Submit to IJMS Review for IJMS Propose a Special Issue

Journal Menu

Journal Browser

A New Era of Sustainability: Plant Biostimulants

Special Issue Editors
Special Issue Information
Keywords
Benefits of Publishing in a Special Issue
Published Papers

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Plant Sciences".

Deadline for manuscript submissions: closed (31 May 2023) | Viewed by 36798

Share This Special Issue

Special Issue Editor

Dr. Giuseppe Mannino

E-Mail Website
Guest Editor

University of Turin;Department of Life Sciences and Systems Biology
Interests: Food Science; Plant Science; HPLC-MS/MS
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In recent years, consumer interest in foods obtained from agricultural practices without the use of agrochemicals has been increasing. This is mainly due to a change in consumer perception, which identifies organic farming as a sustainable technique capable of producing foods that are more natural, safer, and promoters of human health. Then again, there is also evidence of increased human intolerance for many of the agrochemicals commonly used in traditional agriculture and occurring in trace amounts as food contaminants in products from agricultural sources.

In response to this problem, the use of biostimulant formulations is proving to be a sustainable and innovative approach to obtaining foods with high nutritional and nutraceutical quality without recourse to the use of agrochemicals. Biostimulants are products of various origins, both plant and animal, aimed at optimizing plant growth. Consequently, they improve not only production yield but also fruit quality and security. It has been widely demonstrated that the application of these formulations can affect both the primary and secondary metabolism, improve productivity, and influence the nutritional value and nutraceutical profile of foods. They also provide improved plant tolerance to adverse conditions. However, the specific mechanisms remain partially unknown.

This Special Issue of the International Journal of Molecular Sciences aims to present a collection of high-quality original and review articles to inform the scientific community about significant and new information on this topic. In particular, in this Special Issue, the following are welcome:

(a) Original articles evaluating the effect derived from the application of biostimulants in order to increase the resilience of plants to abiotic and biotic stresses. Potential mechanisms of action should be emphasized.

(b) Original articles evaluating the biostimulatory effect of pure compounds or formulations, whether of plant or animal origin, in order to assess potential effects on agronomic yields and food quality.

(c) Articles evaluating the effect of biostimulants on primary and secondary metabolism, and thus on the phytochemical profile, of fruits harvested from treated plants in comparison with untreated plants.

(d) Review articles summarizing the current state of the art.

(e) Metanalyses and bibliometric articles analyzing the trend of the topic in the scientific community at the European or world level.

Dr. Giuseppe Mannino
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

fruit quality
phytochemical profile
plant science
food science
sustainable agriculture
biostimulant
antioxidants
food security
microbial biostimulant
animal-based biostimulant
plant-based biostimulant

Benefits of Publishing in a Special Issue

Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (13 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Editorial

Jump to: Research, Review

3 pages, 193 KiB

Open AccessEditorial

A New Era of Sustainability: Plant Biostimulants

by Giuseppe Mannino

Int. J. Mol. Sci. 2023, 24(22), 16329; https://doi.org/10.3390/ijms242216329 - 15 Nov 2023

Cited by 5 | Viewed by 2550

Abstract

Today, environmental sustainability has become a fundamental concern in nearly every aspect of our daily lives, including the food sector [...] Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

Research

Jump to: Editorial, Review

11 pages, 918 KiB

Open AccessArticle

Effect of Silicon on Micronutrient Content in New Potato Tubers

by Wanda Wadas and Tomasz Kondraciuk

Int. J. Mol. Sci. 2023, 24(13), 10578; https://doi.org/10.3390/ijms241310578 - 24 Jun 2023

Cited by 2 | Viewed by 1491

Abstract

Since silicon can improve nutrient uptake in plants, the effect of foliar silicon (sodium metasilicate) application on micronutrient content in early crop potato tuber was investigated. Silicon was applied at dosages of 23.25 g Si∙ha^–1 or 46.50 g Si∙ha^–1 (0.25 L∙ha^–1 or 0.50 L∙ha^–1 of Optysil) once at the leaf development stage (BBCH 14–16), or at the tuber initiation stage (BBCH 40–1), and twice, at the leaf development and tuber initiation stages. Potatoes were harvested 75 days after planting (the end of June). Foliar-applied silicon reduced the Fe concentration and increased Cu and Mn concentrations in early crop potato tubers under water deficit conditions but did not affect the Zn, B, or Si concentrations. The dosage and time of silicon application slightly affected the Fe and Cu concentration in the tubers. Under drought conditions, the highest Mn content in the tuber was observed when 46.50 g Si∙ha^–1 was applied at the leaf development stage, whereas under periodic water deficits, it was highest with the application of the same silicon dosage at the tuber initiation stage (BBCH 40–41). The Si content in tubers was negatively correlated with the Fe and B content, and positively correlated with the Cu and Mn content. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

21 pages, 2671 KiB

Open AccessArticle

Metabolic Processes and Biological Macromolecules Defined the Positive Effects of Protein-Rich Biostimulants on Sugar Beet Plant Development

by Okanlawon L. Jolayemi, Ali H. Malik, Ramesh R. Vetukuri, Ganapathi V. Saripella, Pruthvi B. Kalyandurg, Tobias Ekblad, Jean W. H. Yong, Marie E. Olsson and Eva Johansson

Int. J. Mol. Sci. 2023, 24(11), 9720; https://doi.org/10.3390/ijms24119720 - 3 Jun 2023

Cited by 3 | Viewed by 3110

Abstract

Protein-based biostimulants (PBBs) have a positive effect on plant development, although the biological background for this effect is not well understood. Here, hydrolyzed wheat gluten (HWG) and potato protein film (PF) in two levels (1 and 2 g/kg soil) and in two different soils (low and high nutrient; LNC and HNC) were used as PBBs. The effect of these PBBs on agronomic traits, sugars, protein, and peptides, as well as metabolic processes, were evaluated on sugar beet in comparison with no treatment (control) and treatment with nutrient solution (NS). The results showed a significant growth enhancement of the plants using HWG and PF across the two soils. Sucrose and total sugar content in the roots were high in NS-treated plants and correlated to root growth in HNC soil. Traits related to protein composition, including nitrogen, peptide, and RuBisCO contents, were enhanced in PBB-treated plants (mostly for HWG and PF at 2 g/kg soil) by 100% and >250% in HNC and LNC, respectively, compared to control. The transcriptomic analysis revealed that genes associated with ribosomes and photosynthesis were upregulated in the leaf samples of plants treated with either HWG or PP compared to the control. Furthermore, genes associated with the biosynthesis of secondary metabolites were largely down-regulated in root samples of HWG or PF-treated plants. Thus, the PBBs enhanced protein-related traits in the plants through a higher transcription rate of genes related to protein- and photosynthesis, which resulted in increased plant growth, especially when added in certain amounts (2 g/kg soil). However, sucrose accumulation in the roots of sugar beet seemed to be related to the easy availability of nitrogen. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

22 pages, 8874 KiB

Open AccessArticle

Cell-Free Supernatant (CFS) from Bacillus subtilis EB2004S and Lactobacillus helveticus EL2006H Cultured at a Range of pH Levels Modulates Potato Plant Growth under Greenhouse Conditions

by Levini A. Msimbira, Judith Naamala, Sowmyalakshmi Subramanian and Donald L. Smith

Int. J. Mol. Sci. 2023, 24(7), 6620; https://doi.org/10.3390/ijms24076620 - 1 Apr 2023

Viewed by 1808

Abstract

Agriculture involving industrial fertilizers is another major human made contributing factor to soil pH variation after natural factors such as soil parent rock, weathering time span, climate, and vegetation. The current study assessed the potential effect of cell-free supernatant (CFS) obtained from Bacillus subtilis EB2004S and Lactobacillus helveticus EL2006H cultured at three pH levels (5, 7, and 8) on potato (var Goldrush) growth enhancement in a greenhouse pot experiment. The results showed that CFSs obtained from B. subtilis EB2004S and L. helveticus EL2006H cultured at pH 5 significantly improved photosynthetic rates, stomatal conductance, root fresh weight, and whole plant fresh weight. interactive effects of pot pH and that of CFSs obtained from pH 5 influenced chlorophyll, plant height, and shoot and whole plant fresh weight. Moreover, treatment 52EB2004S~0.4% initiated early tuberization for potato grown at pH 7 and 8. Potato grown at pH 5, which received a 72EB2004S~0.4% CFS treatment, had greater whole plant fresh and dry weight than that treated with L. helveticus EL2006H CFS and a positive control. Taken together, the findings of this study are unique in that it probed the effect of CFS produced under differing pH conditions which revealed a new possibility to mitigate stresses in plants. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

18 pages, 2885 KiB

Open AccessArticle

Transcriptomic Analysis of Heat Stress Response in Brassica rapa L. ssp. pekinensis with Improved Thermotolerance through Exogenous Glycine Betaine

by Jin Quan, Xinyuan Li, Zewei Li, Meifang Wu, Biao Zhu, Seung-Beom Hong, Jiang Shi, Zhujun Zhu, Liai Xu and Yunxiang Zang

Int. J. Mol. Sci. 2023, 24(7), 6429; https://doi.org/10.3390/ijms24076429 - 29 Mar 2023

Cited by 5 | Viewed by 2655

Abstract

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is sensitive to high temperature, which will cause the B. rapa to remain in a semi-dormancy state. Foliar spray of GB prior to heat stress was proven to enhance B. rapa thermotolerance. In order to understand the molecular mechanisms of GB-primed resistance or adaptation towards heat stress, we investigated the transcriptomes of GB-primed and non-primed heat-sensitive B. rapa ‘Beijing No. 3’ variety by RNA-Seq analysis. A total of 582 differentially expressed genes (DEGs) were identified from GB-primed plants exposed to heat stress relative to non-primed plants under heat stress and were assigned to 350 gene ontology (GO) pathways and 69 KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways. The analysis of the KEGG enrichment pathways revealed that the most abundantly up-regulated pathways were protein processing in endoplasmic reticulum (14 genes), followed by plant hormone signal transduction (12 genes), ribosome (8 genes), MAPK signaling pathway (8 genes), homologous recombination (7 genes), nucleotide excision repair metabolism (5 genes), glutathione metabolism (4 genes), and ascorbate and aldarate metabolism (4 genes). The most abundantly down-regulated pathways were plant-pathogen interaction (14 genes), followed by phenylpropanoid biosynthesis (7 genes); arginine and proline metabolism (6 genes); cutin, suberine, and wax biosynthesis (4 genes); and tryptophan metabolism (4 genes). Several calcium sensing/transducing proteins, as well as transcription factors associated with abscisic acid (ABA), salicylic acid (SA), auxin, and cytokinin hormones were either up- or down-regulated in GB-primed B. rapa plants under heat stress. In particular, expression of the genes for antioxidant defense, heat shock response, and DNA damage repair systems were highly increased by GB priming. On the other hand, many of the genes involved in the calcium sensors and cell surface receptors involved in plant innate immunity and the biosynthesis of secondary metabolites were down-regulated in the absence of pathogen elicitors in GB-primed B. rapa seedlings. Overall GB priming activated ABA and SA signaling pathways but deactivated auxin and cytokinin signaling pathways while suppressing the innate immunity in B. rapa seedlings exposed to heat stress. The present study provides a preliminary understanding of the thermotolerance mechanisms in GB-primed plants and is of great importance in developing thermotolerant B. rapa cultivars by using the identified DEGs through genetic modification. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

25 pages, 3961 KiB

Open AccessArticle

Changes in the Phytochemical Profile and Antioxidant Properties of Prunus persica Fruits after the Application of a Commercial Biostimulant Based on Seaweed and Yeast Extract

by Giuseppe Mannino, Maddalena Ricciardi, Noemi Gatti, Graziella Serio, Ivano Vigliante, Valeria Contartese, Carla Gentile and Cinzia M. Bertea

Int. J. Mol. Sci. 2022, 23(24), 15911; https://doi.org/10.3390/ijms232415911 - 14 Dec 2022

Cited by 7 | Viewed by 2542

Abstract

Plant biostimulants are formulations that are experiencing great success from the perspective of sustainable agriculture. In this work, we evaluated the effect derived from the application of a biostimulant based on algae and yeast extracts (Expando^®) on the agronomic yield and nutraceutical profile of two different cultivars (“Sugar Time” and “West Rose”) of Prunus persica (peach). Although, at the agronomic level, significant effects on production yields were not recorded, the biostimulant was able to reduce the ripening time, increase the fruit size, and make the number of harvestable fruits homogeneous. From a nutraceutical point of view, our determinations via spectrophotometric (UV/Vis) and chromatographic (HPLC-DAD-MS/MS) analysis showed that the biostimulant was able to boost the content of bioactive compounds in both the pulp (5.0 L/ha: +17%; 4.0 L/ha: +12%; 2.5 L/ha: +11%) and skin (4.0 L/ha: +38%; 2.5 L/ha: +15%). These changes seem to follow a dose-dependent effect, also producing attractive effects on the antioxidant properties of the fruits harvested from the treated trees. In conclusion, the biostimulant investigated in this work proved to be able to produce more marketable fruit in a shorter time, both from a pomological and a functional point of view. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

19 pages, 2527 KiB

Open AccessArticle

Secretome Analysis of the Plant Biostimulant Bacteria Strains Bacillus subtilis (EB2004S) and Lactobacillus helveticus (EL2006H) in Response to pH Changes

by Levini A. Msimbira, Sowmyalakshmi Subramanian, Judith Naamala, Mohammed Antar and Donald L. Smith

Int. J. Mol. Sci. 2022, 23(23), 15144; https://doi.org/10.3390/ijms232315144 - 2 Dec 2022

Cited by 5 | Viewed by 2506

Abstract

It is well-known that there is a high frequency of plant-growth-promoting strains in Bacillus subtilis and that these can be effective under both stressful and stress-free conditions. There are very few studies of this activity in the case of Lactobacillus helveticus. In this study, the effects of pH on the secretome (proteins) in the cell-free supernatants of two bacterial strains were evaluated. The bacteria were cultured at pH 5, 7 and 8, and their secretome profiles were analyzed, with pH 7 (optimal growth pH) considered as the “control”. The results showed that acidity (lower pH 5) diminishes the detectable production of most of the secretome proteins, whereas alkalinity (higher pH 8) increases the detectable protein production. At pH 5, five (5) new proteins were produced by L. helveticus, including class A sortase, fucose-binding lectin II, MucBP-domain-containing protein, SLAP-domain-containing protein and hypothetical protein LHEJCM1006_11110, whereas for B. subtilis, four (4) types of proteins were uniquely produced (p ≤ 0.05), including helicase-exonuclease AddAB subunit AddB, 5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase, a cluster of ABC-F family ATP-binding-cassette-domain-containing proteins and a cluster of excinuclease ABC (subunit B). At pH 8, Bacillus subtilis produced 56 unique proteins. Many of the detected proteins were involved in metabolic processes, whereas the others had unknown functions. The unique and new proteins with known and unknown functions suggest potential the acclimatization of the microbes to pH stress. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

23 pages, 4106 KiB

Open AccessArticle

Enhanced Resistance to Sclerotinia sclerotiorum in Brassica rapa by Activating Host Immunity through Exogenous Verticillium dahliae Aspf2-like Protein (VDAL) Treatment

by Shufang Jiang, Weiwei Zheng, Zewei Li, Jingru Tan, Meifang Wu, Xinyuan Li, Seung-Beom Hong, Jianyu Deng, Zhujun Zhu and Yunxiang Zang

Int. J. Mol. Sci. 2022, 23(22), 13958; https://doi.org/10.3390/ijms232213958 - 12 Nov 2022

Cited by 8 | Viewed by 2479

Abstract

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the most destructive diseases in Brassica rapa. Verticillium dahliae Aspf2-like protein (VDAL) is a secretory protein of V. dahliae which has been shown to enhance the resistance against fungal infections in several plants. Nonetheless, the molecular mechanisms of VDAL-primed disease resistance are still poorly understood. In this study, we performed physiological, biochemical, and transcriptomic analyses of Brassica rapa in order to understand how VDAL confers resistance to S. sclerotiorumn infections in plants. The results showed that foliar application of VDAL significantly reduced the plaque area on leaves inoculated with S. sclerotiorum. It also enhanced antioxidant capacity by increasing activities of superoxide dismutase (SOD), peroxidase (POD), peroxidase (APX), glutathione reductase (GR), protoporphyrinogen oxidase (PPO), and defense-related enzymes β-1,3-glucanase and chitinase during the infection periods. This occurred in parallel with significantly reduced relative conductivity at different periods and lower malondialdehyde (MDA) content as compared to sole S. sclerotiorum inoculation. Transcriptomic analysis showed a total of 146 (81 up-regulated and 65 down-regulated) differentially expressed genes (DEGs) in VDAL-treated leaves compared to the control. The most enriched three Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were the mitogen–activated protein kinase (MAPK) signaling pathway, plant hormone signal transduction, and plant-pathogen interaction, all of which were associated with plant immunity. DEGs associated with MAPK and hormone signal transduction pathways were ethylene response sensor ERS2, EIN3 (Ethylene Insensitive3)-binding F-box protein 2 (EBF2), ethylene-responsive transcription factor ERF94, MAPK 9 (MKK9), protein phosphatase 2C (PP2C37), auxin-responsive proteins (AUX/IAA1 and 19), serine/threonine-protein kinase CTR1, and abscisic acid receptors (PLY 4 and 5). Among the DEGs linked with the plant–pathogen interaction pathway were calmodulin-like proteins (CML5, 24, 27), PTI1-like tyrosine protein kinase 3 (Pti13) and transcription factor MYB30, all of which are known to play key roles in pathogen-associated molecular pattern (PAMP)-triggered immunity and effector-triggered immunity (ETI) for hypersensitive response (HR), cell wall reinforcement, and stomatal closure in plants. Overall, VDLA treatment triggered repression of the auxin and ABA signaling pathways and de-repression of the ethylene signaling pathways in young B. rapa seedlings to increase plant innate immunity. Our results showed that VDAL holds great potential to enhance fungal disease resistance in B. rapa crop. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

16 pages, 3571 KiB

Open AccessArticle

Effects of Exogenous L-Asparagine on Poplar Biomass Partitioning and Root Morphology

by Mei Han, Shizhen Wang, Liangdan Wu, Junhu Feng, Yujia Si, Xiaoning Liu and Tao Su

Int. J. Mol. Sci. 2022, 23(21), 13126; https://doi.org/10.3390/ijms232113126 - 28 Oct 2022

Cited by 3 | Viewed by 2134

Abstract

L-Asparagine (Asn) has been regarded as one of the most economical molecules for nitrogen (N) storage and transport in plants due to its relatively high N-to-carbon (C) ratio (2:4) and stability. Although its internal function has been addressed, the biological role of exogenous Asn in plants remains elusive. In this study, different concentrations (0.5, 1, 2, or 5 mM) of Asn were added to the N-deficient hydroponic solution for poplar ‘Nanlin895’. Morphometric analyses showed that poplar height, biomass, and photosynthesis activities were significantly promoted by Asn treatment compared with the N-free control. Moreover, the amino acid content, total N and C content, and nitrate and ammonia content were dramatically altered by Asn treatment. Moreover, exogenous Asn elicited root growth inhibition, accompanied by complex changes in the transcriptional pattern of genes and activities of enzymes associated with N and C metabolism. Combined with the plant phenotype and the physiological and biochemical indexes, our data suggest that poplar is competent to take up and utilize exogenous Asn dose-dependently. It provides valuable information and insight on how different forms of N and concentrations of Asn influence poplar root and shoot growth and function, and roles of Asn engaged in protein homeostasis regulation. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

20 pages, 5260 KiB

Open AccessArticle

Transcriptional and Metabolic Characterization of Feeding Ramie Growth Enhanced by a Combined Application of Gibberellin and Ethrel

by Hongdong Jie, Yushen Ma, De-Yu Xie and Yucheng Jie

Int. J. Mol. Sci. 2022, 23(19), 12025; https://doi.org/10.3390/ijms231912025 - 10 Oct 2022

Cited by 6 | Viewed by 1796

Abstract

Feeding ramie cultivars (Boehmaria nivea L.) are an important feedstock for livestock. Increasing their biomass and improving their nutritional values are essential for animal feeding. Gibberellin (GA₃) and ethylene (ETH) are two plant hormones that regulate the growth, development, and metabolism of plants. Herein, we report effects of the GA₃ and ETH application on the growth and plant metabolism of feeding ramie in the field. A combination of GA₃ and ETH was designed to spray new plants. The two hormones enhanced the growth of plants to produce more biomass. Meanwhile, the two hormones reduced the contents of lignin in leaves and stems, while increased the content of flavonoids in leaves. To understand the potential mechanisms behind these results, we used RNA-seq-based transcriptomics and UPLC-MS/MS-based metabolomics to characterize gene expression and metabolite profiles associated with the treatment of GA₃ and ETH. 1562 and 2364 differentially expressed genes (DEGs) were obtained from leaves and stems (treated versus control), respectively. Meanwhile, 99 and 88 differentially accumulated metabolites (DAMs) were annotated from treated versus control leaves and treated versus control stems, respectively. Data mining revealed that both DEGs and DAMs were associated with multiple plant metabolisms, especially plant secondary metabolism. A specific focus on the plant phenylpropanoid pathway identified candidates of DEGs and DEMs that were associated with lignin and flavonoid biosynthesis. Shikimate hydroxycinnamoyl transferase (HCT) is a key enzyme that is involved in the lignin biosynthesis. The gene encoding B. nivea HCT was downregulated in the treated leaves and stems. In addition, genes encoding 4-coumaryl CoA ligase (4CL) and trans-cinnamate 4-monooxygenase (CYP73A), two lignin pathway enzymes, were downregulated in the treated stems. Meanwhile, the reduction in lignin in the treated leaves led to an increase in cinnamic acid and p-coumaryl CoA, two shared substrates of flavonoids that are enhanced in contents. Taken together, these findings indicated that an appropriate combination of GA₃ and ETH is an effective strategy to enhance plant growth via altering gene expression and plant secondary metabolism for biomass-enhanced and value-improved feeding ramie. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

19 pages, 3289 KiB

Open AccessArticle

Glutamic Acid and Poly-γ-glutamic Acid Enhanced the Heat Resistance of Chinese Cabbage (Brassica rapa L. ssp. pekinensis) by Improving Carotenoid Biosynthesis, Photosynthesis, and ROS Signaling

by Jin Quan, Weiwei Zheng, Jingru Tan, Zewei Li, Meifang Wu, Seung-Beom Hong, Yanting Zhao, Zhujun Zhu and Yunxiang Zang

Int. J. Mol. Sci. 2022, 23(19), 11671; https://doi.org/10.3390/ijms231911671 - 1 Oct 2022

Cited by 13 | Viewed by 2883

Abstract

Heat stress is one of the most common agrometeorological risks in crop production in the middle and lower reaches of the Yangtze River in China. This study aimed to investigate whether glutamic acid (Glu) or poly-γ-glutamic acid (γ-PGA) biostimulants can improve the thermotolerance of a cool-season Chinese cabbage (Brassica rapa L. ssp. pekinensis) crop. Priming with Glu (2.0 mM) or γ-PGA (20 mg·L⁻¹) was conducted at the third leaf stage by applying as daily foliar sprays for 5 days before 5 days of heat stress (45 °C in 16-h light/35 °C in 8-h dark). Coupled with morpho-physiological and biochemical analyses, transcriptomes of Glu or γ-PGA-primed Chinese cabbage under heat stress were examined by RNA-seq analysis. The results showed that the thermotolerance conferred by Glu and γ-PGA priming was associated with the increased parameters of vegetative growth, gas exchange, and chlorophyll fluorescence. Compared with the control, the dry weights of plants treated with Glu and γ-PGA increased by 51.52% and 39.39%, respectively. Glu and γ-PGA application also significantly increased the contents of total chlorophyll by 42.21% and 23.12%, and carotenoid by 32.00% and 24.00%, respectively. In addition, Glu- and γ-PGA-primed plants markedly inhibited the levels of malondialdehyde, electrolyte leakage, and super-oxide anion radical, which was accompanied by enhanced activity levels of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD). Enrichment analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) categories within the differentially expressed genes (DEGs) functional clusters of RNA-seq data indicated that the expression levels of the genes for DNA replication, DNA repair system, linoleic acid metabolism, cysteine and methionine metabolism, glutathione metabolism, purine and pyrimidine metabolism, carotenoid biosynthesis, and plant–pathogen interaction were commonly up-regulated by both Glu and γ-PGA priming. Glu treatment enhanced the expression levels of the genes involved in aliphatic glucosinolate and 2-oxocarboxylic acid, while γ-PGA treatment activated carotenoid cleavage reaction to synthesize abscisic acid. Taken together, both Glu and γ-PGA have great potential for the preadaptation of Chinese cabbage seedlings to heat stress, with Glu being more effective than γ-PGA. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

Review

Jump to: Editorial, Research

17 pages, 1179 KiB

Open AccessReview

Biostimulant Properties of Protein Hydrolysates: Recent Advances and Future Challenges

by Marthe Malécange, Renaud Sergheraert, Béatrice Teulat, Emmanuelle Mounier, Jérémy Lothier and Soulaiman Sakr

Int. J. Mol. Sci. 2023, 24(11), 9714; https://doi.org/10.3390/ijms24119714 - 3 Jun 2023

Cited by 24 | Viewed by 6159

Abstract

Over the past decade, plant biostimulants have been increasingly used in agriculture as environment-friendly tools that improve the sustainability and resilience of crop production systems under environmental stresses. Protein hydrolysates (PHs) are a main category of biostimulants produced by chemical or enzymatic hydrolysis of proteins from animal or plant sources. Mostly composed of amino acids and peptides, PHs have a beneficial effect on multiple physiological processes, including photosynthetic activity, nutrient assimilation and translocation, and also quality parameters. They also seem to have hormone-like activities. Moreover, PHs enhance tolerance to abiotic stresses, notably through the stimulation of protective processes such as cell antioxidant activity and osmotic adjustment. Knowledge on their mode of action, however, is still piecemeal. The aims of this review are as follows: (i) Giving a comprehensive overview of current findings about the hypothetical mechanisms of action of PHs; (ii) Emphasizing the knowledge gaps that deserve to be urgently addressed with a view to efficiently improve the benefits of biostimulants for different plant crops in the context of climate change. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Figure 1

13 pages, 1088 KiB

Open AccessReview

Role of Melatonin and Nitrogen Metabolism in Plants: Implications under Nitrogen-Excess or Nitrogen-Low

by Marino B. Arnao, Josefa Hernández-Ruiz and Antonio Cano

Int. J. Mol. Sci. 2022, 23(23), 15217; https://doi.org/10.3390/ijms232315217 - 2 Dec 2022

Cited by 11 | Viewed by 3417

Abstract

Melatonin is a new plant hormone involved in multiple physiological functions in plants such as germination, photosynthesis, plant growth, flowering, fruiting, and senescence, among others. Its protective role in different stress situations, both biotic and abiotic, has been widely demonstrated. Melatonin regulates several routes in primary and secondary plant metabolism through the up/down-regulation of many enzyme/factor genes. Many of the steps of nitrogen metabolism in plants are also regulated by melatonin and are presented in this review. In addition, the ability of melatonin to enhance nitrogen uptake under nitrogen-excess or nitrogen-low conditions is analyzed. A model that summarizes the distribution of nitrogen compounds, and the osmoregulation and redox network responses mediated by melatonin, are presented. The possibilities of using melatonin in crops for more efficient uptake, the assimilation and metabolization of nitrogen from soil, and the implications for Nitrogen Use Efficiency strategies to improve crop yield are also discussed. Full article

(This article belongs to the Special Issue A New Era of Sustainability: Plant Biostimulants)

► Show Figures

Journal Menu

Journal Browser

A New Era of Sustainability: Plant Biostimulants

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (13 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI