TaERF87 and TaAKS1 synergistically regulate TaP5CS1/TaP5CR1-mediated proline biosynthesis to enhance drought tolerance in wheat

Integrated metabolomics and transcriptomics reveal that HhERF9 positively regulates salt tolerance in Hibiscus hamabo Siebold & Zuccarini

Hibiscus hamabo Siebold & Zuccarini is one of the few semi-mangrove plants in the genus Hibiscus that can survive in saline-alkali soil and flooded land, but the mechanism underlying its adaptation to salt soil remains unknown. Here, to uncover this unsolved mystery, we characterized the changes in the accumulation of specific metabolites under salt stress in H. hamabo by integrating physiological, metabolic, and transcriptomic data, and found that osmotic adjustment and abscisic acid (ABA) is highly associated with the salt stress response. Further, a weighted gene co-expression network analysis was performed on the root transcriptome data, which identified three key candidate transcription factors responsive to salt stress. Among them, the expression HhERF9 was significantly upregulated under salt stress and ABA treatment and was involved in regulating the expression of genes related to the salt stress response. Further research indicated that HhERF9 enhances the accumulation of proline and soluble sugars by regulating the expression of genes such as NHX2 and P5CS. These findings provide a reference for improving H. hamabo through targeted genetic engineering and lay a theoretical foundation for its future promotion and cultivation in saline-alkali areas.

Functions of Basic Helix-Loop-Helix (bHLH) Proteins in the Regulation of Plant Responses to Cold, Drought, Salt, and Iron Deficiency: A Comprehensive Review

Abiotic stresses including cold, drought, salt, and iron deficiency severely impair plant development, crop productivity, and geographic distribution. Several bodies of research have shed light on the pleiotropic functions of BASIC HELIX-LOOP-HELIX (bHLH) proteins in plant responses to these abiotic stresses. In this review, we mention the regulatory roles of bHLH TFs in response to stresses such as cold, drought, salt resistance, and iron deficiency, as well as in enhancing grain yield in plants, especially crops. The bHLH proteins bind to E/G-box motifs in the target promoter and interact with various other factors to form a complex regulatory network. Through this network, they cooperatively activate or repress the transcription of downstream genes, thereby regulating various stress responses. Finally, we present some perspectives for future research focusing on the molecular mechanisms that integrate and coordinate these abiotic stresses. Understanding these molecular mechanisms is crucial for the development of stress-tolerant crops.

Transgenerational Seed Exposure to Elevated CO2 Involves Stress Memory Regulation at Metabolic Levels to Confer Drought Resistance in Wheat

Drought is the worst environmental stress constraint that inflicts heavy losses to global food production, such as wheat. The metabolic responses of seeds produced overtransgenerational exposure to e[CO2] to recover drought's effects on wheat are still unexplored. Seeds were produced constantly for four generations (F1 to F4) under ambient CO2 (a[CO2], 400 μmol L-1) and elevated CO2 (e[CO2], 800 μmol L-1) concentrations, and then further regrown under natural CO2 conditions to investigate their effects on the stress memory metabolic processes liable for increasing drought resistance in the next generation (F5). At the anthesis stage, plants were subjected to normal (100% FC, field capacity) and drought stress (60% FC) conditions. Under drought stress, plants of transgenerational e[CO2] exposed seeds showed markedly increased superoxide dismutase (16%), catalase (24%), peroxidase (9%), total antioxidants (14%), and proline (35%) levels that helped the plants to sustain normal growth through scavenging of hydrogen peroxide (11%) and malondialdehyde (26%). The carbohydrate metabolic enzymes such as aldolase (36%), phosphoglucomutase (12%), UDP-glucose pyrophosphorylase (25%), vacuolar invertase (33%), glucose-6-phosphate-dehydrogenase (68%), and cell wall invertase (17%) were decreased significantly; however, transgenerational seeds produced under e[CO2] showed a considerable increase in their activities in drought-stressed wheat plants. Moreover, transgenerational e[CO2] exposed seeds under drought stress caused a marked increase in leaf Ψw (15%), chlorophyll a (19%), chlorophyll b (8%), carotenoids (12%), grain spike (16%), hundred grain weight (19%), and grain yield (10%). Hence, transgenerational seeds exposed to e[CO2] upregulate the drought recovery metabolic processes to improve the grain yield of wheat under drought stress conditions.

Biochemical characterization and metabolic reprogramming of amino acids in Soybean roots under drought stress

Amino acids play important roles in stress resistance, plant growth, development, and quality, with roots serving as the primary organs for drought response. We conducted biochemical and multi-omics analyses to investigate the metabolic processes of root amino acids in drought-resistant (HN44) and drought-sensitive (HN65) soybean (Glycine max) varieties. Our analysis revealed an increase in total amino acid content in both varieties, with phenylalanine, proline, and methionine accumulating in both. Additionally, several amino acids exhibited significant decreases in HN65 but slight increases in HN44. Multi-omics association analysis identified 13 amino acid-related pathways. We thoroughly examined the changes in genes and metabolites involved in various amino acid metabolism/synthesis and determined core genes and metabolites through correlation networks. The phenylalanine, tyrosine, and tryptophan metabolic pathways and proline, glutamic acid and sulfur-containing amino acid pathways were particularly important for drought resistance. Some candidate genes, such as ProDH and P4HA family genes, and metabolites, such as O-acetyl-L-serine, directly affected up- and downstream metabolism to induce drought resistance. This study provided a basis for soybean drought resistance breeding.

Transcription factors as molecular switches regulating plant responses to drought stress

Plants often experience abiotic stress, which severely affects their growth. With the advent of global warming, drought stress has become a pivotal factor affecting crop yield and quality. Increasing numbers of studies have focused on elucidating the molecular mechanisms underlying plant responses to drought stress. As molecular switches, transcription factors (TFs) are key participants in drought-resistance regulatory networks in crops. TFs regulate the transcription of downstream genes and are regulated by various upstream regulatory factors. Therefore, understanding the mechanisms of action of TFs in regulating drought stress can help enhance the adaptive capacity of crops under drought conditions. In this review, we summarize the structural characteristics of several common TFs, their multiple drought-response pathways, and recently employed research strategies. We describe the application of new technologies such as analysis of stress granule dynamics and function, multi-omics data, gene editing, and molecular crosstalk between TFs in drought resistance. This review aims to familiarize readers with the regulatory network of TFs in drought resistance and to provide a reference for examining the molecular mechanisms of drought resistance in plants and improving agronomic traits.

VvERF117 positively regulates grape cold tolerance through direct regulation of the antioxidative gene BAS1

Cold stress significantly threatens grape quality, yield, and geographical distribution. Although ethylene-responsive factors (ERFs) are recognized for their pivotal roles in cold stress, the regulatory mechanisms of many ERFs contributing to tolerance remain unclear. In this study, we identified the cold-responsive gene VvERF117 and elucidated its positive regulatory function in cold tolerance. VvERF117 exhibits transcriptional activity and localizes to the nucleus. VvERF117 overexpression improved cold tolerance in transgenic Arabidopsis, grape calli, and grape leaves, whereas VvERF117 silencing increased cold sensitivity in grape calli and leaves. Furthermore, VvERF117 overexpression remarkably upregulated the expression of several stress-related genes. Importantly, BAS1, encoding a 2-Cys peroxidase (POD), was confirmed as a direct target gene of VvERF117. Meanwhile, compared to the wild-type, POD activity and H2O2 content were remarkably increased and decreased in VvERF117-overexpressing grape calli and leaves, respectively. Conversely, VvERF117 silencing displayed the opposite trend in grape calli and leaves under cold stress. These findings indicate that VvERF117 plays a positive role in cold resistance by, at least in part, enhancing antioxidant capacity through regulating the POD-encoding gene VvBAS1, leading to effective mitigation of reactive oxygen species.

Two transcription factors, RhERF005 and RhCCCH12, regulate rose resistance to Botrytis cinerea by modulating cytokinin levels

Gray mold caused by the necrotrophic fungal pathogen Botrytis cinerea is one of the most destructive diseases in rose (Rosa spp.). Rose infection by B. cinerea leads to severe economic losses due to necrosis, tissue collapse, and rot. In rose, cytokinins (CKs) positively regulate a defense response to B. cinerea, but little is known about the underlying molecular mechanisms. Here, we characterized two ethylene/jasmonic acid-regulated transcription factors, RhEFR005 and RhCCCH12, that bind to the promoter region of PATHOGENESIS-RELATED 10.1 (RhPR10.1) and promote its transcription, leading to decreased susceptibility to B. cinerea. The RhEFR005/RhCCCH12-RhPR10.1 module regulated cytokinin content in rose, and the susceptibility of RhEFR005-, RhCCCH12-, and RhPR10.1-silenced rose petals can be rescued by exogenous CK. In summary, our results reveal that the RhERF005/RhCCCH12-RhPR10.1 module regulates the CK-induced defense response of rose to B. cinerea.

A long non-coding RNA functions as a competitive endogenous RNA to modulate TaNAC018 by acting as a decoy for tae-miR6206

Increasing evidence indicates a strong correlation between the deposition of cuticular waxes and drought tolerance. However, the precise regulatory mechanism remains elusive. Here, we conducted a comprehensive transcriptome analysis of two wheat (Triticum aestivum) near-isogenic lines, the glaucous line G-JM38 rich in cuticular waxes and the non-glaucous line NG-JM31. We identified 85,143 protein-coding mRNAs, 4,485 lncRNAs, and 1,130 miRNAs. Using the lncRNA-miRNA-mRNA network and endogenous target mimic (eTM) prediction, we discovered that lncRNA35557 acted as an eTM for the miRNA tae-miR6206, effectively preventing tae-miR6206 from cleaving the NAC transcription factor gene TaNAC018. This lncRNA-miRNA interaction led to higher transcript abundance for TaNAC018 and enhanced drought-stress tolerance. Additionally, treatment with mannitol and abscisic acid (ABA) each influenced the levels of tae-miR6206, lncRNA35557, and TaNAC018 transcript. The ectopic expression of TaNAC018 in Arabidopsis also improved tolerance toward mannitol and ABA treatment, whereas knocking down TaNAC018 transcript levels via virus-induced gene silencing in wheat rendered seedlings more sensitive to mannitol stress. Our results indicate that lncRNA35557 functions as a competing endogenous RNA to modulate TaNAC018 expression by acting as a decoy target for tae-miR6206 in glaucous wheat, suggesting that non-coding RNA has important roles in the regulatory mechanisms responsible for wheat stress tolerance.

Exogenous 24-Epibrassinolide Enhanced Drought Tolerance and Promoted BRASSINOSTEROID-INSENSITIVE2 Expression of Quinoa

Brassinosteroids (BRs) are involved in the regulation of biotic and abiotic stresses in plants. The molecular mechanisms of BRs that alleviate the drought stress in quinoa have rarely been reported. Here, quinoa seedlings were treated with 24-epibrassinolide (EBR) and we transiently transferred CqBIN2 to the quinoa seedlings' leaves using VIGS technology to analyze the molecular mechanism of the BR mitigation drought stress. The results showed that EBR treatment significantly increased the root growth parameters, the antioxidant enzyme activities, and the osmolyte content, resulting in a decrease in the H2O2, O2∙-, and malondialdehyde content in quinoa. A transcriptome analysis identified 8124, 2761, and 5448 differentially expressed genes (DEGs) among CK and Drought, CK and EBR + Drought, and Drought and EBR + Drought groups. WGCNA divided these DEGs into 19 modules in which these characterized genes collectively contributed significantly to drought stress. In addition, the EBR application also up-regulated the transcript levels of CqBIN2 and proline biosynthesis genes. Silenced CqBIN2 by VIGS could reduce the drought tolerance, survival rate, and proline content in quinoa seedlings. These findings not only revealed that exogenous BRs enhance drought tolerance, but also provided insight into the novel functions of CqBIN2 involved in regulating drought tolerance in plants.

The E3 ligase TaGW2 mediates transcription factor TaARR12 degradation to promote drought resistance in wheat

Drought stress limits crop yield, but the molecular modulators and their mechanisms underlying the trade-off between drought resistance and crop growth and development remain elusive. Here, a grain width and weight2 (GW2)-like really interesting new gene finger E3 ligase, TaGW2, was identified as a pivotal regulator of both kernel development and drought responses in wheat (Triticum aestivum). TaGW2 overexpression enhances drought resistance but leads to yield drag under full irrigation conditions. In contrast, TaGW2 knockdown or knockout attenuates drought resistance but remarkably increases kernel size and weight. Furthermore, TaGW2 directly interacts with and ubiquitinates the type-B Arabidopsis response regulator TaARR12, promoting its degradation via the 26S proteasome. Analysis of TaARR12 overexpression and knockdown lines indicated that TaARR12 represses the drought response but does not influence grain yield in wheat. Further DNA affinity purification sequencing combined with transcriptome analysis revealed that TaARR12 downregulates stress-responsive genes, especially group-A basic leucine zipper (bZIP) genes, resulting in impaired drought resistance. Notably, TaARR12 knockdown in the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated nuclease 9 (Cas9)-mediated tagw2 knockout mutant leads to significantly higher drought resistance and grain yield compared to wild-type plants. Collectively, these findings show that the TaGW2-TaARR12 regulatory module is essential for drought responses, providing a strategy for improving stress resistance in high-yield wheat varieties.

Development of KASP markers assisted with soybean drought tolerance in the germination stage based on GWAS

Soybean [Glycine max(L.)Merr.] is a leading oil-bearing crop and cultivated globally over a vast scale. The agricultural landscape in China faces a formidable challenge with drought significantly impacting soybean production. In this study, we treated a natural population of 264 Chinese soybean accessions using 15% PEG-6000 and used GR, GE, GI, RGR, RGE, RGI and ASFV as evaluation index. Using the ASFV, we screened 17 strong drought-tolerant soybean germplasm in the germination stage. Leveraging 2,597,425 high-density SNP markers, we conducted Genome-Wide Association Studies (GWAS) and identified 92 SNPs and 9 candidate genes significantly associated with drought tolerance. Furthermore, we developed two KASP markers for S14_5147797 and S18_53902767, which closely linked to drought tolerance. This research not only enriches the pool of soybean germplasm resources but also establishes a robust foundation for the molecular breeding of drought tolerance soybean varieties.

RcMYB8 enhances salt and drought tolerance in rose (Rosa chinensis) by modulating RcPR5/1 and RcP5CS1

Plant Myeloblastosis (MYB) proteins function crucially roles upon variegated abiotic stresses. Nonetheless, their effects and mechanisms in rose (Rosa chinensis) are not fully clarified. In this study, we characterized the effects of rose RcMYB8 under salt and drought tolerances. For induction of the RcMYB8 expression, NaCl and drought stress treatment were adopted. Rose plants overexpressing RcMYB8 displayed enhanced tolerance to salinity and drought stress, while silencing RcMYB8 resulted in decreased tolerance, as evidenced by lowered intra-leaf electrolyte leakage and callose deposition, as well as photosynthetic sustainment under stressed conditions. Here, we further show that RcMYB8 binds similarly to the promoters of RcPR5/1 and RcP5C51 in vivo and in vitro. Inhibiting RcP5CS1 by virus-induced gene silencing led to decreased drought tolerance through the reactive oxygen species (ROS) homeostatic regulation. RcP5CS1-silenced plants showed an increase in ion leakage and reduce of proline content, together with the content of malondialdehyde (MDA) increased, lowered activities of Catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Our study highlights the transcriptional modulator role of RcMYB8 in drought and salinity tolerances, which bridges RcPR5/1 and RcP5CS1 by promoting ROS scavenging. Besides, it is probably applicable to the rose plant engineering for enhancing their abiotic stress tolerances.

Genome-wide identification and comprehensive analysis of the phytochrome-interacting factor (PIF) gene family in wheat

Phytochrome-interacting factors (PIFs) are essential transcription factors for plant growth, development, and stress responses. Although PIF genes have been extensively studied in many plant species, they have not been thoroughly investigated in wheat. Here, we identified 18 PIF genes in cultivated hexaploid wheat (Triticum aestivum L). Phylogenetic analysis, exon-intron structures, and motif compositions revealed the presence of four distinct groups of TaPIFs. Genome-wide collinearity analysis of PIF genes revealed the evolutionary history of PIFs in wheat, Oryza sativa, and Brachypodium distachyon. Cis-regulatory element analysis suggested that TaPIF genes indicated participated in plant development and stress responses. Subcellular localization assays indicated that TaPIF2-1B and TaPIF4-5B were transcriptionally active. Both were found to be localized to the nucleus. Gene expression analyses demonstrated that TaPIFs were primarily expressed in the leaves and were induced by various biotic and abiotic stresses and phytohormone treatments. This study provides new insights into PIF-mediated stress responses and lays a strong foundation for future investigation of PIF genes in wheat.

The NtDEGP5 gene improves drought tolerance in tobacco (Nicotiana tabacum L.) by dampening plastid extracellular Ca2+ and flagellin signaling and thereby reducing ROS production

Tobacco is an essential cash crop, but drought has become a major factor in the decline of global tobacco production as a result of changes in the global climate. The HtrA protease is an oligomeric serine endopeptidase that responds to stress in plants. DEGP5 is a member of the gene family that encodes HtrA protease, which promotes plant adaptation to adversity. The aim of this study was to investigate the role and mechanism employed by the DEGP5 gene in response to drought stress in tobacco. NtDEGP5-overexpression lines were obtained by genetic transformation and the phenotypes and transcriptomes of NtDEGP5-overexpression lines and wild-type (K326) tobacco seedlings were compared under drought stress. The results demonstrated that plants overexpressing NtDEGP5 exhibited greater drought tolerance. The differentially expressed genes involved in the regulation of drought tolerance by DEGP5 were enriched in metabolic pathways, such as plant-pathogen interaction and glutathione metabolism, with the plant-pathogen interaction pathway having the most differentially expressed genes. An analysis of the plant-pathogen interaction pathway revealed that these genes contributed to the suppression of plastid extracellular Ca2+ signaling and flagellin signaling to inhibit reactive oxygen species production, and that lower levels of reactive oxygen species act as a signal to regulate the activation of the antioxidant system, further balancing the production and removal of reactive oxygen species in tobacco seedlings under drought stress. These findings suggest that the NtDEGP5 gene can enhance the drought tolerance of tobacco by regulating the homeostasis of reactive oxygen species by inhibiting extracellular plastids.

Wheat adaptation to environmental stresses under climate change: Molecular basis and genetic improvement

Wheat (Triticum aestivum) is a staple food for about 40% of the world's population. As the global population has grown and living standards improved, high yield and improved nutritional quality have become the main targets for wheat breeding. However, wheat production has been compromised by global warming through the more frequent occurrence of extreme temperature events, which have increased water scarcity, aggravated soil salinization, caused plants to be more vulnerable to diseases, and directly reduced plant fertility and suppressed yield. One promising option to address these challenges is the genetic improvement of wheat for enhanced resistance to environmental stress. Several decades of progress in genomics and genetic engineering has tremendously advanced our understanding of the molecular and genetic mechanisms underlying abiotic and biotic stress responses in wheat. These advances have heralded what might be considered a "golden age" of functional genomics for the genetic improvement of wheat. Here, we summarize the current knowledge on the molecular and genetic basis of wheat resistance to abiotic and biotic stresses, including the QTLs/genes involved, their functional and regulatory mechanisms, and strategies for genetic modification of wheat for improved stress resistance. In addition, we also provide perspectives on some key challenges that need to be addressed.

Molecular Mechanism Underlying the Sorghum sudanense (Piper) Stapf. Response to Osmotic Stress Determined via Single-Molecule Real-Time Sequencing and Next-Generation Sequencing

Drought, as a widespread environmental factor in nature, has become one of the most critical factors restricting the yield of forage grass. Sudangrass (Sorghum sudanense (Piper) Stapf.), as a tall and large grass, has a large biomass and is widely used as forage and biofuel. However, its growth and development are limited by drought stress. To obtain novel insight into the molecular mechanisms underlying the drought response and excavate drought tolerance genes in sudangrass, the first full-length transcriptome database of sudangrass under drought stress at different time points was constructed by combining single-molecule real-time sequencing (SMRT) and next-generation transcriptome sequencing (NGS). A total of 32.3 Gb of raw data was obtained, including 20,199 full-length transcripts with an average length of 1628 bp after assembly and correction. In total, 11,921 and 8559 up- and down-regulated differentially expressed genes were identified between the control group and plants subjected to drought stress. Additionally, 951 transcription factors belonging to 50 families and 358 alternative splicing events were found. A KEGG analysis of 158 core genes exhibiting continuous changes over time revealed that 'galactose metabolism' is a hub pathway and raffinose synthase 2 and β-fructofuranosidase are key genes in the response to drought stress. This study revealed the molecular mechanism underlying drought tolerance in sudangrass. Furthermore, the genes identified in this study provide valuable resources for further research into the response to drought stress.

Transcriptomic and co-expression network analyses on diverse wheat landraces identifies candidate master regulators of the response to early drought

Introduction

Over four billion people around the world rely on bread wheat (Triticum aestivum L.) as a major constituent of their diet. The changing climate, however, threatens the food security of these people, with periods of intense drought stress already causing widespread wheat yield losses. Much of the research into the wheat drought response has centred on the response to drought events later in development, during anthesis or grain filling. But as the timing of periods of drought stress become increasingly unpredictable, a more complete understanding of the response to drought during early development is also needed.

Methods

Here, we utilized the YoGI landrace panel to identify 10,199 genes which were differentially expressed under early drought stress, before weighted gene co-expression network analysis (WGCNA) was used to construct a co-expression network and identify hub genes in modules particularly associated with the early drought response.

Results

Of these hub genes, two stood out as novel candidate master regulators of the early drought response - one as an activator (TaDHN4-D1; TraesCS5D02G379200) and the other as a repressor (uncharacterised gene; TraesCS3D02G361500).

Discussion

As well as appearing to coordinate the transcriptional early drought response, we propose that these hub genes may be able to regulate the physiological early drought response due to potential control over the expression of members of gene families well-known for their involvement in the drought response in many plant species, namely dehydrins and aquaporins, as well as other genes seemingly involved in key processes such as, stomatal opening, stomatal closing, stomatal morphogenesis and stress hormone signalling.

PagMYB151 facilitates proline accumulation to enhance salt tolerance of poplar

Poplar is one of the main urban and rural greening and shade tree species in the northern hemisphere, but its growth and development is always restricted by salt stress. R2R3-MYB transcription factor family is commonly involved in many biological processes during plant growth and stress endurance. In this study, PagMYB151 (Potri.014G035100) one of R2R3-MYB members related to salt stress and expressed in both nucleus and cell membrane was cloned from Populus alba × P. glandulosa to perfect the salt tolerance mechanism. Morphological and physiological indexes regulated by PagMYB151 were detected using the PagMYB151 overexpression (OX) and RNA interference (RNAi) transgenic poplar lines. Under salt stress conditions, compared with RNAi and the non-transgenic wild-type (WT) plants, the plant height, both aboveground and underground part fresh weight of OX was significantly increased. In addition, OX has a longer and finer root structure and a larger root surface area. The root activity of OX was also enhanced, which was significantly different from RNAi but not from WT under salt treatment. Under normal conditions, the stomatal aperture of OX was larger than WT, whereas this phenotype was not obvious after salt stress treatment. In terms of physiological indices, OX enhanced the accumulation of proline but reduced the toxicity of malondialdehyde to plants under salt stress. Combing with the transcriptome sequencing data, 6 transcription factors induced by salt stress and co-expressed with PagMYB151 were identified that may cooperate with PagMYB151 to function in salt stress responding process. This study provides a basis for further exploring the molecular mechanism of poplar PagMYB151 transcription factor under abiotic stress.

Transcriptome Analysis of Roots from Wheat (Triticum aestivum L.) Varieties in Response to Drought Stress

Under climate change, drought is one of the most limiting factors that influences wheat (Triticum aestivum L.) production. Exploring stress-related genes is vital for wheat breeding. To identify genes related to the drought tolerance response, two common wheat cultivars, Zhengmai 366 (ZM366) and Chuanmai 42 (CM42), were selected based on their obvious difference in root length under 15% PEG-6000 treatment. The root length of the ZM366 cultivar was significantly longer than that of CM42. Stress-related genes were identified by RNA-seq in samples treated with 15% PEG-6000 for 7 days. In total, 11,083 differentially expressed genes (DEGs) and numerous single nucleotide polymorphisms (SNPs) and insertions/deletions (InDels) were identified. GO enrichment analysis revealed that the upregulated genes were mainly related to the response to water, acidic chemicals, oxygen-containing compounds, inorganic substances, and abiotic stimuli. Among the DEGs, the expression levels of 16 genes in ZM366 were higher than those in CM42 after the 15% PEG-6000 treatment based on RT-qPCR. Furthermore, EMS-induced mutants in Kronos (T. turgidum L.) of 4 representative DEGs possessed longer roots than the WT after the 15% PEG-6000 treatment. Altogether, the drought stress genes identified in this study represent useful gene resources for wheat breeding.

Transcriptome and Proteome Analysis Revealed That Hormone and Reactive Oxygen Species Synergetically Regulate Dormancy of Introgression Line in Rice (Oryza sativa L.)

Dormancy is a complex agronomy phenotype controlled by multiple signaling and a key trait repressing pre-harvest sprouting (PHS). However, the signaling network of dormancy remains unclear. In this study, we used Zhonghua11 (ZH11) with a weak dormancy, and Introgression line (IL) with a strong dormancy to study the mechanism of hormones and reactive oxygen species (ROS) crosstalk regulating rice dormancy. The germination experiment showed that the germination rate of ZH11 was 76.86%, while that of IL was only 1.25%. Transcriptome analysis showed that there were 1658 differentially expressed genes (DEGs) between IL and ZH11, of which 577 were up-regulated and 1081 were down-regulated. Additionally, DEGs were mainly enriched in oxidoreductase activity, cell periphery, and plant hormone signal transduction pathways. Tandem mass tags (TMT) quantitative proteomics analysis showed 275 differentially expressed proteins (DEPs) between IL and ZH11, of which 176 proteins were up-regulated, 99 were down-regulated, and the DEPs were mainly enriched in the metabolic process and oxidation-reduction process. The comprehensive transcriptome and proteome analysis showed that their correlation was very low, and only 56 genes were co-expressed. Hormone content detection showed that IL had significantly lower abscisic acid (ABA) contents than the ZH11 while having significantly higher jasmonic acid (JA) contents than the ZH11. ROS content measurement showed that the hydrogen peroxide (H₂O₂) content of IL was significantly lower than the ZH11, while the production rate of superoxide anion (O₂^.-) was significantly higher than the ZH11. These results indicate that hormones and ROS crosstalk to regulate rice dormancy. In particular, this study has deepened our mechanism of ROS and JA crosstalk regulating rice dormancy and is conducive to our precise inhibition of PHS.

Genome-wide association analysis revealed genetic variation and candidate genes associated with the yield traits of upland cotton under drought conditions

Drought is one of the major abiotic stresses seriously affecting cotton yield. At present, the main cotton-producing areas in China are primarily arid and semiarid regions. Therefore, the identification of molecular markers and genes associated with cotton yield traits under drought conditions is of great importance for stabilize cotton yield under such conditions. In this study, resequencing data were used to conduct a genome-wide association study (GWAS) on 8 traits of 150 cotton germplasms. Under drought stress, 18 SNPs were significantly correlated with yield traits (single-boll weight (SBW) and seed (SC)), and 8 SNPs were identified as significantly correlated with effective fruit shoot number (EFBN) traits (a trait that is positively correlated with yield). Finally, a total of 15 candidate genes were screened. The combined results of the GWAS and transcriptome data analysis showed that four genes were highly expressed after drought stress, and these genes had significantly increased expression at 10, 15 and 25 DPA of fiber development. qRT-PCR was performed on two samples with drought tolerance extremes (drought-resistant Xinluzao 45 and drought-sensitive Xinluzao 26), revealing that three of the genes had the same differential expression pattern. This study provides a theoretical basis for the genetic analysis of cotton yield traits under drought stress, and provides gene resources for improved breeding of cotton yield traits under drought stress.