditions or subjected to saline stress. A pot-culture experiment was carried out in the Botanical Research Area of “the University of Lahore”, Lahore, Pakistan, in a completely randomized design. At two phenological stages, both maize hybrids were irrigated with the same amount of distilled water or NaCl solution (EC = 5 dS m⁻¹) and subjected or not to foliar treatment with a suspension of CuO-NPs. The salt stress significantly reduced the photosynthetic parameters (photosynthetic rate, transpiration, stomatal conductance), while the sodium content in the shoot and root increased. The foliar spray with CuO-NPs improved the growth and photosynthetic attributes, along with the N, P, K, Ca, and Mg content in the roots and shoots. However, the maize hybrid YH-5427 responded better than the other hybrid to the saline stress when sprayed with CuO-NPs. Overall, the findings of the current investigation demonstrated that CuO-NPs can help to reduce the adverse effects of salinity stress on maize plants by improving growth and physio-biochemical attributes. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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17 pages, 4222 KiB

Open AccessArticle

Determination of Morpho-Physiological Traits for Assessing Drought Tolerance in Sugarcane

by Warodom Wirojsirasak, Patcharin Songsri, Nakorn Jongrungklang, Sithichoke Tangphatsornruang, Peeraya Klomsa-ard and Kittipat Ukoskit

Plants 2024, 13(8), 1072; https://doi.org/10.3390/plants13081072 - 11 Apr 2024

Cited by 3 | Viewed by 1253

Abstract

Drought is a significant constraint to sugarcane productivity. Therefore, understanding how different varieties of sugarcane respond to drought stress can facilitate breeding programs and set up criteria for selecting drought-tolerant varieties. In the present study, we examined eight morpho-physiological traits to distinguish 40 [...] Read more.

Drought is a significant constraint to sugarcane productivity. Therefore, understanding how different varieties of sugarcane respond to drought stress can facilitate breeding programs and set up criteria for selecting drought-tolerant varieties. In the present study, we examined eight morpho-physiological traits to distinguish 40 sugarcane genotypes categorized into four groups based on significant differences in cane yield under non-stressed conditions and reduction of cane yield under drought-stressed conditions. The study was conducted during the formative stage in a greenhouse, encompassing both control and drought conditions. Drought treatments resulted in significant changes and differences in the mean values of various morpho-physiological traits. The hierarchical clustering analysis, utilizing stay-green traits such as higher chlorophyll fluorescence ratio (F_v/F_m), leaf chlorophyll content (SPAD), leaf relative water content (RWC), and lower leaf rolling score (LR), leaf drying score (LD), and drought recovery score (DR), successfully grouped 40 sugarcane genotypes into four major clusters, similar to the previously categorized groups. Correlation analysis showed significant relationships among cane yield, reduction of cane yield under drought conditions, and the stay-green traits. Our results demonstrated that morpho-physiological traits contributing to the “stay-green” phenotypes could be useful as selection criteria for drought tolerance in sugarcane. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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15 pages, 9048 KiB

Open AccessArticle

Relative Water Content, Chlorophyll Index, and Photosynthetic Pigments on Lotus corniculatus L. in Response to Water Deficit

by Luis Ángel González-Espíndola, Aurelio Pedroza-Sandoval, Ricardo Trejo-Calzada, María del Rosario Jacobo-Salcedo, Gabino García de los Santos and Jesús Josafath Quezada-Rivera

Plants 2024, 13(7), 961; https://doi.org/10.3390/plants13070961 - 26 Mar 2024

Cited by 2 | Viewed by 1866

Abstract

This study aimed to evaluate different L. corniculatus L. ecotypes under water-deficit conditions to identify changes in relative water content and photosynthetic pigments as indicators of physiological responses during different years’ seasons. The experiment was conducted in a randomized block design with three [...] Read more.

This study aimed to evaluate different L. corniculatus L. ecotypes under water-deficit conditions to identify changes in relative water content and photosynthetic pigments as indicators of physiological responses during different years’ seasons. The experiment was conducted in a randomized block design with three replicates. Ten treatments were performed as a factorial of 2 × 5, where the first variation factor was the soil water content—no water deficit (NDW) with 100% field capacity (FC), and water deficit (DW) corresponding to 85.4% of the FC—and the second variation factor comprised four ecotypes and one variety of L. corniculatus. A significant effect was identified on the concentration of photosynthetic pigments, mainly total chlorophyll, with chlorophyll a in the 255301 ecotype with records of 187.8, 167.5, and 194.6 mg g⁻¹ FW in WD, corresponding to an increase of 86.0%, 172.6%, and 16.6%, respectively, in relation the lower values obtained in the ecotype 202700 under NWD. In carotenoids, higher concentrations were observed in the 255301 and 202700 ecotypes and the Estanzuela Ganador variety under WD in most seasonal periods, except summer; a similar response was found in the 202700 ecotype and the Estanzuela Ganador variety during the winter season, also in WD. The results showed that the first two principal components accounted for 71.8% of the total variation, with PC1 representing chlorophyll a, chlorophyll b, and total chlorophyll, and PC2 representing carotenoids, temperature, relative chlorophyll index, and relative water content. The observations were grouped based on soil moisture content, with the optimal moisture group exhibiting higher chlorophyll and carotenoid concentrations. The findings suggest that soil moisture content significantly affects the performance of L. corniculatus ecotypes, and the plant shows seasonal variations in response to water-deficit conditions. This research contributes to understanding the physiological responses of L. corniculatus and its potential as a water-efficient forage crop for promoting sustainable agriculture and enhancing food security. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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15 pages, 1442 KiB

Open AccessArticle

Mycorrhizas Affect Physiological Performance, Antioxidant System, Photosynthesis, Endogenous Hormones, and Water Content in Cotton under Salt Stress

by De-Jian Zhang, Cui-Ling Tong, Qiong-Shan Wang and Shu Bie

Plants 2024, 13(6), 805; https://doi.org/10.3390/plants13060805 - 12 Mar 2024

Cited by 8 | Viewed by 1292

Abstract

Saline–alkali stress seriously endangers the normal growth of cotton (Gossypium hirsutum). Arbuscular mycorrhizal fungi (AMF) could enhance salt tolerance by establishing symbiotic relationships with plants. Based on it, a pot experiment was conducted to simulate a salt environment in which cotton [...] Read more.

Saline–alkali stress seriously endangers the normal growth of cotton (Gossypium hirsutum). Arbuscular mycorrhizal fungi (AMF) could enhance salt tolerance by establishing symbiotic relationships with plants. Based on it, a pot experiment was conducted to simulate a salt environment in which cotton was inoculated with Paraglomus occultum to explore its effects on the saline–alkali tolerance of cotton. Our results showed that salt stress noticeably decreased cotton seedling growth parameters (such as plant height, number of leaves, dry weight, root system architecture, etc.), while AMF exhibited a remarkable effect on promoting growth. It was noteworthy that AMF significantly mitigated the inhibitory effect of salt on cotton seedlings. However, AMF colonization in root and soil hyphal length were collectively descended via salt stress. With regard to osmotic regulating substances, Pro and MDA values in roots were significantly increased when seedlings were exposed to salt stress, while AMF only partially mitigated these reactions. Salt stress increased ROS levels in the roots of cotton seedlings and enhanced antioxidant enzyme activity (SOD, POD, and CAT), while AMF mitigated the increases in ROS levels but further strengthened antioxidant enzyme activity. AMF inoculation increased the photosynthesis parameters of cotton seedling leaves to varying degrees, while salt stress decreased them dramatically. When inoculated with AMF under a salt stress environment, only partial mitigation of these photosynthesis values was observed. Under saline–alkali stress, AMF improved the leaf fluorescence parameters (φPSII, Fv′/Fm′, and qP) of cotton seedlings, leaf chlorophyll levels, and root endogenous hormones (IAA and BR); promoted the absorption of water; and maintained nitrogen balance, thus alleviating the damage from salt stress on the growth of cotton plants to some extent. In summary, mycorrhizal cotton seedlings may exhibit mechanisms involving root system architecture, the antioxidant system, photosynthesis, leaf fluorescence, endogenous hormones, water content, and nitrogen balance that increase their resistance to saline–alkali environments. This study provide a theoretical basis for further exploring the application of AMF to enhance the salt tolerance of cotton. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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20 pages, 5389 KiB

Open AccessArticle

Foliar Application of Amino Acids and Nutrients as a Tool to Mitigate Water Stress and Stabilize Sugarcane Yield and Bioenergy Generation

by Lucas Moraes Jacomassi, Marcela Pacola, Letusa Momesso, Josiane Viveiros, Osvaldo Araújo Júnior, Gabriela Ferraz de Siqueira, Murilo de Campos and Carlos Alexandre Costa Crusciol

Plants 2024, 13(3), 461; https://doi.org/10.3390/plants13030461 - 5 Feb 2024

Cited by 2 | Viewed by 2398

Abstract

Extended periods of water stress negatively affect sugarcane crop production. The foliar application of supplements containing specific nutrients and/or organic molecules such as amino acids can improve sugarcane metabolism, stalk and sugar yields, and the quality of the extracted juice. The present study [...] Read more.

Extended periods of water stress negatively affect sugarcane crop production. The foliar application of supplements containing specific nutrients and/or organic molecules such as amino acids can improve sugarcane metabolism, stalk and sugar yields, and the quality of the extracted juice. The present study assessed the effectiveness of the foliar application of an abiotic stress protection complement (ASPC) composed of 18 amino acids and 5 macronutrients. The experiments were carried out in the field with two treatments and twelve replicates. The two treatments were no application of ASPC (control) and foliar application of ASPC. The foliar application of ASPC increased the activity of antioxidant enzymes. The Trolox-equivalent antioxidant capacity (DPPH) was higher in ASPC-treated plants than in control plants, reflecting higher antioxidant enzyme activity and lower malondialdehyde (MDA) levels. The level of H₂O₂ was 11.27 nM g⁻¹ protein in plants treated with ASPC but 23.71 nM g⁻¹ protein in control plants. Moreover, the application of ASPC increased stalk yield and sucrose accumulation, thus increasing the quality of the raw material. By positively stabilizing the cellular redox balance in sugarcane plants, ASPC application also increased energy generation. Therefore, applying ASPC is an effective strategy for relieving water stress while improving crop productivity. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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21 pages, 8803 KiB

Open AccessArticle

Psammophytes Alyssum desertorum Stapf and Secale sylvestre Host Are Sensitive to Soil Flooding

by Elizabeth Kordyum, Yuri Akimov, Oleksandr Polishchuk, Ihor Panas, Sergiy Stepanov and Liudmyla Kozeko

Plants 2024, 13(3), 413; https://doi.org/10.3390/plants13030413 - 30 Jan 2024

Cited by 1 | Viewed by 1146

Abstract

While morphological and functional traits enable hydrophytes to survive under waterlogging and partial or complete submergence, the data on responses of psammophytes—sand plants—to flooding are very limited. We analyzed the effect of 5- and 10-day soil flooding on the photosynthetic apparatus and the [...] Read more.

While morphological and functional traits enable hydrophytes to survive under waterlogging and partial or complete submergence, the data on responses of psammophytes—sand plants—to flooding are very limited. We analyzed the effect of 5- and 10-day soil flooding on the photosynthetic apparatus and the synthesis of alcohol dehydrogenase (ADH), heat shock proteins 70 (HSP70), and ethylene in seedlings of psammophytes Alyssum desertorum and Secale sylvestre using electron microscopy, chlorophyll a fluorescence induction, and biochemical methods. It was found that seedlings growing under soil flooding differed from those growing in stationary conditions with such traits as chloroplast ultrastructure, pigment content, chlorophyll fluorescence induction, and the dynamics of ADH, HSP, and ethylene synthesis. Although flooding caused no apparent damage to the photosynthetic apparatus in all the variants, a significant decrease in total photosynthesis efficiency was observed in both studied plants, as indicated by decreased values of φR0 and PI_ABS,total. More noticeable upregulation of ADH in S. sylvestre, as well as increasing HSP70 level and more intensive ethylene emission in A. desertorum, indicate species-specific differences in these traits in response to short-term soil flooding. Meanwhile, the absence of systemic anaerobic metabolic adaptation to prolonged hypoxia causes plant death. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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17 pages, 4957 KiB

Open AccessArticle

Nanopore Direct RNA Sequencing Reveals the Short-Term Salt Stress Response in Maize Roots

by Shidong He, Hui Wang, Minghao Lv, Shun Li, Junhui Song, Rongxin Wang, Shaolong Jiang, Lijun Jiang, Shuxin Zhang and Xiang Li

Plants 2024, 13(3), 405; https://doi.org/10.3390/plants13030405 - 30 Jan 2024

Cited by 1 | Viewed by 2167

Abstract

Transcriptome analysis, relying on the cutting-edge sequencing of cDNA libraries, has become increasingly prevalent within functional genome studies. However, the dependence on cDNA in most RNA sequencing technologies restricts their ability to detect RNA base modifications. To address this limitation, the latest Oxford [...] Read more.

Transcriptome analysis, relying on the cutting-edge sequencing of cDNA libraries, has become increasingly prevalent within functional genome studies. However, the dependence on cDNA in most RNA sequencing technologies restricts their ability to detect RNA base modifications. To address this limitation, the latest Oxford Nanopore Direct RNA Sequencing (ONT DRS) technology was employed to investigate the transcriptome of maize seedling roots under salt stress. This approach aimed to unveil both the RNA transcriptional profiles and alterations in base modifications. The analysis of the differential expression revealed a total of 1398 genes and 2223 transcripts that exhibited significant variation within the maize root system following brief exposure to salt stress. Enrichment analyses, such as the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway assessments, highlighted the predominant involvement of these differentially expressed genes (DEGs) in regulating ion homeostasis, nitrogen metabolism, amino acid metabolism, and the phytohormone signaling pathways. The protein–protein interaction (PPI) analysis showed the participation of various proteins related to glycolytic metabolism, nitrogen metabolism, amino acid metabolism, abscisic acid signaling, and the jasmonate signaling pathways. It was through this intricate molecular network that these proteins collaborated to safeguard root cells against salt-induced damage. Moreover, under salt stress conditions, the occurrence of variable shear events (AS) in RNA modifications diminished, the average length of poly(A) tails underwent a slight decrease, and the number of genes at the majority of the variable polyadenylation (APA) sites decreased. Additionally, the levels of N5-methylcytosine (m5C) and N6-methyladenosine (m6A) showed a reduction. These results provide insights into the mechanisms of early salt tolerance in maize. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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20 pages, 18287 KiB

Open AccessArticle

Characterization of the Heat Shock Transcription Factor Family in Lycoris radiata and Its Potential Roles in Response to Abiotic Stresses

by Ning Wang, Xiaochun Shu, Fengjiao Zhang, Guowei Song and Zhong Wang

Plants 2024, 13(2), 271; https://doi.org/10.3390/plants13020271 - 17 Jan 2024

Cited by 1 | Viewed by 1385

Abstract

Heat shock transcription factors (HSFs) are an essential plant-specific transcription factor family that regulates the developmental and growth stages of plants, their signal transduction, and their response to different abiotic and biotic stresses. The HSF gene family has been characterized and systematically observed [...] Read more.

Heat shock transcription factors (HSFs) are an essential plant-specific transcription factor family that regulates the developmental and growth stages of plants, their signal transduction, and their response to different abiotic and biotic stresses. The HSF gene family has been characterized and systematically observed in various species; however, research on its association with Lycoris radiata is limited. This study identified 22 HSF genes (LrHSFs) in the transcriptome-sequencing data of L. radiata and categorized them into three classes including HSFA, HSFB, and HSFC, comprising 10, 8, and 4 genes, respectively. This research comprises basic bioinformatics analyses, such as protein sequence length, molecular weight, and the identification of its conserved motifs. According to the subcellular localization assessment, most LrHSFs were present in the nucleus. Furthermore, the LrHSF gene expression in various tissues, flower developmental stages, two hormones stress, and under four different abiotic stresses were characterized. The data indicated that LrHSF genes, especially LrHSF5, were essentially involved in L. radiata development and its response to different abiotic and hormone stresses. The gene–gene interaction network analysis revealed the presence of synergistic effects between various LrHSF genes’ responses against abiotic stresses. In conclusion, these results provided crucial data for further functional analyses of LrHSF genes, which could help successful molecular breeding in L. radiata. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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11 pages, 2959 KiB

Open AccessCommunication

Species Survey of Leaf Hyponasty Responses to Warming Plus Elevated CO₂

by Michael D. Thomas, Reagan Roberts, Scott A. Heckathorn and Jennifer K. Boldt

Plants 2024, 13(2), 204; https://doi.org/10.3390/plants13020204 - 11 Jan 2024

Viewed by 1284

Abstract

Atmospheric carbon dioxide (CO₂) concentrations are increasing and may exceed 800 ppm by 2100. This is increasing global mean temperatures and the frequency and severity of heatwaves. Recently, we showed for the first time that the combination of short-term warming and [...] Read more.

Atmospheric carbon dioxide (CO₂) concentrations are increasing and may exceed 800 ppm by 2100. This is increasing global mean temperatures and the frequency and severity of heatwaves. Recently, we showed for the first time that the combination of short-term warming and elevated carbon dioxide (eCO₂) caused extreme upward bending (i.e., hyponasty) of leaflets and leaf stems (petioles) in tomato (Solanum lycopersicum), which reduced growth. Here, we examined additional species to test the hypotheses that warming + eCO₂-induced hyponasty is restricted to compound-leaved species, and/or limited to the Solanaceae. A 2 × 2 factorial experiment with two temperatures, near-optimal and supra-optimal, and two CO₂ concentrations, ambient and elevated (400, 800 ppm), was imposed on similarly aged plants for 7–10 days, after which final petiole angles were measured. Within Solanaceae, compound-leaf, but not simple-leaf, species displayed increased hyponasty with the combination of warming + eCO₂ relative to warming or eCO₂ alone. In non-solanaceous species, hyponasty, leaf-cupping, and changes in leaf pigmentation as a result of warming + eCO₂ were variable across species. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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27 pages, 28232 KiB

Open AccessArticle

Salt Stress Induces Contrasting Physiological and Biochemical Effects on Four Elite Date Palm Cultivars (Phoenix dactylifera L.) from Southeast Morocco

by Ibtissame Benaceur, Reda Meziani, Jamal El Fadile, Jan Hoinkis, Edgardo Canas Kurz, Ulrich Hellriegel and Fatima Jaiti

Plants 2024, 13(2), 186; https://doi.org/10.3390/plants13020186 - 10 Jan 2024

Cited by 2 | Viewed by 1410

Abstract

Understanding the response of date palm (Phoenix dactylifera L.) cultivars to salt stress is essential for the sustainable management of phoeniculture in Tafilalet, Morocco. It offers a promising avenue for addressing the challenges presented by the increasing salinity of irrigation waters, especially [...] Read more.

Understanding the response of date palm (Phoenix dactylifera L.) cultivars to salt stress is essential for the sustainable management of phoeniculture in Tafilalet, Morocco. It offers a promising avenue for addressing the challenges presented by the increasing salinity of irrigation waters, especially because farmers in these regions often lack the necessary knowledge and resources to make informed decisions regarding cultivar selection. This study addresses this issue by investigating the performance of the most relied on cultivars by farmers in Tafilalet, namely Mejhoul, Boufeggous, Nejda, and Bouskri. These cultivars were exposed to a sodium chloride treatment of 154 mM, and their performances were evaluated over a three-month period. We examined the growth rate, photosynthesis-related parameters, pigments, water status in plants, and biochemical compounds associated with oxidative stress, osmotic stress, and ionic stress. Principle component analysis (PCA) effectively categorized the cultivars into two distinct groups: salt-sensitive (Mejhoul and Nejda) and salt-tolerant (Boufeggous and Bouskri). These findings provide valuable insights for farmers, highlighting the advantages of cultivating Boufeggous and Bouskri cultivars due to their superior adaptation to salt conditions. These cultivars exhibited moderate decrease in shoot growth (25%), enhanced catalase activity, a smaller increase in anthocyanin content, and greater enhancement in organic osmolytes compared with salt-sensitive cultivars like Mejhoul (experiencing an 87% reduction in shoot elongation) and Nejda (exhibiting the highest reduction in leaf area). Furthermore, the Na⁺/K⁺ ratio was positively influenced by salt stress, with Mejhoul and Nejda recording the highest values, suggesting its potential as an indicator of salt stress sensitivity in date palms. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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Graphical abstract

17 pages, 5135 KiB

Open AccessArticle

Characterization and Identification of Drought-Responsive ABA-Aldehyde Oxidase (AAO) Genes in Potato (Solanum tuberosum L.)

by Panfeng Yao, Chunli Zhang, Dan Zhang, Tianyuan Qin, Xiaofei Xie, Yuhui Liu, Zhen Liu, Jiangping Bai, Zhenzhen Bi, Junmei Cui, Jingwen Liang and Chao Sun

Plants 2023, 12(22), 3809; https://doi.org/10.3390/plants12223809 - 9 Nov 2023

Viewed by 2082

Abstract

Abscisic acid (ABA) is an important stress hormone that affects plants’ tolerance to stress. Changes in the content of abscisic can have an impact on plant responses to abiotic stress. The abscisic acid aldehyde oxidase (AAO) plays a crucial role in the final [...] Read more.

Abscisic acid (ABA) is an important stress hormone that affects plants’ tolerance to stress. Changes in the content of abscisic can have an impact on plant responses to abiotic stress. The abscisic acid aldehyde oxidase (AAO) plays a crucial role in the final step in the synthesis of abscisic acid; therefore, understanding the function of the AAO gene family is of great significance for insight into plants’ response to abiotic stresses. In this study, Solanum tuberosum AAO (StAAO) members were exhaustively explored using genome databases, and nine StAAOs were identified. Chromosomal location analysis indicated that StAAO genes mapped to 4 of the 14 potato chromosomes. Further analyses of gene structure and motif composition showed that members of the specific StAAO subfamily showed relatively conserved characteristics. Phylogenetic relationship analysis indicated that StAAOs proteins were divided into three major clades. Promoter analysis showed that most StAAO promoters contained cis-elements related to abiotic stress response and plant hormones. The results of tissue-specific expression analysis indicated that StAAO4 was predominantly expressed in the roots. Analysis of transcriptome data revealed that StAAO2/4/6 genes responded significantly to drought treatments. Moreover, further qRT-PCR analysis results indicated that StAAO2/4/6 not only significantly responded to drought stress but also to various phytohormone (ABA, SA, and MeJA) and abiotic stresses (salt and low temperature), albeit with different expression patterns. In summary, our study provides comprehensive insights into the sequence characteristics, structural properties, evolutionary relationships, and expression patterns of the StAAO gene family. These findings lay the foundation for a deeper understanding of the StAAO gene family and offer a potential genetic resource for breeding drought-resistant potato varieties. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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20 pages, 7688 KiB

Open AccessArticle

Genome-Wide Identification and Characterization of the bHLH Gene Family and Its Response to Abiotic Stresses in Carthamus tinctorius

by Zhengwei Tan, Dandan Lu, Yongliang Yu, Lei Li, Wei Dong, Lanjie Xu, Qing Yang, Xiufu Wan and Huizhen Liang

Plants 2023, 12(21), 3764; https://doi.org/10.3390/plants12213764 - 3 Nov 2023

Viewed by 1681

Abstract

The basic helix–loop–helix (bHLH) transcription factors possess DNA-binding and dimerization domains and are involved in various biological and physiological processes, such as growth and development, the regulation of secondary metabolites, and stress response. However, the bHLH gene family in C. tinctorius has not [...] Read more.

The basic helix–loop–helix (bHLH) transcription factors possess DNA-binding and dimerization domains and are involved in various biological and physiological processes, such as growth and development, the regulation of secondary metabolites, and stress response. However, the bHLH gene family in C. tinctorius has not been investigated. In this study, we performed a genome-wide identification and analysis of bHLH transcription factors in C. tinctorius. A total of 120 CtbHLH genes were identified, distributed across all 12 chromosomes, and classified into 24 subfamilies based on their phylogenetic relationships. Moreover, the 120 CtbHLH genes were subjected to comprehensive analyses, including protein sequence alignment, evolutionary assessment, motif prediction, and the analysis of promoter cis-acting elements. The promoter region analysis revealed that CtbHLH genes encompass cis-acting elements and were associated with various aspects of plant growth and development, responses to phytohormones, as well as responses to both abiotic and biotic stresses. Expression profiles, sourced from transcriptome databases, indicated distinct expression patterns among these CtbHLH genes, which appeared to be either tissue-specific or specific to certain cultivars. To further explore their functionality, we determined the expression levels of fifteen CtbHLH genes known to harbor motifs related to abiotic and hormone responses. This investigation encompassed treatments with ABA, salt, drought, and MeJA. The results demonstrated substantial variations in the expression patterns of CtbHLH genes in response to these abiotic and hormonal treatments. In summary, our study establishes a solid foundation for future inquiries into the roles and regulatory mechanisms of the CtbHLH gene family. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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18 pages, 2880 KiB

Open AccessArticle

The Influence of Cadmium on Fountain Grass Performance Correlates Closely with Metabolite Profiles

by Zhaorong Mi, Pinlin Liu, Lin Du, Tao Han, Chao Wang, Xifeng Fan, Huichao Liu, Songlin He and Juying Wu

Plants 2023, 12(21), 3713; https://doi.org/10.3390/plants12213713 - 29 Oct 2023

Cited by 2 | Viewed by 1304

Abstract

The relationship between metabolite changes and biological endpoints in response to cadmium (Cd) stress remains unclear. Fountain grass has good Cd enrichment and tolerance abilities and is widely used in agriculture and landscaping. We analyzed the metabolic responses by detecting the metabolites through [...] Read more.

The relationship between metabolite changes and biological endpoints in response to cadmium (Cd) stress remains unclear. Fountain grass has good Cd enrichment and tolerance abilities and is widely used in agriculture and landscaping. We analyzed the metabolic responses by detecting the metabolites through UPLC-MS and examined the relationships between metabolite changes and the characteristics of morphology and physiology to different Cd stress in fountain grass. Our results showed that under Cd stress, 102 differential metabolites in roots and 48 differential metabolites in leaves were detected, with 20 shared metabolites. Under Cd stress, most of the carbohydrates in leaves and roots decreased, which contributed to the lowered leaf/root length and fresh weight. In comparison, most of the differential amino acids and lipids decreased in the leaves but increased in the roots. Almost all the differential amino acids in the roots were negatively correlated with root length and root fresh weight, while they were positively correlated with malondialdehyde content. However, most of the differential amino acids in the leaves were positively correlated with leaf length and leaf fresh weight but negatively correlated with malondialdehyde content. Metabolic pathway analysis showed that Cd significantly affects seven and eight metabolic pathways in the leaves and roots, respectively, with only purine metabolism co-existing in the roots and leaves. Our study is the first statement on metabolic responses to Cd stress and the relationships between differential metabolites and biological endpoints in fountain grass. The coordination between various metabolic pathways in fountain grass enables plants to adapt to Cd stress. This study provides a comprehensive framework by explaining the metabolic plasticity and Cd tolerance mechanisms of plants. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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16 pages, 5680 KiB

Open AccessArticle

Coordination of m⁶A mRNA Methylation and Gene Transcriptome in Sugarcane Response to Drought Stress

by Jinju Wei, Haibi Li, Yiyun Gui, Hui Zhou, Ronghua Zhang, Kai Zhu and Xihui Liu

Plants 2023, 12(21), 3668; https://doi.org/10.3390/plants12213668 - 24 Oct 2023

Viewed by 1507

Abstract

The N⁶-methyladenosine (m⁶A) methylation of mRNA is involved in biological processes essential for plant growth. To explore the m⁶A modification of sugarcane and reveal its regulatory function, methylated RNA immunoprecipitation sequencing (MeRIP-seq) was used to construct the [...] Read more.

The N⁶-methyladenosine (m⁶A) methylation of mRNA is involved in biological processes essential for plant growth. To explore the m⁶A modification of sugarcane and reveal its regulatory function, methylated RNA immunoprecipitation sequencing (MeRIP-seq) was used to construct the m⁶A map of sugarcane. In this study, m⁶A sites of sugarcane transcriptome were significantly enriched around the stop codon and within 3′-untranslated regions (3′UTR). Gene ontology (GO) analysis showed that the m⁶A modification genes are associated with metabolic biosynthesis. In addition, the m⁶A modification of drought-resistant transcript mRNA increased significantly under drought (DR) treatment, resulting in enhanced mRNA stability, which is involved in regulating sugarcane drought resistance. GO and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results showed that differentially methylated peak (DMP) modification of differentially expressed genes (DEGs) in DR were particularly associated with abscisic acid (ABA) biosynthesis. The upregulated genes were significantly enriched in the ABA metabolism, ethylene response, fatty acid metabolism, and negative regulation of the abscisic acid activation signaling pathway. These findings provide a basis and resource for sugarcane RNA epigenetic studies and further increase our knowledge of the functions of m⁶A modifications in RNA under abiotic stress. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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18 pages, 3271 KiB

Open AccessArticle

Effect of Different Rootstocks on the Salt Stress Tolerance and Fruit Quality of Grafted Eggplants (Solanum melongena L.)

by Maryam Mozafarian, Barbara Hawrylak-Nowak and Noémi Kappel

Plants 2023, 12(20), 3631; https://doi.org/10.3390/plants12203631 - 20 Oct 2023

Cited by 2 | Viewed by 1390

Abstract

Vegetable grafting is considered a rapid, non-chemical alternative method to relatively slow and expensive breeding to overcome the adverse effect of salinity. Therefore, a soilless experiment was performed to determine the salinity tolerance of eggplant (Solanum melongena) cv. Madonna grafted onto [...] Read more.

Vegetable grafting is considered a rapid, non-chemical alternative method to relatively slow and expensive breeding to overcome the adverse effect of salinity. Therefore, a soilless experiment was performed to determine the salinity tolerance of eggplant (Solanum melongena) cv. Madonna grafted onto two different rootstocks, Solanum grandifolium × Solanum melongena (SH) and Solanum torvum (ST), as well as self-grafted (SG) and self-rooted (SR) as controls. All groups of plants were treated with 0 mM NaCl or 80 mM NaCl. A significant decrease in the relative leaf chlorophyll content (SPAD value) and chlorophyll concentrations were found in response to NaCl. However, the grafted plants had a higher photosynthetic pigment level than the non-grafted plants grown under saline conditions. Grafting eggplants onto SH significantly enhanced the total fruit yield as compared to the self-rooted plants exposed to salinity by increasing the average fruit weight. Moreover, salt stress significantly increased the whitening index and oxidation potential of fruits. The plants grafted onto SH or ST accumulated more Na⁺ in their roots than in their fruit or leaves, thus the Na⁺ partitioning between the above-ground and root parts most probably determines the increased salinity tolerance of the grafted ST and SH plants. To conclude, both the SH and ST rootstocks protected the scions against salinity; the scion showed both increased photosynthetic pigment concentration and chlorophyll fluorescence parameters as well as a lower Na⁺ concentration under stress that resulted in a higher fruit yield and quality. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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22 pages, 3467 KiB

Open AccessArticle

Strategies of NaCl Tolerance in Saline–Alkali-Tolerant Green Microalga Monoraphidium dybowskii LB50

by Haijian Yang, Jing Zhang and Hua Li

Plants 2023, 12(19), 3495; https://doi.org/10.3390/plants12193495 - 7 Oct 2023

Cited by 2 | Viewed by 1326

Abstract

Studying how freshwater cells modify metabolism and membrane lipids in response to salt stress is important for understanding how freshwater organisms adapt to salt stress and investigating new osmoregulatory ways. Physiological, biochemical, metabolic, and proteomic analyses were applied in a novel saline–alkali-tolerant microalga [...] Read more.

Studying how freshwater cells modify metabolism and membrane lipids in response to salt stress is important for understanding how freshwater organisms adapt to salt stress and investigating new osmoregulatory ways. Physiological, biochemical, metabolic, and proteomic analyses were applied in a novel saline–alkali-tolerant microalga Monoraphidium dybowskii LB50 under different NaCl concentrations. Cells adopt a variety of strategies to adapt to salt stress, including increasing ion transport and osmolytes, regulating cell cycle and life history, and accumulating triacylglycerol (TAG). A large number of metabolic activities point to TAG accumulation. With increasing NaCl concentration, the C resource for TAG accumulation went from photosynthetically fixed C and a small amount of lipid remodeling to macromolecule degradation and a mass of lipid remodeling, respectively. The energy for TAG accumulation went from linear electron transfer and oxidative phosphate pentose pathway to cyclic electron flow, substrate phosphorylation, oxidation phosphorylation, and FA oxidation. Additionally, digalacturonic acid and amino acids of the N-acetyl group, which usually were the osmotica for marine organisms, were important for M. dybowskii LB50. Freshwater organisms evolved many biological ways to adapt to salt stress. This insight enriches our understanding of the adaptation mechanisms underlying abiotic stress. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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Review

Jump to: Research

12 pages, 821 KiB

Open AccessReview

Sun Protection as a Strategy for Managing Heat Stress in Avocado Trees

by Francisco José Domingues Neto, Débora Cavalcante dos Santos Carneiro, Marcelo de Souza Silva, Marco Antonio Tecchio, Sarita Leonel, Adilson Pimentel Junior, Elizabeth Orika Ono and João Domingos Rodrigues

Plants 2024, 13(20), 2854; https://doi.org/10.3390/plants13202854 - 11 Oct 2024

Viewed by 611

Abstract

The increasing incidence of heat stress due to global climate change poses a significant challenge to avocado (Persea americana) cultivation, particularly in regions with intense solar radiation. This review evaluates sun protection strategies, focusing on the efficacy of different sunscreen products [...] Read more.

The increasing incidence of heat stress due to global climate change poses a significant challenge to avocado (Persea americana) cultivation, particularly in regions with intense solar radiation. This review evaluates sun protection strategies, focusing on the efficacy of different sunscreen products such as kaolin, titanium dioxide, and calcium oxide in mitigating thermal stress in avocado trees. The application of these materials was shown to reduce leaf and fruit surface temperatures, improve photosynthetic efficiency, and enhance fruit quality by preventing sunburn and dehydration. Despite these benefits, challenges remain, including the optimal timing and dosage of application, and the potential residue impacts on fruit marketability. The review emphasizes the need for ongoing research to develop more effective formulations and to integrate these sun protection strategies with other agronomic practices. The role of extension services in educating producers about the proper use of these technologies is also highlighted as crucial for the successful adoption of sun protection measures in avocado farming. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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27 pages, 4224 KiB

Open AccessReview

Quinoa: A Promising Crop for Resolving the Bottleneck of Cultivation in Soils Affected by Multiple Environmental Abiotic Stresses

by Zahra Dehghanian, Mohammad Ahmadabadi, Behnam Asgari Lajayer, Vahideh Gougerdchi, Mohsen Hamedpour-Darabi, Nazila Bagheri, Ritika Sharma, Ramesh R. Vetukuri, Tess Astatkie and Bernard Dell

Plants 2024, 13(15), 2117; https://doi.org/10.3390/plants13152117 - 31 Jul 2024

Viewed by 1760

Abstract

Quinoa (Chenopodium quinoa Willd.) has gained worldwide recognition for its nutritional values, adaptability to diverse environments, and genetic diversity. This review explores the current understanding of quinoa tolerance to environmental stress, focusing on drought, salinity, heat, heavy metals, and UV-B radiation. Although [...] Read more.

Quinoa (Chenopodium quinoa Willd.) has gained worldwide recognition for its nutritional values, adaptability to diverse environments, and genetic diversity. This review explores the current understanding of quinoa tolerance to environmental stress, focusing on drought, salinity, heat, heavy metals, and UV-B radiation. Although drought and salinity have been extensively studied, other stress factors remain underexplored. The ever-increasing incidence of abiotic stress, exacerbated by unpredictable weather patterns and climate change, underscores the importance of understanding quinoa’s responses to these challenges. Global gene banks safeguard quinoa’s genetic diversity, supporting breeding efforts to develop stress-tolerant varieties. Recent advances in genomics and molecular tools offer promising opportunities to improve stress tolerance and increase the yield potential of quinoa. Transcriptomic studies have shed light on the responses of quinoa to drought and salinity, yet further studies are needed to elucidate its resilience to other abiotic stresses. Quinoa’s ability to thrive on poor soils and limited water resources makes it a sustainable option for land restoration and food security enterprises. In conclusion, quinoa is a versatile and robust crop with the potential to address food security challenges under environmental constraints. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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19 pages, 353 KiB

Open AccessReview

Advanced Biotechnological Interventions in Mitigating Drought Stress in Plants

by Özhan Şimşek, Musab A. Isak, Dicle Dönmez, Akife Dalda Şekerci, Tolga İzgü and Yıldız Aka Kaçar

Plants 2024, 13(5), 717; https://doi.org/10.3390/plants13050717 - 4 Mar 2024

Cited by 6 | Viewed by 3805

Abstract

This comprehensive article critically analyzes the advanced biotechnological strategies to mitigate plant drought stress. It encompasses an in-depth exploration of the latest developments in plant genomics, proteomics, and metabolomics, shedding light on the complex molecular mechanisms that plants employ to combat drought stress. [...] Read more.

This comprehensive article critically analyzes the advanced biotechnological strategies to mitigate plant drought stress. It encompasses an in-depth exploration of the latest developments in plant genomics, proteomics, and metabolomics, shedding light on the complex molecular mechanisms that plants employ to combat drought stress. The study also emphasizes the significant advancements in genetic engineering techniques, particularly CRISPR-Cas9 genome editing, which have revolutionized the creation of drought-resistant crop varieties. Furthermore, the article explores microbial biotechnology’s pivotal role, such as plant growth-promoting rhizobacteria (PGPR) and mycorrhizae, in enhancing plant resilience against drought conditions. The integration of these cutting-edge biotechnological interventions with traditional breeding methods is presented as a holistic approach for fortifying crops against drought stress. This integration addresses immediate agricultural needs and contributes significantly to sustainable agriculture, ensuring food security in the face of escalating climate change challenges. Full article

(This article belongs to the Special Issue Abiotic Stress Responses in Plants)

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