WRKY transcription factors and OBERON histone-binding proteins form complexes to balance plant growth and stress tolerance.

WRKY transcription factors in plants are known to be able to mediate either transcriptional activation or repression, but the mechanism regulating their transcriptional activity is largely unclear. We found that group IId WRKY transcription factors interact with OBERON (OBE) proteins, forming redundant WRKY-OBE complexes in Arabidopsis thaliana. The coiled-coil domain of WRKY transcription factors binds to OBE proteins and is responsible for target gene selection and transcriptional repression. The PHD finger of OBE proteins binds to both histones and WRKY transcription factors. WRKY-OBE complexes repress the transcription of numerous stress-responsive genes and are required for maintaining normal plant growth. Several WRKY and OBE mutants show reduced plant size and increased drought tolerance, accompanied by increased expression of stress-responsive genes. Moreover, expression levels of most of these WRKY and OBE genes are reduced in response to drought stress, revealing a previously uncharacterized regulatory mechanism of the drought stress response. These results suggest that WRKY-OBE complexes repress transcription of stress-responsive genes, and thereby balance plant growth and stress tolerance.

Loss of the ceramide synthase HYL-2 from Caenorhabditis elegans impairs stress responses and alters sphingolipid composition.

Sphingolipids, essential membrane components and signaling molecules in cells, have ceramides at the core of their metabolic pathways. Initially termed as "longevity assurance genes", the encoding genes of ceramide synthases are closely associated with individual aging and stress responses, although the mechanisms remain unclear. This study aims to explore the alterations and underlying mechanisms of three ceramide synthases, HYL-1, HYL-2, and LAGR-1, in the aging and stress responses of Caenorhabditis elegans. Our results showed the knockdown of HYL-1 extends the lifespan and enhance stress resistance in worms, whereas the loss of HYL-2 function significantly impairs tolerances to heat, oxidation, and ultraviolet stress. Stress intolerance induced by HYL-2 deficiency may result from intracellular mitochondrial dysfunction, accumulation of reactive oxygen species, and abnormal nuclear translocation of DAF-16 under stress conditions. Loss of HYL-2 led to a significant reduction of predominant ceramides (d17:1/C20∼C23) as well as corresponding complex sphingolipids. Furthermore, the N-acyl chain length composition of sphingolipids underwent dramatic modifications, characterized by a decrease in C22 sphingolipids and an increase in C24 sphingolipids. Extra d18:1-ceramides resulted in diminished stress resilience in wild-type worms, while supplementation of d18:1/C16 ceramide to HYL-2-deficient worms marginally improved stress tolerance to heat and oxidation. These findings indicate the importance of appropriate ceramide content and composition in maintaining subcellular homeostasis and nuclear-cytoplasmic signal transduction during healthy aging and stress responses.

A Solanum lycopersicum polyamine oxidase contributes to the control of plant growth, xylem differentiation, and drought stress tolerance.

Polyamines are involved in several plant physiological processes. In Arabidopsis thaliana, five FAD-dependent polyamine oxidases (AtPAO1 to AtPAO5) contribute to polyamine homeostasis. AtPAO5 catalyzes the back-conversion of thermospermine (T-Spm) to spermidine and plays a role in plant development, xylem differentiation, and abiotic stress tolerance. In the present study, to verify whether T-Spm metabolism can be exploited as a new route to improve stress tolerance in crops and to investigate the underlying mechanisms, tomato (Solanum lycopersicum) AtPAO5 homologs were identified (SlPAO2, SlPAO3, and SlPAO4) and CRISPR/Cas9-mediated loss-of-function slpao3 mutants were obtained. Morphological, molecular, and physiological analyses showed that slpao3 mutants display increased T-Spm levels and exhibit changes in growth parameters, number and size of xylem elements, and expression levels of auxin- and gibberellin-related genes compared to wild-type plants. The slpao3 mutants are also characterized by improved tolerance to drought stress, which can be attributed to a diminished xylem hydraulic conductivity that limits water loss, as well as to a reduced vulnerability to embolism. Altogether, this study evidences conservation, though with some significant variations, of the T-Spm-mediated regulatory mechanisms controlling plant growth and differentiation across different plant species and highlights the T-Spm role in improving stress tolerance while not constraining growth.

Upregulation of fibronectin and its integrin receptors - an adaptation to isolation stress that facilitates tumor initiation.

Tumor initiation at either primary or metastatic sites is an inefficient process in which tumor cells must fulfill a series of conditions. One critical condition involves the ability of individual tumor-initiating cells to overcome 'isolation stress', enabling them to survive within harsh isolating microenvironments that can feature nutrient stress, hypoxia, oxidative stress and the absence of a proper extracellular matrix (ECM). In response to isolation stress, tumor cells can exploit various adaptive strategies to develop stress tolerance and gain stemness features. In this Opinion, we discuss how strategies such as the induction of certain cell surface receptors and deposition of ECM proteins enable tumor cells to endure isolation stress, thereby gaining tumor-initiating potential. As examples, we highlight recent findings from our group demonstrating how exposure of tumor cells to isolation stress upregulates the G-protein-coupled receptor lysophosphatidic acid receptor 4 (LPAR4), its downstream target fibronectin and two fibronectin-binding integrins, α5ß1 and αvß3. These responses create a fibronectin-rich niche for tumor cells, ultimately driving stress tolerance, cancer stemness and tumor initiation. We suggest that approaches to prevent cancer cells from adapting to stress by suppressing LPAR4 induction, blocking its downstream signaling or disrupting fibronectin-integrin interactions hold promise as potential strategies for cancer treatment.

Differential Protein Expression in Set5p-Mediated Acetic Acid Stress Response and Novel Targets for Engineering Yeast Stress Tolerance.

Acetic acid is a prevalent inhibitor in lignocellulosic hydrolysate, which represses microbial growth and bioproduction. Histone modification and chromatin remodeling have been revealed to be critical for regulating eukaryotic metabolism. However, related studies in chronic acetic acid stress responses remain unclear. Our previous studies revealed that overexpression of the histone H4 methyltransferase Set5p enhanced acetic acid stress tolerance of the budding yeast Saccharomyces cerevisiae. In this study, we examined the role of Set5p in acetic acid stress by analyzing global protein expression. Significant activation of intracellular protein expression under the stress was discovered, and the functions of the differential proteins were mainly involved in chromatin modification, signal transduction, and carbohydrate metabolism. Notably, a substantial increase of Set5p expression was observed in response to acetic acid stress. Functional studies demonstrated that the restriction of the telomere capping protein Rtc3p, as well as Ies3p and Taf14p, which are related to chromatin regulation, was critical for yeast stress response. This study enriches the understanding of the epigenetic regulatory mechanisms underlying yeast stress response mediated by histone-modifying enzymes. The results also benefit the development of robust yeast strains for lignocellulosic bioconversion.

Mdm-miR160-MdARF17-MdWRKY33 module mediates freezing tolerance in apple.

Apple (Malus domestica) trees are vulnerable to freezing temperatures. Cold resistance in woody perennial plants can be improved through biotechnological approaches. However, genetic engineering requires a thorough understanding of the molecular mechanisms of the tree's response to cold. In this study, we demonstrated that the Mdm-miR160-MdARF17-MdWRKY33 module is crucial for apple freezing tolerance. Mdm-miR160 plays a negative role in apple freezing tolerance, whereas MdARF17, one of the targets of Mdm-miR160, is a positive regulator of apple freezing tolerance. RNA sequencing analysis revealed that in apple, MdARF17 mediates the cold response by influencing the expression of cold-responsive genes. EMSA and ChIP-qPCR assays demonstrated that MdARF17 can bind to the promoter of MdWRKY33 and promotes its expression. Overexpression of MdWRKY33 enhanced the cold tolerance of the apple calli. In addition, we found that the Mdm-miR160-MdARF17-MdWRKY33 module regulates cold tolerance in apple by regulating reactive oxygen species (ROS) scavenging, as revealed by (i) increased H2 O2 levels and decreased peroxidase (POD) and catalase (CAT) activities in Mdm-miR160e OE plants and MdARF17 RNAi plants and (ii) decreased H2 O2 levels and increased POD and CAT activities in MdmARF17 OE plants and MdWRKY33 OE calli. Taken together, our study uncovered the molecular roles of the Mdm-miR160-MdARF17-MdWRKY33 module in freezing tolerance in apple, thus providing support for breeding of cold-tolerant apple cultivars.

Metabolic priming in G6PDH isoenzyme-replaced tobacco lines improves stress tolerance and seed yields via altering assimilate partitioning.

We investigated the basis for better performance of transgenic Nicotiana tabacum plants with G6PDH-isoenzyme replacement in the cytosol (Xanthi::cP2::cytRNAi, Scharte et al., 2009). After six generations of selfing, infiltration of Phytophthora nicotianae zoospores into source leaves confirmed that defence responses (ROS, callose) are accelerated, showing as fast cell death of the infected tissue. Yet, stress-related hormone profiles resembled susceptible Xanthi and not resistant cultivar SNN, hinting at mainly metabolic adjustments in the transgenic lines. Leaves of non-stressed plants contained twofold elevated fructose-2,6-bisphosphate (F2,6P2 ) levels, leading to partial sugar retention (soluble sugars, starch) and elevated hexose-to-sucrose ratios, but also more lipids. Above-ground biomass lay in between susceptible Xanthi and resistant SNN, with photo-assimilates preferentially allocated to inflorescences. Seeds were heavier with higher lipid-to-carbohydrate ratios, resulting in increased harvest yields - also under water limitation. Abiotic stress tolerance (salt, drought) was improved during germination, and in floated leaf disks of non-stressed plants. In leaves of salt-watered plants, proline accumulated to higher levels during illumination, concomitant with efficient NADP(H) use and recycling. Non-stressed plants showed enhanced PSII-induction kinetics (upon dark-light transition) with little differences at the stationary phase. Leaf exudates contained 10% less sucrose, similar amino acids, but more fatty acids - especially in the light. Export of specific fatty acids via the phloem may contribute to both, earlier flowering and higher seed yields of the Xanthi-cP2 lines. Apparently, metabolic priming by F2,6P2 -combined with sustained NADP(H) turnover-bypasses the genetically fixed growth-defence trade-off, rendering tobacco plants more stress-resilient and productive.

1-Butanol treatment enhances drought stress tolerance in Arabidopsis thaliana.

Abiotic stress is a major factor affecting crop productivity. Chemical priming is a promising strategy to enhance tolerance to abiotic stress. In this study, we evaluated the use of 1-butanol as an effectual strategy to enhance drought stress tolerance in Arabidopsis thaliana. We first demonstrated that, among isopropanol, methanol, 1-butanol, and 2-butanol, pretreatment with 1-butanol was the most effective for enhancing drought tolerance. We tested the plants with a range of 1-butanol concentrations (0, 10, 20, 30, 40, and 50 mM) and further determined that 20 mM was the optimal concentration of 1-butanol that enhanced drought tolerance without compromising plant growth. Physiological tests showed that the enhancement of drought tolerance by 1-butanol pretreatment was associated with its stimulation of stomatal closure and improvement of leaf water retention. RNA-sequencing analysis revealed the differentially expressed genes (DEGs) between water- and 1-butanol-pretreated plants. The DEGs included genes involved in oxidative stress response processes. The DEGs identified here partially overlapped with those of ethanol-treated plants. Taken together, the results show that 1-butanol is a novel chemical priming agent that effectively enhances drought stress tolerance in Arabidopsis plants, and provide insights into the molecular mechanisms of alcohol-mediated abiotic stress tolerance.

Volatile Compounds Emitted by Plant Growth-Promoting Fungus Tolypocladium inflatum GT22 Alleviate Copper and Pathogen Stress.

Previous studies on the intricate interactions between plants and microorganisms have revealed that fungal volatile compounds (VCs) can affect plant growth and development. However, the precise mechanisms underlying these actions remain to be delineated. In this study, we discovered that VCs from the soilborne fungus Tolypocladium inflatum GT22 enhance the growth of Arabidopsis. Remarkably, priming Arabidopsis with GT22 VCs caused the plant to display an enhanced immune response and mitigated the detrimental effects of both pathogenic infections and copper stress. Transcriptomic analyses of Arabidopsis seedlings treated with GT22 VCs for 3, 24 and 48 h revealed that 90, 83 and 137 genes were differentially expressed, respectively. The responsive genes are known to be involved in growth, hormone regulation, defense mechanisms and signaling pathways. Furthermore, we observed the induction of genes related to innate immunity, hypoxia, salicylic acid biosynthesis and camalexin biosynthesis by GT22 VCs. Among the VCs emitted by GT22, exposure of Arabidopsis seedlings to limonene promoted plant growth and attenuated copper stress. Thus, limonene appears to be a key mediator of the interaction between GT22 and plants. Overall, our findings provide evidence that fungal VCs can promote plant growth and enhance both biotic and abiotic tolerance. As such, our study suggests that exposure of seedlings to T. inflatum GT22 VCs may be a means of improving crop productivity. This study describes a beneficial interaction between T. inflatun GT22 and Arabidopsis. Our investigation of microorganism function in terms of VC activities allowed us to overcome the limitations of traditional microbial application methods. The importance of this study lies in the discovery of T. inflatun GT22 as a beneficial microorganism. This soilborne fungus emits VCs with plant growth-promoting effects and the ability to alleviate both copper and pathogenic stress. Furthermore, our study offers a valuable approach to tracking the activities of fungal VC components via transcriptomic analysis and sheds light on the mechanisms through which VCs promote plant growth and induce resistance. This research significantly advances our knowledge of VC applications and provides an example for further investigations within this field.

Genome-wide analysis of the switchgrass YABBY family and functional characterization of PvYABBY14 in response to ABA and GA stress in Arabidopsis.

BACKGROUND: The small YABBY plant-specific transcription factor has a prominent role in regulating plant growth progress and responding to abiotic stress. RESULTS: Here, a total of 16 PvYABBYs from switchgrass (Panicum virgatum L.) were identified and classified into four distinct subgroups. Proteins within the same subgroup exhibited similar conserved motifs and gene structures. Synteny analyses indicated that segmental duplication contributed to the expansion of the YABBY gene family in switchgrass and that complex duplication events occurred in rice, maize, soybean, and sorghum. Promoter regions of PvYABBY genes contained numerous cis-elements related to stress responsiveness and plant hormones. Expression profile analysis indicated higher expression levels of many PvYABBY genes during inflorescence development and seed maturation, with lower expression levels during root growth. Real-time quantitative PCR analysis demonstrated the sensitivity of multiple YABBY genes to PEG, NaCl, ABA, and GA treatments. The overexpression of PvYABBY14 in Arabidopsis resulted in increased root length after treatment with GA and ABA compared to wild-type plants. CONCLUSIONS: Taken together, our study provides the first genome-wide overview of the YABBY transcription factor family, laying the groundwork for understanding the molecular basis and regulatory mechanisms of PvYABBY14 in response to ABA and GA responses in switchgrass.

TaWRKY31, a novel WRKY transcription factor in wheat, participates in regulation of plant drought stress tolerance.

BACKGROUND: Wheat, a crucial food crop in China, is highly vulnerable to drought stress throughout its growth and development. WRKY transcription factors (TFs), being one of the largest families of TFs, play a vital role in responding to various abiotic stresses in plants. RESULTS: Here, we cloned and characterized the TF TaWRKY31 isolated from wheat. This TF, belonging to the WRKY II family, contains a WRKYGQK amino acid sequence and a C2H2-type zinc finger structure. TaWRKY31 exhibits tissue-specific expression and demonstrates responsiveness to abiotic stresses in wheat. TaWRKY31 protein is localized in the nucleus and can function as a TF with transcription activating activity at the N-terminus. Results showed that the wheat plants with silenced strains (BSMV:TaWRKY31-1as and BSMV:TaWRKY31-2as) exhibited poor growth status and low relative water content when subjected to drought treatment. Moreover, the levels of O2·-, H2O2, and malondialdehyde (MDA) in the BSMV:TaWRKY31-induced wheat plants increased, while the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) decreased. Compared to control plants, BSMV:TaWRKY31-induced wheat plants exhibited lower expression levels of TaSOD (Fe), TaPOD, TaCAT, TaDREB1, TaP5CS, TaNCED1, TaSnRK2, TaPP2C, and TaPYL5.Under stress or drought treatment conditions, the overexpression of TaWRKY31 in Arabidopsis resulted in decreased levels of H2O2 and MDA, as well as reduced stomatal opening and water loss. Furthermore, an increase in resistance oxidase activity, germination rate, and root length in the TaWRKY31 transgenic Arabidopsis was observed. Lastly, overexpression of TaWRKY31 in Arabidopsis resulted in higher the expression levels of AtNCED3, AtABA2, AtSnRK2.2, AtABI1, AtABF3, AtP5CS1, AtSOD (Cu/Zn), AtPOD, AtCAT, AtRD29A, AtRD29B, and AtDREB2A than in control plants. CONCLUSIONS: Our findings indicate that TaWRKY31 enhances drought resistance in plants by promoting the scavenging of reactive oxygen species, reducing stomatal opening, and increasing the expression levels of stress-related genes.

Genome-wide association study for seedling heat tolerance under two temperature conditions in bread wheat (Triticum aestivum L.).

BACKGROUND: As the greenhouse effect intensifies, global temperatures are steadily increasing, posing a challenge to bread wheat (Triticum aestivum L.) production. It is imperative to comprehend the mechanism of high temperature tolerance in wheat and implement breeding programs to identify and develop heat-tolerant wheat germplasm and cultivars. RESULTS: To identify quantitative trait loci (QTL) related to heat stress tolerance (HST) at seedling stage in wheat, a panel of 253 wheat accessions which were re-sequenced used to conduct genome-wide association studies (GWAS) using the factored spectrally transformed linear mixed models (FaST-LMM). For most accessions, the growth of seedlings was found to be inhibited under heat stress. Analysis of the phenotypic data revealed that under heat stress conditions, the main root length, total root length, and shoot length of seedlings decreased by 47.46%, 49.29%, and 15.19%, respectively, compared to those in normal conditions. However, 17 varieties were identified as heat stress tolerant germplasm. Through GWAS analysis, a total of 115 QTLs were detected under both heat stress and normal conditions. Furthermore, 15 stable QTL-clusters associated with heat response were identified. By combining gene expression, haplotype analysis, and gene annotation information within the physical intervals of the 15 QTL-clusters, two novel candidate genes, TraesCS4B03G0152700/TaWRKY74-B and TraesCS4B03G0501400/TaSnRK3.15-B, were responsive to temperature and identified as potential regulators of HST in wheat at the seedling stage. CONCLUSIONS: This study conducted a detailed genetic analysis and successfully identified two genes potentially associated with HST in wheat at the seedling stage, laying a foundation to further dissect the regulatory mechanism underlying HST in wheat under high temperature conditions. Our finding could serve as genomic landmarks for wheat breeding aimed at improving adaptation to heat stress in the face of climate change.

Identification and expression analysis of the Xyloglucan transglycosylase/hydrolase (XTH) gene family under abiotic stress in oilseed (Brassica napus L.).

XTH genes are key genes that regulate the hydrolysis and recombination of XG components and plays role in the structure and composition of plant cell walls. Therefore, clarifying the changes that occur in XTHs during plant defense against abiotic stresses is informative for the study of the plant stress regulatory mechanism mediated by plant cell wall signals. XTH proteins in Arabidopsis thaliana was selected as the seed sequences in combination with its protein structural domains, 80 members of the BnXTH gene family were jointly identified from the whole genome of the Brassica napus ZS11, and analyzed for their encoded protein physicochemical properties, phylogenetic relationships, covariance relationships, and interoperating miRNAs. Based on the transcriptome data, the expression patterns of BnXTHs were analyzed in response to different abiotic stress treatments. The relative expression levels of some BnXTH genes under Al, alkali, salt, and drought treatments after 0, 6, 12 and 24 h were analyzed by using qRT-PCR to explore their roles in abiotic stress tolerance in B. napus. BnXTHs showed different expression patterns in response to different abiotic stress signals, indicating that the response mechanisms of oilseed rape against different abiotic stresses are also different. This paper provides a theoretical basis for clarifying the function and molecular genetic mechanism of the BnXTH gene family in abiotic stress tolerance in rapeseed.

Effect of a QTL on wheat chromosome 5B associated with enhanced root dry mass on transpiration and nitrogen uptake under contrasting drought scenarios in wheat.

BACKGROUND: A sufficient nitrogen supply is crucial for high-quality wheat yields. However, the use of nitrogen fertilization can also negatively influence ecosystems due to leaching or volatile atmospheric emissions. Drought events, increasingly prevalent in many crop production areas, significantly impact nitrogen uptake. Breeding more efficient wheat varieties is necessary to achieve acceptable yields with limited nitrogen and water. Crop root systems play a crucial role as the primary organ for absorbing water and nutrients. To investigate the impact of an enhanced root system on nitrogen and water use efficiency in wheat under various irrigation conditions, this study conducted two experiments using precision phenotyping platforms for controlled drought stress treatment. Experiment 1 involved four contrasting winter wheat genotypes. It included the Chinese variety Ning0604, carrying a quantitative trait locus (QTL) on chromosome 5B associated with a higher root dry biomass, and three elite German varieties, Elixer, Genius, and Leandrus. Experiment 2 compared near-isogenic lines (NIL) of the three elite varieties, each containing introgressions of the QTL on chromosome 5B linked to root dry mass. In both experiments, nitrogen partitioning was tracked via isotope discrimination after fertilization with 5 Atom % 15N-labeled KNO3-. RESULTS: In experiment 1 the quantification by 15N isotope discrimination revealed significantly (p < 0.05) higher nitrogen derived from fertilizer in the root organ for Ning0604 than those of the three German varieties. In experiment 2, two out of three NILs showed a significantly (p < 0.05) higher uptake of N derived from fertilizer than their respective recipient line under well-watered conditions. Furthermore, significantly lower transpiration rates (p < 0.1) were observed in one NIL compared to its respective recipient. CONCLUSIONS: The combination of the DroughtSpotter facility coupled with 15N tracer-based tracking of N uptake and remobilization extends the insight into the impact of genetically altered root biomass on wheat NUE and WUE under different water availability scenarios. The study shows the potential for how a modified genetic constitution of the locus on wheat chromosome 5B can reduce transpiration and enhance N uptake. The dependence of the observations on the recipient and water availability suggests a need for further research to investigate the interaction with genetic background traits.

Genome-wide association study of drought tolerance in wheat (Triticum aestivum L.) identifies SNP markers and candidate genes.

Drought stress poses a severe threat to global wheat production, necessitating an in-depth exploration of the genetic basis for drought tolerance associated traits. This study employed a 90 K SNP array to conduct a genome-wide association analysis, unravelling genetic determinants of key traits related to drought tolerance in wheat, namely plant height, root length, and root and shoot dry weight. Using the mixed linear model (MLM) method on 125 wheat accessions subjected to both well-watered and drought stress treatments, we identified 53 SNPs significantly associated with stress susceptibility (SSI) and tolerance indices (STI) for the targeted traits. Notably, chromosomes 2A and 3B stood out with ten and nine associated markers, respectively. Across 17 chromosomes, 44 unique candidate genes were pinpointed, predominantly located on the distal ends of 1A, 1B, 1D, 2A, 3A, 3B, 4A, 6A, 6B, 7A, 7B, and 7D chromosomes. These genes, implicated in diverse functions related to plant growth, development, and stress responses, offer a rich resource for future investigation. A clustering pattern emerged, notably with seven genes associated with SSI for plant height and four genes linked to both STI of plant height and shoot dry weight, converging on specific regions of chromosome arms of 2AS and 3BL. Additionally, shared genes encoding polygalacturonase, auxilin-related protein 1, peptide deformylase, and receptor-like kinase underscored the interconnectedness between plant height and shoot dry weight. In conclusion, our findings provide insights into the molecular mechanisms governing wheat drought tolerance, identifying promising genomic loci for further exploration and crop improvement strategies.

Decrypting biocontrol functions and application modes by genomes data of three Trichoderma Strains/Species.

Trichoderma is an excellent biocontrol agent, but most Trichoderma genomes remained at the scaffold level, which greatly limits the research of biocontrol mechanism. Here, we reported the chromosome-level genome of Trichoderma harzianum CGMCC20739 (Tha739), T. asperellum CGMCC11653 (Tas653) and T. atroviride CGMCC40488 (Tat488), they were assembled into 7 chromosomes, genome size were 40 Mb (10,611 genes), 37.3 Mb (10,102 genes) and 36.3 Mb (9,896 genes), respectively. The positive selected genes of three strains were associated to response to stimulus, signaling transduction, immune system and localization. Furthermore, the number of transcription factors in Tha739, Tas653 and Tat488 strains had significant difference, which may contribute to the differential biocontrol function and stress tolerance. The genes related to signal transduction and gene clusters related to antimicrobial compounds in Tha739 were more than those in Tas653 and Tat488, which showed Tha739 may keenly sense other fungi and quickly secret antimicrobial compounds to inhibit other fungi. Tha739 also contained more genes associated to detoxification, antioxidant and nutrition utilization, indicating it had higher stress-tolerance to hostile environments. And the substrate for synthesizing IAA in Tha739 was mainly 3-indole acetonitrile and indole acetaldehyde, but in Tat488, it was indole-3-acetamide, moreover, Tha739 secreted more phosphatase and phytase and was more related to soil phosphorus metabolism, Tat488 secreted more urease and was more related to soil nitrogen metabolism. These candidate genes related to biocontrol function and stress-tolerance laid foundations for construction of functional strains. All above proved the difference in biocontrol function of Tha739, Tas653 and Tat488 strains, however, the defects in individual strains could be compensated for through Trichoderma-biome during the commercial application process of biocontrol Trichoderma strains.

Heterologous overexpression of Tawzy1-2 gene encoding an SK3 dehydrin enhances multiple abiotic stress tolerance in Escherichia coli and Nicotiania benthamiana.

MAIN CONCLUSION: The nuclear localized TaWZY1-2 helps plants resist abiotic stress by preserving the cell's ability to remove reactive oxygen species and decrease lipid oxidation under such conditions. In light of the unpredictable environmental conditions in which food crops grow, precise strategies must be developed by crops to effectively cope with abiotic stress and minimize damage over their lifespan. A key component in this endeavor is the group II of late embryogenesis abundant (LEA) proteins, known as dehydrins, which play crucial roles in enhancing the tolerance of plants to abiotic stress. Tawzy1-2 is a dehydrin-encoding gene which is constitutively expressed in various tissues of wheat. However, the biological function of TaWZY1-2 is not yet fully understood. In this study, TaWZY1-2 was isolated and identified in the wheat genome, and its functional role in conferring tolerance to abiotic stresses was detected in both prokaryotic and eukaryotic cells. Results showed that TaWZY1-2 is a nuclear localized hydrophilic protein that accumulates in response to multiple stresses. Escherichia coli cells expressing TaWZY1-2 showed enhanced tolerance to multiple stress conditions. Overexpression of TaWZY1-2 in Nicotiania benthamiana improved growth, germination and survival rate of the transgenic plants exposed to four kinds of abiotic stress conditions. Our results show that Tawzy1-2 transgenic plants exhibit improved capability in clearing reactive oxygen species and reducing lipid degradation, thereby enhancing their resistance to abiotic stress. This demonstrates a significant role of TaWZY1-2 in mitigating abiotic stress-induced damage. Consequently, these findings not only establish a basis for future investigation into the functional mechanism of TaWZY1-2 but also contribute to the expansion of functional diversity within the dehydrin protein family. Moreover, they identify potential candidate genes for crop optimization.

γ-Aminobutyric acid (GABA) priming alleviates acid-aluminum toxicity to roots of creeping bentgrass via enhancements in antioxidant defense and organic metabolites remodeling.

MAIN CONCLUSION: γ-Aminobutyric acid alleviates acid-aluminum toxicity to roots associated with enhanced antioxidant metabolism as well as accumulation and transportation of citric and malic acids. Aluminum (Al) toxicity has become the main limiting factor for crop growth and development in acidic soils and is further being aggravated worldwide due to continuous industrial pollution. The current study was designed to examine effects of GABA priming on alleviating acid-Al toxicity in terms of root growth, antioxidant defense, citrate and malate metabolisms, and extensive metabolites remodeling in roots under acidic conditions. Thirty-seven-day-old creeping bentgrass (Agrostis stolonifera) plants were used as test materials. Roots priming with or without 0.5 mM GABA for 3 days were cultivated in standard nutrient solution for 15 days as control or subjected to nutrient solution containing 5 mM AlCl3·6H2O for 15 days as acid-Al stress treatment. Roots were sampled for determinations of root characteristics, physiological and biochemical parameters, and metabolomics. GABA priming significantly alleviated acid-Al-induced root growth inhibition and oxidative damage, despite it promoted the accumulation of Al in roots. Analysis of metabolomics showed that GABA priming significantly increased accumulations of organic acids, amino acids, carbohydrates, and other metabolites in roots under acid-Al stress. In addition, GABA priming also significantly up-regulated key genes related to accumulation and transportation of malic and citric acids in roots under acid-Al stress. GABA-regulated metabolites participated in tricarboxylic acid cycle, GABA shunt, antioxidant defense system, and lipid metabolism, which played positive roles in reactive oxygen species scavenging, energy conversion, osmotic adjustment, and Al ion chelation in roots.

OsGEX3 affects anther development and improves osmotic stress tolerance in rice.

MAIN CONCLUSION: Overexpression and loss of function of OsGEX3 reduce seed setting rates and affect pollen fertility in rice. OsGEX3 positively regulates osmotic stress response by regulating ROS scavenging. GEX3 proteins are conserved in plants. AtGEX3 encodes a plasma membrane protein that plays a crucial role in pollen tube guidance. However, the function of its homolog in rice, OsGEX3, has not been determined. Our results demonstrate that OsGEX3 is localized in the plasma membrane and the nucleus as shown by a transiently transformed assay using Nicotiana benthamiana leaves. The up-regulation of OsGEX3 was detected in response to treatments with polyethylene glycol (PEG) 4000, hydrogen peroxide, and abscisic acid (ABA) via RT-qPCR analysis. Interestingly, we observed a significant decline in the seed setting rates of OsGEX3-OE lines and mutants, compared to the wild type. Further investigations reveal that overexpression and loss of function of OsGEX3 affect pollen maturation. TEM observation revealed a significant decrease in the fertile pollen rates of OsGEX3-OE transgenic lines and Osgex3 mutants due to a delay in pollen development at the late vacuolated stage. Overexpression of OsGEX3 improved osmotic stress and oxidative stress tolerance by enhancing reactive oxygen species (ROS) scavenging in rice seedlings, whereas Osgex3 mutants exhibited an opposite phenotype in osmotic stress. These findings highlight the multifunctional roles of OsGEX3 in pollen development and the response to abiotic stress. The functional characterization of OsGEX3 provides a fundamental basis for rice molecular breeding and can facilitate efforts to cultivate drought resistance and yield-related varieties.

Major transcription factor families at the nexus of regulating abiotic stress response in millets: a comprehensive review.

Millets stand out as a sustainable crop with the potential to address the issues of food insecurity and malnutrition. These small-seeded, drought-resistant cereals have adapted to survive a broad spectrum of abiotic stresses. Researchers are keen on unravelling the regulatory mechanisms that empower millets to withstand environmental adversities. The aim is to leverage these identified genetic determinants from millets for enhancing the stress tolerance of major cereal crops through genetic engineering or breeding. This review sheds light on transcription factors (TFs) that govern diverse abiotic stress responses and play role in conferring tolerance to various abiotic stresses in millets. Specifically, the molecular functions and expression patterns of investigated TFs from various families, including bHLH, bZIP, DREB, HSF, MYB, NAC, NF-Y and WRKY, are comprehensively discussed. It also explores the potential of TFs in developing stress-tolerant crops, presenting a comprehensive discussion on diverse strategies for their integration.