Theoretical and Applied Genetics最新文献

{"title":"Genome-wide characterisation of leaf rust resistance loci in an Eastern European barley collection.","authors":"Shiva Azizinia, Md Arifuzzaman, Eden Tongson, Karanjeet Sandhu, Gabriel Keeble-Gagnère, Ghazanfar Abbas Khan, Kerrie Forrest, Matthew Hayden, Dragan Perovic, Davinder Singh, Peter M Dracatos","doi":"10.1007/s00122-026-05405-4","DOIUrl":"10.1007/s00122-026-05405-4","url":null,"abstract":"<p><strong>Key message: </strong>GWAS and inheritance testing uncovered known and potentially new genetic sources of leaf rust resistance in barley, mapping the dominant locus RphCaspian (RphCas) to chromosome 4HL in close physical proximity to Rph21. This study has unravelled the genetic architecture of leaf rust in barley and also provides closely linked SNP markers on the 40k Infinium wheat barley array suitable for marker assisted selection. Barley leaf rust (BLR) is a damaging foliar disease affecting grain yield and quality. Genetic resistance offers a sustainable solution, but often succumbs to breakdown in the absence of stewardship. Sourcing and incorporating novel diverse alleles in breeding programs is challenging yet enhanced by mining unexplored gene pools available in gene banks. In this study, we investigated 318 barley accessions of Eastern European origin for BLR resistance using detailed greenhouse-based host-pathogen interaction assays at the seedling stage. The panel was genotyped using two marker platforms, targeted genotyping-by-sequencing and Infinium™ Wheat Barley 40 K BeadChip Array. Following marker curation, 35,059 SNPs were used for genome-wide association studies (GWAS) using GAPIT/FarmCPU, with associated regions further supported using a BayesR approach. GWAS identified significant peaks corresponding to known resistance loci, including Rph2, Rph3 and Rph12, as well as potentially uncharacterised BLR resistance QTL on chromosomes 1HL, 2HL, 3HS and 6HS. Several biparental populations were also developed by crossing three diverse EEB donors carrying broadly effective BLR resistance including: Caspian, Anska and Athenais, with the leaf rust-susceptible barley cultivar Gus. Genetic analysis at the F₃ generation revealed that resistance Athenais was consistent with two-gene inheritance, whereas resistance in Caspian was controlled by a single dominant gene (RphCas) and the inheritance of resistance in Anska was inconclusive. Bulked segregant RNA sequencing and conventional bulked segregant analysis (BSA) mapped the Caspian resistance locus to chromosome 4HL. An allelism test using an F₃ population derived from Riccardo, carrying Rph21, and Caspian, tested with a Puccinia hordei pathotype (5457P+) avirulent to both resistance sources, susggested that the RphCas locus was distinct from Rph21 however their close physical proximity and haplotypic similarity requires further investigation for a formal gene designation for RphCas.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13676509/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149216758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genome-wide association study and transcriptome analysis reveal candidate genes associated with mesosulfuron-methyl tolerance in wheat.","authors":"Jie Zhao, Minghao Cai, Lijing Sun, Mengyun Hu, Hui Li, Xiaomin Liu, Yingjun Zhang","doi":"10.1007/s00122-026-05411-6","DOIUrl":"https://doi.org/10.1007/s00122-026-05411-6","url":null,"abstract":"<p><strong>Key message: </strong>This study identified and validated stable genetic loci associated with MSM tolerance, predicted the underlying candidate genes, and provided marker-assisted selection tools for improving wheat herbicide tolerance. Mesosulfuron-methyl (MSM) is one of the few herbicides conferring high efficacy in eliminating poaceae weeds. Improper application, however, can result in phytotoxicity and yield reduction in wheat. Cultivating herbicide-tolerant wheat varieties is therefore of significant agricultural importance, though the genetic basis of this tolerance remains poorly understood. This study performed a genome-wide association study (GWAS) on 539 wheat accessions to explore the genetic foundation of MSM tolerance. Four stable genetic loci associated with MSM tolerance, designated as QMSL-3D.1, QMSL-4A.1, QMSL-5A.1/QMSH-5A.1, and QMSL-5B.1, were identified on chromosomes 3D, 4A, 5A, and 5B, respectively. Pyramiding superior alleles of these loci reduced the mean herbicide damage rating (HDR) by 32.1% and 26.6% under the two tested MSM dosages, respectively, though these alleles collectively explained a minor proportion of the phenotypic variation. Transcriptomic comparison between the MSM-tolerant cultivar Chang 4640 and susceptible cultivar Xinong 928 under MSM treatment identified two differentially expressed candidate genes, TraesCS5A02G398300 and TraesCS5B02G403400. These two homoeologous genes encoded aspartate-semialdehyde dehydrogenase, a key enzyme involved in the biosynthesis of essential amino acids. Furthermore, six Kompetitive Allele-Specific PCR (KASP) markers closely linked to the identified tolerance loci and candidate genes were developed. Field evaluation across multiple years and MSM concentrations screened out five wheat varieties with stable MSM tolerance. Collectively, this study identifies valuable genetic loci and molecular markers for wheat MSM tolerance, provides preliminary transcriptomic insights into herbicide response, and offers a useful resource for subsequent tolerance gene validation and wheat molecular breeding.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149207986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multi-omic dissection of spatial hierarchy-dependent grain development in barley (Hordeum vulgare L.).","authors":"Yi Hong, Huichao Wu, Xupeng Su, Juan Zhu, Chao Lv, Baojian Guo, Feifei Wang, Luobu Zhaxi, Rugen Xu","doi":"10.1007/s00122-026-05414-3","DOIUrl":"https://doi.org/10.1007/s00122-026-05414-3","url":null,"abstract":"<p><strong>Key message: </strong>GWAS on grain uniformity and transcriptomics across spike shapes/positions reveal checkpoints in barley grainheterogeneity development. Grain uniformity, defined as the consistency of grain size among siblings within a sample, can influence yield performance and malting quality in barley, yet its genetic basis remains poorly understood. Here, we combine genome-wide association analysis of 334 barley accessions with spatiotemporal transcriptomics of two cultivars exhibiting contrasting uniformity. We identified six quantitative trait loci (QTLs) across chromosomes 1H, 2H, 4H, and 5H. The non-uniform cultivar displayed 3,314 differentially expressed genes between apical and basal grains at grain filling stage, versus only 222 in the uniform cultivar. This approximately 15-fold difference was accompanied by positional differences in starch biosynthesis, sugar transport, and trehalose-6-phosphate signaling. We identified four candidate genes proximal to stable GWAS signals on chromosome 1H and developed a dCAPS marker. These findings identify grain filling stage as a key stage associated with grain uniformity and suggest asymmetric carbon metabolism as a candidate mechanism underlying spatial hierarchy-dependent grain development.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149184451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leaf variegation in a barley EMS mutant is controlled by two epistatic mutations.","authors":"Hélène Pidon, Shobhashree Rajulareddy Nagireddy, Michael Melzer, Axel Himmelbach, Nils Stein","doi":"10.1007/s00122-026-05370-y","DOIUrl":"10.1007/s00122-026-05370-y","url":null,"abstract":"<p><strong>Key message: </strong>We identified digenic control of leaf variegation in a barley mutant. Candidate genes, identified through whole-genome resequencing, are consistent with possible roles in chloroplast proteostasis. Variegation mutants provide valuable insights into chloroplast biogenesis. We characterized a newly identified variegated barley mutant, in which the phenotype is controlled by two epistatic recessive genes. The causal loci, var4 and var5, were mapped on chromosomes 2H and 3H. We used genotyping-by-sequencing, linkage mapping, and PACE genotyping, followed by whole-genome resequencing to identify candidate genes. Our two top candidate genes are an NBR1-like selective autophagy receptor gene and a DNAJ-domain-containing gene, respectively. Based on their homology-based functional annotation, both candidates could be implicated in chloroplast proteostasis, regulating protein import, folding, and/or degradation. While functional confirmation is still required, mild, independent defects in proteostasis from each mutation may act synergistically to surpass a functional threshold, impairing chloroplast development in early leaves while allowing partial recovery in later stages. These findings reveal a novel digenic basis for variegation in barley and identify candidate genes and pathways linked to chloroplast proteostasis.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13668966/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149184276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two independent dominant resistance genes confer resistance to spot blotch in wheat.","authors":"Beibei Li, Jingzhong Xie, Guanghao Guo, Panpan Zhang, Huaizhi Zhang, Keyu Zhu, Baoge Huang, Qiuhong Wu, Yongxing Chen, Chengguo Yuan, Lingli Dong, Zhiyong Liu, Ping Lu","doi":"10.1007/s00122-026-05412-5","DOIUrl":"https://doi.org/10.1007/s00122-026-05412-5","url":null,"abstract":"<p><p>Bipolaris sorokiniana-induced spot blotch constitutes a major wheat disease in warm, humid production regions globally. Elucidating its genetic control is essential for breeding cultivars that mitigate yield and quality losses. We evaluated F₂ and F_2:3 generations from a WE35 × S2199 cross for resistance phenotypes. Genetic analysis revealed that resistance was controlled by two independent dominant genes: the previously identified Sb3 and a novel resistance gene designated SbWE35. Bulked segregant RNA-Seq (BSR-Seq) analysis using a segregating population from a cross between WE35 and a spot blotch susceptible line 621-18-3 mapped SbWE35 to chromosome 4BL. Fine mapping delimited SbWE35 to a 0.07 cM interval between markers YK12918 and YK13104 corresponding to 1.08 Mb in the Chinese Spring reference genome. Comparative genetic mapping revealed substantial overlap between the SbWE35 and Sb4 intervals, suggesting that SbWE35 and Sb4 may represent the same genetic locus, although formal allelism tests are required for confirmation. KEY MESSAGE : We identifiedSbWE35, a wheat spot blotch resistance gene, and demonstrated that resistance to spot blotch is controlled by two independent dominant genes,Sb3andSbWE35.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149184250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genome-wide association mapping of tan spot resistance in a modified NAM population derived from synthetic hexaploid wheat.","authors":"Anil Karmacharya, Dhondup Lhamo, Md Mukul Islam, Han-Chang Chang, Jason D Fiedler, Timothy L Friesen, Justin D Faris, Shengming Yang, Xiaofei Zhang, Yong Q Gu, Zhaohui Liu, Steven S Xu","doi":"10.1007/s00122-026-05382-8","DOIUrl":"https://doi.org/10.1007/s00122-026-05382-8","url":null,"abstract":"<p><strong>Key message: </strong>A total of 37 SNPs associated with resistance to five races of Pyrenophora tritici-repentis and two necrotrophic effectors were identified in a NAM population derived from synthetic and spring wheat. Tan spot, caused by Pyrenophora tritici-repentis, is a major foliar disease of wheat worldwide, and expanding the genetic basis of resistance remains a breeding priority. Synthetic hexaploid wheat (SHW) represents a valuable reservoir of novel alleles, yet its contribution to tan spot resistance has not been fully characterized. Here, a modified Nested Association Mapping population including 276 BC₁F₈ lines from crosses between four SHW parents and diverse hard red spring wheat (HRSW) cultivars was evaluated for reactions to five P. tritici-repentis races and two associated necrotrophic effectors (NEs) (Ptr ToxA and Ptr ToxB). The population exhibited broad phenotypic variation, with SHW parents and 66 BC₁F₈ lines showing resistance to all races. Genome-wide association analysis identified 21 marker-trait associations (MTAs) associated with tan spot resistance, of which, 6 resistance alleles were derived from SHW and 4 from HRSW parents, and 11 from both. Major-effect resistance loci were localized on chromosomes 5A, 2B, 5B, and 7D. Additionally, 14 MTAs were associated with Ptr ToxA sensitivity and 2 with Ptr ToxB sensitivity. Resistance alleles contributed by both parents showed a significant additive effect in reducing disease severity. Several loci colocalized with previously reported QTLs or genes, including Tsn1-B1 and Tsc2, while others represent potentially novel genomic regions. Notably, multiple lines were resistant to all races despite sensitivity to one or both NEs, indicating the presence of quantitative resistance other than those effector-sensitivity loci. These findings provide valuable genetic resources for facilitating marker‑assisted and genomic selection targeting tan spot resistance in wheat breeding.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149184012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TaSTG4B enhances wheat salt tolerance via regulation of antioxidant and photosynthetic protection pathways.","authors":"Min Xue, Yingying Sun, Ruiyang Sun, Dewei Kong, Xingshu Zhang, Yuanfang Jin, Xiang Li, Haixia Yu, Weidong Zhang, Piyi Xing, Jingjuan Zhang, Qi'er Liu, Jiansheng Chen","doi":"10.1007/s00122-026-05403-6","DOIUrl":"10.1007/s00122-026-05403-6","url":null,"abstract":"<p><p>Soil salinization represents a major abiotic stress constraining wheat yield. Identifying key salt tolerance-related genes and unraveling their regulatory mechanisms is critical for breeding salt-tolerant wheat varieties. In this study, TaSTG4B (Triticum aestivum Salt-Tolerant Gene on 4B, gene ID: TraesCS4B02G042300), a key regulatory gene encoding an oxysterol-binding protein homolog, was jointly identified by ethyl methanesulfonate (EMS)-induced mutagenesis screening and genome-wide association study (GWAS), and systematically elucidated its salt tolerance mechanisms. TaSTG4B exhibits relatively higher expression in wheat roots, suggesting that it primarily functions in this organ. Under 200 mM NaCl treatment (simulating moderate salt stress in saline-alkali soils), TaSTG4B overexpression (OE) lines exhibited significantly greater shoot and root biomass, and elevated activities of antioxidant enzymes compared to the wild type (Fielder). In contrast, TaSTG4B knockout (KO) lines showed markedly reduced salt tolerance. Physiological analysis revealed that TaSTG4B overexpression enhances wheat's antioxidant capacity, maintains ion homeostasis, and mitigates membrane damage under salt stress. RNA sequencing (RNA-seq) analysis revealed that under non-stress conditions, TaSTG4B primarily regulates pathways such as secondary metabolite biosynthesis-including key salt-stress-related pathways like proline (PRO), polyamine, and flavonoid biosynthesis-as well as glutathione metabolism, collectively establishing a \"primed state of defense.\" Under salt stress, it activates glutathione metabolism, photosynthesis-antenna proteins, and ion homeostasis pathways, coordinating antioxidant defense and photosynthetic protection. This study demonstrates that TaSTG4B enhances wheat salt tolerance through a hierarchical regulatory mode of pre-adaptation and stress-specific induction, providing valuable genetic resources and a theoretical basis for the breeding of salt-tolerant wheat varieties.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149184260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unlocking the future of crop improvement with crop wild relatives.","authors":"Ruixue Xiao, Xiaopeng Li","doi":"10.1007/s00122-026-05399-z","DOIUrl":"10.1007/s00122-026-05399-z","url":null,"abstract":"<p><p>Crop wild relatives (CWRs) retain extensive genetic diversity lost during crop domestication, yet their translation into breeding outcomes remains constrained by fundamental quantitative-genetic and population-genetic bottlenecks. Here, we propose an integrative framework that evaluates CWR deployment through three interconnected genetic lenses: (i) the architecture of domestication bottlenecks and their consequences for allelic diversity, linkage disequilibrium, and selectable genetic variation in modern breeding pools; (ii) the genetic determinants of successful allele transfer, distinguishing between loci with stable, reproducible breeding effects and those confined to proof-of-concept discovery; and (iii) the population-genetic limitations of emerging biotechnologies -- including pan-genome resolution, genome-editing precision, genomic-selection prediction accuracy, and de novo domestication scalability -- when applied to wild genetic backgrounds. By synthesizing population-genetic theory with empirical case studies across cereals, legumes, and Solanaceous crops, we identify critical translational gaps between genomic discovery and cultivar release, and outline testable genetic hypotheses to guide future CWR-based breeding. This review advances the field by shifting the discourse from technological potential to quantitative-genetic realism, providing breeders and geneticists with a mechanistic roadmap for prioritizing CWR resources.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149184222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined linkage mapping and association analysis reveal the genetic control of starch content in maize kernel.","authors":"Langlang Ma, Hengshuo Chang, Yun Liu, Wei Min, Hui Hu, Xin Zhang, Wei Dai, Zhong Chen, Chaoying Zou, Thomas Lübberstedt, Yaou Shen","doi":"10.1007/s00122-026-05402-7","DOIUrl":"10.1007/s00122-026-05402-7","url":null,"abstract":"<p><p>Starch is a major component of kernel weight that strongly affects maize yield, yet the genetic regulation of starch content in maize kernel is not fully elucidated. Here, we carried out a linkage mapping for starch content using an IBM Syn10 DH population derived from B73 and Mo17, which comprises 222 inbred lines with 6618 bin markers, evaluated across four environments. A total of 13 quantitative trait loci were detected, among which five were simultaneously identified across multiple environments. By integrating the gene-based association analyses, we identified the candidate gene Zm00001d039265 that encodes β-amylase 4, a potential modulator underlying leaf starch degradation. Gene-based association analysis was performed using a natural panel including 285 germplasms collected from the breeding program of Southwest China. The variant SNP-3-826178 residing in 3'-UTR of Zm00001d039265 was significantly associated with kernel starch content, which categorized these germplasms into two genotypes (high starch content: allele C; low starch content: allele T). We further validated this allelic effect in an independent recombinant inbred line population containing 248 inbred lines derived from A188 and B73, confirming that lines carrying the C allele possessed significantly higher kernel starch accumulation than those harboring the T allele. Finally, we developed a derived cleaved amplified polymorphic sequence marker targeting SNP-3-826178, which was able to distinguish T allele and C allele among the inbred lines with different backgrounds. Our findings deepen the understanding of the genetic basis governing maize kernel starch formation and provide an available molecular marker for identifying germplasms with high starch content in maize breeding.Key Message Gene Zm00001d039265 underlying starch content was excavated by linkage mapping and gene-based association analysis. According to the SNP-3-826178 within Zm00001d039265, a dCAPS marker was successfully developed.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149184505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fine mapping of QPm.caas-4BL.2 for adult-plant resistance to powdery mildew in wheat.","authors":"Yan Dong, Yachao Dong, Xiaowan Xu, Yan Ren, Jindong Liu, Dengan Xu, Yuanfeng Hao, Yuxin Yang, Weijun Zhang, Ling Kang, Jinshang He, Lina Cao, Nana Ren, Xueyong Zhang, Zhonghu He, Xianchun Xia, Dongsheng Chen","doi":"10.1007/s00122-026-05406-3","DOIUrl":"10.1007/s00122-026-05406-3","url":null,"abstract":"<p><strong>Key message: </strong>We fine-mapped QPm.caas-4BL.2 for adult-plant resistance to powdery mildew in an 880-kb physical interval, predicted a candidate gene, identified a favorable haplotype in wheat, and developed a CAPS marker for marker-assisted breeding. Powdery mildew, a globally devastating disease, severely impairs both grain yield and quality in wheat. Identification of powdery mildew resistance genes is essential for marker-assisted selection of disease-resistant wheat cultivars. In the present study, we conducted fine mapping of the QTL QPm.caas-4BL.2 for adult-plant resistance to powdery mildew from the Zhou8425B/Chinese Spring recombinant inbred line (RIL) population. By integrating genotypic and phenotypic data from progeny populations of 63 heterozygous recombinant individuals, QPm.caas-4BL.2 was mapped to an 880-kb physical interval (611.71-612.59 Mb) on chromosome 4B, containing 12 high-confidence annotated genes in the Chinese Spring reference genome (IWGSC RefSeq v2.1). TraesCS4B03G0836900 (annotated as an MLO) was considered a potential causal gene of QPm.caas-4BL.2 based on gene sequence polymorphisms, transcriptome profiles, and haplotype analysis. The TraesCS4B03G0836900 gene contains seven SNPs (single nucleotide polymorphisms) and formed six haplotypes in 145 re-sequenced wheat accessions, with Hap5-mlo carrying a missense mutation that showed significantly lower disease severity than other haplotypes. A cleaved amplified polymorphic sequence (CAPS) marker targeting the missense mutation was developed and validated in the Zhou8425B-derived varieties. Varieties carrying Zhou8425B allele exhibited 6.9% reduction in disease severity compared to those with Chinese Spring allele. This study provides genes, molecular markers, and resistant germplasm for improvement of powdery mildew resistance in wheat cultivars.</p>","PeriodicalId":22955,"journal":{"name":"Theoretical and Applied Genetics","volume":"139 11","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149183727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}