Drought is a major constraint on global wheat productivity. Although the phytohormone abscisic acid (ABA) is a well-established regulator of drought responses, its regulatory mechanisms in wheat remain unclear. Here, we identify the abscisic acid-, stress- and ripening-induced (ASR) transcription factor TaASR4-3D as a negative regulator of drought tolerance in wheat. Constitutive overexpression of TaASR4-3D increased drought sensitivity, disrupted reactive oxygen species (ROS) homeostasis and reduced stomatal closure capacity, whereas taasr4-3d mutants showed enhanced drought tolerance. RNA sequencing and biochemical assays revealed that TaNCED2-5D and TaRD17-6D are direct targets of TaASR4-3D, which represses their expression by binding to CACCG-containing motifs in their promoters. Furthermore, the RING-type E3 ubiquitin ligase TaSDIR1-4A physically interacts with TaASR4-3D and promotes its ubiquitination and 26S proteasome-mediated degradation. Collectively, these results show that TaASR4-3D negatively regulates ABA-related drought responses and affects ROS homeostasis in wheat seedlings, whereas TaSDIR1-4A interacts with TaASR4-3D and promotes its degradation. These findings provide molecular insights for future improvement of drought tolerance in wheat.

Megadroughts increasingly threaten crop productivity, yet microbiome-based strategies for improving plant resilience remain limited by a lack of mechanistic understanding and inconsistent performance across environments. Here, we combine population-scale screening, synthetic community approaches and multi-omics analyses to define a causal microbiome–host pathway underlying drought tolerance in wheat. Screening of 251 genotypes revealed that microbiomes associated with drought-adapted plants enhance host performance under water deficit and can reconfigure rhizosphere communities. Across genotypes and soil types, Enterobacter consistently emerged as a key taxon associated with improved drought tolerance, and synthetic community experiments demonstrated that functional outcomes are driven by specific taxa rather than community diversity. Mechanistically, Enterobacter colonization activates host phenylpropanoid metabolism, leading to accumulation of caffeic acid and coordinated induction of drought-responsive transcriptional networks. Genetic disruption of phenylalanine ammonia-lyase abolishes these effects, establishing a direct host requirement for microbiome-mediated resilience. These interactions generate metabolite-mediated feedback that conditions the rhizosphere and reinforces plant performance. Field experiments under extreme drought further demonstrate improved photosynthetic capacity and grain yield following Enterobacter -based inoculation. Together, our findings establish a mechanistic link between microbiome activity and host metabolic regulation, and provide a framework for developing microbiome-assisted strategies to enhance crop resilience under climate stress.

The development of reproductive organs plays a vital role in the production of gametes. However, the regulators of this process are poorly understood in wheat. Here, we identified a wheat sterile mutant ste with indehiscent anthers and shrunken pollen grains. Cytological analysis suggested that the tapetum cells degenerated earlier; Ubisch bodies exhibited abnormal shapes, while the microspore mother cells displayed meiosis defects, leading to the failure of tetrads formation in the ste. Bulked segregant analysis (BSA) and map-based cloning indicated that the TaAGO5c encoding an Argonaute protein is responsible for the sterility in ste. Gene editing-mediated knockout of three TaAGO5c homeologous genes resulted in a severely decreased self-seeding rate, confirming its function in reproductive development. TaAGO5c was predominantly expressed in the young spikes and anthers from the unicellular microspore stage to mature pollen stage. Subcellular localization in wheat protoplasts suggested that TaAGO5c is localized in the cytoplasm. Transcriptome sequencing analysis suggested that DEGs between the ste and control in the 30-40 mm and 60-70 mm young spikes were significantly enriched in several pathways associated with tapetum development and meiosis. Furthermore, some key genes related to these processes were downregulated in the ste mutant, which may be responsible for the abnormal development of tapetum and microspore. These results collectively suggest that TaAGO5c is a crucial regulator in reproductive development of wheat. This study also provides new insights into the genetic regulation of tapetum cells and Ubisch bodies development in wheat.

The quality of Coffee arabica L. beans, particularly the aroma, is a key determinant of commercial value. Fatty acids, as precursors of volatile aroma compounds, play a crucial role in this quality. Screening and identification of their related genes are of particular significance. This study identified 21 members of the CaFAD gene family in the C. arabica genome using bioinformatics tools. Gene duplication events observed in the CaFAD gene family were likely driven by natural selection and mutation pressure, with natural selection being more prominent. Transcriptome sequencing, qRT-PCR, and fatty acid profiling across four fruit developmental stages revealed that CaFAD8 was closely associated with fatty acid synthesis regulation. Fatty acid content was initially high but decreased during the later stages, while CaFAD8 expression showed an inverse pattern. Subcellular localization indicated that CaFAD8 functions primarily on the inner membrane. CaFAD8-OE heterologous expression experiment in Arabidopsis thaliana reduced the total fatty acid content in seeds but increased unsaturated fatty acids, including oleic, linoleic, and linolenic acids. These findings suggest that CaFAD8 promotes fatty acid unsaturation and provides insights into fatty acid metabolism in C. arabica. This study offers a foundation for understanding CaFAD gene regulation and supports breeding strategies for high-oil C. arabica varieties.

Genetic strategies can be effective in improving wheat (Triticum aestivum L.) drought stress tolerance, but accumulating evidence suggests that overexpressing drought-resistance genes, especially genes related to the abscisic acid (ABA) signaling pathway, can retard plant growth. We previously characterized the positive roles of the wheat bZIP transcription factor TaFD-Like2-1A (TaFDL2-1A) in drought stress tolerance and ABA biosynthesis and response, whereas a dwarfing shoot exhibited under normal conditions. This study determined the underlying mechanisms that allow TaFDL2-1A to affect shoot growth. Overexpressing TaFDL2-1A decreased cell length, cell width, leaf size, shoot length, and biomass in wheat. The results of RNA-seq showed that multiple differently expressed transcripts are enriched in the auxin signaling pathway. Further analysis indicated higher expression levels of Gretchen Hagen3 (GH3) genes and lower indole-3-acetic acid (IAA) concentrations in the TaFDL2-1A overexpression lines. Exogenous IAA treatment restored the phenotypes of the TaFDL2-1A overexpression lines to wild-type levels. Transcriptional regulation analysis suggested that TaFDL2-1A enhances the expression of auxin metabolism genes, such as TaGH3.2-3A, TaGH3.2-3B, TaGH3.8-2A, and TaGH3.8-2D, by directly binding to ACGT core cis-elements. Furthermore, tafdl2 knockout plants had lower expression levels of these GH3 genes and higher IAA levels than Fielder wheat. These GH3 gene expression and IAA levels were induced and reduced in Fielder wheat and tafdl2 knockout plants treated with exogenous ABA. Our findings elucidate mechanisms underlying the functional redundancy of TaFDL2-1A in the crosstalk between ABA and IAA to affect shoot growth and provide insights into the balance between drought resistance and yield in wheat.

Fusarium pseudograminearum, a soil-borne fungus, is the cause of the devastating wheat disease known as wheat crown rot (WCR). The persistence of this pathogen in the soil and crop residues contributes to the increased occurrence and severity of WCR. Therefore, developing effective strategies to prevent and manage WCR is of great importance. In this study, we isolated a bacterial strain, designated as SR9, from the stem of wheat, that exhibited potent antagonistic effects against F. pseudograminearum, as well as the biocontrol efficacy of SR9 on WCR was quantified at 83.99% ± 0.11%. We identified SR9 as Pseudomonas khavaziana and demonstrated its potential as a plant probiotic. SR9 displayed broad-spectrum antagonism against other fungal pathogens, including Neurospora dictyophora, Botrytis californica, and Botryosphaeria dothidea. Whole-genome sequencing analysis revealed that SR9 harbored genes encoding various cell wall-degrading enzymes, cellulases, and lipases, along with antifungal metabolites, which are responsible for its antagonistic activity. Gene knockout and quantitative PCR analyses reveal that phenazine is the essential factor for antagonism. SR9 possessed genes related to auxin synthesis, flagellar biosynthesis, biofilm adhesion, and the chemotaxis system, which play pivotal roles in plant colonization and growth promotion; we also evaluated the effects of SR9 on plant growth in wheat and Arabidopsis. Our findings strongly suggest that SR9 holds great promise as a biocontrol agent for WCR in sustainable agriculture.IMPORTANCEThe escalating prevalence of wheat crown rot, primarily attributed to Fusarium pseudograminearum, necessitates the development of cost-effective and eco-friendly biocontrol strategies. While plant endophytes are recognized for their biocontrol potential, reports on effective strains targeting wheat crown rot are sparse. This study introduces the Pseudomonas khavaziana SR9 strain as an efficacious antagonist to the wheat crown rot pathogen Fusarium pseudograminearum. Demonstrating a significant reduction in wheat crown rot incidence and notable plant growth promotion, SR9 emerges as a key contributor to plant health and agricultural sustainability. Our study outlines a biological approach to tackle wheat crown rot, establishing a groundwork for innovative sustainable agricultural practices.

TaMYB44-5A identified as a transcription factor negatively regulates drought tolerance in transgenic Arabidopsis. Drought can severely reduce yields throughout the wheat-growing season. Many studies have shown that R2R3-MYB transcription factors are involved in drought stress responses. In this study, the R2R3-MYB transcription factor MYB44-5A was identified in wheat (Triticum aestivum L.) and functionally analyzed. Three homologs of TaMYB44 were isolated, all of which localized to the nucleus. Overexpression of TaMYB44-5A reduced drought tolerance in Arabidopsis thaliana. Further analysis showed that TaMYB44-5A reduced the sensitivity of transgenic Arabidopsis to ABA. Genetic and transcriptional regulation analyses demonstrated that the expression levels of drought- and ABA-responsive genes were downregulated by TaMYB44-5A, and TaMYB44-5A directly bound to the MYB-binding site on the promoter to repress the transcription level of TaRD22-3A. Our results provide insights into a novel molecular pathway in which the R2R3-MYB transcription factor negatively regulates ABA signaling in response to drought stress.

Abstract Background Plant height (PH) and spike compactness (SC) are important agronomic traits that affect yield improvement in wheat crops. The identification of the loci or genes responsible for these traits is thus of great importance for marker-assisted selection in wheat breeding. Results In this study, we used a recombinant inbred line (RIL) population with 139 lines derived from a cross between the mutant Rht8-2 and the local wheat variety NongDa5181 (ND5181) to construct a high-density genetic linkage map by applying the Wheat 40 K Panel. We identified seven stable QTLs for PH (three) and SC (four) in two environments using the RIL population, and found that Rht8-B1 is the causal gene of qPH2B.1 by further genetic mapping, gene cloning and gene editing analyses. Our results also showed that two natural variants from GC to TT in the coding region of Rht8-B1 resulted in an amino acid change from G (ND5181) to V (Rht8-2) at the 175th position, reducing PH by 3.6%~6.2% in the RIL population. Moreover, gene editing analysis suggested that the height of T2 generation in Rht8-B1 edited plants was reduced by 5.6%, and that the impact of Rht8-B1 on PH was significantly lower than Rht8-D1. Additionally, analysis of the distribution of Rht8-B1 in various wheat resources suggested that the Rht8-B1b allele has not been widely utilized in modern wheat breeding. Conclusions The combination of Rht8-B1b with other favorable Rht genes might be an alternative approach for developing lodging-resistant crops. Our study provides important information for marker-assisted selection in wheat breeding.

Salt stress is an abiotic stress factor that limits high yields, and thus identifying salt tolerance genes is very important for improving the tolerance of salt in wheat. In this study we identified 274 TaRING-H2 family members and analyzed their gene positions, gene structures, conserved structural domains, promoter cis-acting elements and covariance relationships. And we investigated TaRING-H2-120 (TaSDIR1) in salt stress. Transgenic lines exhibited higher salt tolerance in the germination and seedling stages. Compared with the wild type, overexpression of TaSDIR1 upregulated the expression of genes encoding enzymes related to the control of reactive oxygen species (ROS), thereby reducing the accumulation of ROS, as well as increased the expression of ion transport-related genes to limit the inward flow of Na+ in vivo and maintain a higher K+/Na+ ratio. The expression levels of these genes were opposite in lines where TaSDIR1 was silenced by BSMV-VIGS, and the silenced wheat exhibited higher salt sensitivity. Arabidopsis mutants and heterologous TaSDIR1 overexpressing lines had similar salt stress tolerance phenotypes. We also demonstrated that TaSDIR1 interacted with TaSDIR1P2 in vivo and in vitro. A sequence of 80-100 amino acids in TaSDIR1P2 encoded a coiled coil domain that was important for the activity of E3 ubiquitin ligase, and it was also the core region for the interaction between TaSDIR1 and TaSDIR1P2. Overall, our results suggest that TaSDIR1 positively regulates salt stress tolerance in wheat.

In order to fully understand the relationship between amylose content, starch physicochemical properties and digestion characteristics of wheat starch, the physicochemical properties and digestion characteristics of starch in four wheat varieties were studied. The results showed that with the increase of amylose content, the setback value increased. At the early stage of starch digestion, the digestion rates of the four starch samples were significantly different, with Xinong 836 being the slowest and Shaannuo 1 being the fastest. The difference was closely related to amylose content and setback value, indicating that amylose tended to retrograde, underwent partial intermolecular rearrangement and recrystallization, and finally reassembleed into ordered aggregates during the cooling process after gelatinization. In addition, this study found that high amylose wheat starch contained more B-type starch granules, but the existence of numerous small starch granules did not result in the increase of starch digestion rate and the overall degree of digestion, indicating that particle size did not change the starch digestibility after starch gelatinizing adequately.

为探讨不同类型小麦品种面筋品质形成的机制,以面筋强度不同的西农20、西农836、周麦18和西农977为材料,比较分析其面筋结构特性、籽粒灌浆过程蛋白组分积累动态、氮代谢和贮藏蛋白合成相关基因表达的差异,并从生理水平和转录水平探究氮代谢和贮藏蛋白生物合成相关基因表达对小麦面筋品质形成的影响.结果表明,西农20的面团形成时间、稳定时间、蛋白质弱化度最高,其次是西农836、周麦18、西农977;西农20的面筋中二硫键和β-折叠含量最高,而表面疏水性和α-螺旋/β-折叠最低,表现为面筋微观网络交联更加致密;籽粒灌浆期间醇溶蛋白、谷蛋白、谷蛋白大聚体(GMP)快速积累,成熟期西农20籽粒中总蛋白质、醇溶蛋白、谷蛋白及GMP含量比其他三个品种都高;旗叶和籽粒中谷氨酰胺合成酶(GS)和谷丙转氨酶(GPT)活性及其基因表达水平在西农20中最高,从而加强了其旗叶和籽粒中氨基酸代谢;贮藏蛋白合成相关基因x/y-HMW、LMW-A/B/D、TaGAMyb、TaPBF、TaSPA、TaPDIL2-1、TaSUMO1 和 TaPPIase 的表达水平也在西农20中最高.这说明小麦籽粒灌浆期间氮代谢和贮藏蛋白生物合成相关基因的高水平表达可促进籽粒贮藏蛋白的合成与聚集,从而提高小麦面筋的品质.

Ethylene has an important role in regulating plant growth and development as well as responding to adversity stresses. The 1-aminocyclopropane-1-carboxylate synthase (ACS) is the rate-limiting enzyme for ethylene biosynthesis. However, the role of the ACS gene family in wheat has not been examined. In this study, we identified 12 ACS members in wheat. According to their position on the chromosome, we named them TaACS1-TaACS12, which were divided into four subfamilies, and members of the same subfamilies had similar gene structures and protein-conserved motifs. Evolutionary analysis showed that fragment replication was the main reason for the expansion of the TaACS gene family. The spatiotemporal expression specificity showed that most of the members had the highest expression in roots, and all ACS genes contained W box elements that were related to root development, which suggested that the ACS gene family might play an important role in root development. The results of the gene expression profile analysis under stress showed that ACS members could respond to a variety of stresses. Protein interaction prediction showed that there were four types of proteins that could interact with TaACS. We also obtained the targeting relationship between TaACS family members and miRNA. These results provided valuable information for determining the function of the wheat ACS gene, especially under stress.

Drought is a deleterious abiotic stress factor that constrains crop growth and development. Post-translational modification of proteins mediated by the ubiquitin-proteasome system is an effective strategy for directing plant responses to stress, but the regulatory mechanisms in wheat remain unclear. In this study, we showed that TaSDIR1-4A is a positive modulator of the drought response. Overexpression of TaSDIR1-4A increased the hypersensitivity of stomata, root length and endogenous abscisic acid (ABA) content under drought conditions. TaSDIR1-4A encodes a C3H2C3-type RING finger protein with E3 ligase activity. Amino acid mutation in its conserved domain led to loss of activity and altered the subcellular localization. The membrane-bound transcription factor TaWRKY29 was identified by yeast two-hybrid screening, and it was confirmed as interacting with TaSDIR1-4A both in vivo and in vitro. TaSDIR1-4A mediated the polyubiquitination and proteolysis of the C-terminal amino acid of TaWRKY29, and its translocation from the plasma membrane to the nucleus. Activated TaWRKY29 bound to the TaABI5 promoter to stimulate its expression, thereby positively regulating the ABA signalling pathway and drought response. Our findings demonstrate the positive role of TaSDIR1-4A in drought tolerance and provide new insights into the involvement of UPS in the wheat stress response.

The discovery and identification of gene families by using wide-genome and public databases is an effective way to gain initial insight into gene function, which also is one of the current hot spots of research. Chlorophyll abbinding proteins (LHC) are important for photosynthesis and widely involved in plant adversity stress. However, the study in wheat has not been reported. In this study, we identified 127 TaLHC members from common wheat which were unevenly distributed on all chromosomes except 3B and 3D. All members divided into three subfamilies, LHC a, LHC b and the LHC t which was only discovered in wheat. All of them had maximum expression in leaves and contained multiple light-responsive cis-acting element, which were evidence of the extensive involvement of LHC families in photosynthesis. In addition, we also analyzed their collinear relationship, targeting relationship with miRNA and their responses under different stresses. Based on these analyses, it was found that TaLHC86 was an excellent candidate gene for stress resistance. The full-length ORF of TaLHC86 was 792 bp and was localized on the chloroplasts. The salt tolerance of wheat was reduced when BSMV-VIGS silenced TaLHC86, and the photosynthetic rate and electron transport were also seriously affected. This study made a comprehensive analysis of the TaLHC family and found that TaLHC86 was a good gene for salt tolerance.

Low temperature and cold damage are natural factors that seriously reduce wheat yield. Thus, how to improve the cold resistance of wheat has been the focus of wheat breeders and geneticists. However, the genetic improvement for this trait has been slow, mainly because cold resistance is a complex quantitative trait and field phenotypic identification is relatively difficult. Therefore, the discovery, mapping, and cloning of the cold resistance genes of wheat provide a theoretical basis for the genetic improvement of wheat against cold resistance and facilitate the analysis of the molecular mechanisms of cold resistance in wheat. This study used the wheat line H261 and its EMS mutants LF2099 and XiNong 239 as materials. Cold trait segregation occurred in the F 2 generation of mutants LF2099 and XiNong 239 at a 15:1 separation ratio. Genetic analysis showed that two dominant overlapping genes, temporarily named Wcr-3 and Wcr-4 , control cold resistance in wheat. Furthermore, a combined BSA and SNP array established that Wcr-3 is between BU100519 (SSR marker) and AX-94843669 (SNP marker). The markers are 1.32 cM apart, corresponding to the 5.41 Mb physical interval on the Chinese Spring 2B chromosome with 67 functionally annotated genes. Wcr-4 is located between AX-94657955 (SNP marker) and LC-23 (SSR marker), which are 1.79 cM apart, corresponding to a 2.35 Mb physical interval on the Chinese Spring 2D chromosome, which contains 66 functionally annotated genes. Wcr-3 and Wcr-4 are two new cold resistance genes, laying the foundation for their fine mapping and cloning.

Background Wheat flour maturation affects the aggregation and structural stability of proteins. The number of high-molecular-weight glutenin subunits (HMW-GSs) differs in various wheat varieties. The effects of Dx2 absence on the protein aggregation characteristics and thermal stability of flour were investigated during 120 d of maturation using near-isogenic lines (NILs). Results The absence of Dx2 delayed and decreased the protein aggregation of flours during maturation, i.e. the maturation-induced increases were later and smaller for glutenin, glutenin macropolymer (GMP), glutenin/gliadin ratio, beta-sheets, and beta-sheet/alpha-helix ratio in HMW-D1a without Dx2 than in HMW-D1p with Dx2; these differences were ascribed to the weaker interactions between the sulfhydryl (-SH) groups, disulfide bonds (-S-S-), and hydrophobicity in the flours without Dx2. Flour maturation caused the dough microstructures to be more compact and denser, thereby increasing the flour thermal stability as observed by a higher denaturation peak temperature (T-p), enthalpy of thermal transition (Delta H), and degradation temperature (T-d), These changes led to better dough properties such as dough development time, dough stability time, and protein weakening, but the optimal stage in HMW-D1a without Dx2 was reached later. Conclusion These findings deepen the understanding of how HMW-GS Dx2 modifies protein structures during flour maturation.

High amylose wheat (HAW) has potential health benefits but its dough structure is usually inferior. Wheat dough is a complex mixture and its structure is influenced by the physicochemical properties of gluten and starch. In this study, we investigated the starch granule development, gluten structure, starch properties, pasting, and thermal properties of flour, as well as the rheological properties of dough in wheat variety Xinong 836 with high amylose content (33.57%) and its parents. The results showed that Xinong 836 wheat starch contained more small starch granules, which was consistent with the microstructural results of starch granules in grain filling stage. Moreover, Xinong 836 wheat starch showed highest swelling power and water solubility. Importantly, the flour of Xinong 836 wheat had the highest protein content and wet gluten content and Xinong 836 wheat gluten showed highest β-sheets content and disulfide bond content than its parents Zhengmai 7698 and Xinong 979, which conferring to more compact microscopic networks of dough, thereby contributing to the higher peak viscosity (PV), final viscosity (FV), and setback viscosity (SB) in the flour of Xinong 836. Our finding elucidated that the stability of gluten and properties of starch synergistically affected the pasting and thermal properties of the flour paste, and the presence of more small starch granules contributed to dough with a rather dense structure in HAW Xinong 836. Thus, superior gluten structure and more small starch granules have synergistic effects on enhancing the gluten–starch interaction, thereby contributing to better dough quality.

Dear Editor, Wheat(Triticum aestivum)is a major staple crop in the world and provides～20％of the food calories for human consumption(Appels et al.,2018).During the 1960s and 1970s,the introduction of two semi-dwarfing genes Rht-B1b and Rht-D1b in wheat varieties strikingly improved lodging resistance and har-vest index,and therefore substantially increased grain yield,re-sulting in the well-known"Green Revolution"(Peng et al.,1999).

TaGW2 has been identified as a key determinant of the grain weight in wheat (Triticum aestivum L.). In our previous study, we found that the grain size differs in Chinese Spring (CS) and its TaGW2-6A allelic variant (NIL31). In addition, the expression of the key starch biosynthesis enzyme gene TaAGPS differs significantly in the two materials. However, the underlying molecular mechanism associated with the action of TaGW2-6A has not been reported. In the present study, we found that TaGW2-6A-CS interacted with TaAGPS, whereas TaGW2-6A-NIL31 did not interact with it in vitro and in vivo. Furthermore, we found that the C-terminal LXLX domain (376-424 aa) of TaGW2-6A recognized TaAGPS. However, the TaGW2-6A allelic variant lacked this key interaction region due to premature translation termination. We also found that TaGW2-6A-CS can ubiquitinate TaAGPS and degrade it via the 26 S proteasome pathway. In addition, our analysis of the activity of ADP-glucose pyrophosphorylase (AGPase) indicated that the AGPase level in the endosperm cells was lower in CS than NIL31. Cytological observations demonstrated that the average number of starch granules and the average area of starch granules in endosperm cells were lower in CS than NIL31. The overexpression of TaAGPS positively regulated the seed size in transgenic Arabidopsis. Our findings provide novel insights into the molecular mechanism that allows TaGW2-6A-TaAGPS to regulate seed size via the starch synthesis pathway.

宛麦1326是南阳市农业科学院和西北农林科技大学农学院2009年以宛110160为母本、开麦21为父本杂交,通过系谱法选育而成的小麦新品种.其于2021年通过河南省农作物品种审定委员会审定,审定编号豫审麦20210024.