Ali Haider, McDonald Megan C, Kettles Graeme J
School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
Mol Plant Microbe Interact. 2025 Mar;38(2):226-234. doi: 10.1094/MPMI-08-24-0082-TA. Epub 2025 Jan 24.
Septoria tritici blotch is caused by the fungus and poses a major threat to wheat productivity. There are over 20 mapped loci in wheat that confer strong (gene-for-gene) resistance against this pathogen, but the corresponding genes in that confer virulence against distinct genes remain largely unknown. In this study, we developed a rapid forward genetics methodology to identify genes that enable to gain virulence on previously resistant wheat varieties. We used the known gene-for-gene interaction between and as a proof of concept that this method could quickly recover single candidate virulence genes. We subjected the avirulent strain IPO323, which carries the recognized allele, to ultraviolet (UV) mutagenesis and generated a library of over 66,000 surviving spores. We screened these survivors on leaves of the resistant wheat variety Cadenza in mixtures (soups) ranging from 100 to 500 survivors per soup. We identified five soups with a gain-of-virulence (GoV) phenotype relative to the IPO323 parental strain and re-sequenced 18 individual isolates, including four control isolates and two isolates lacking virulence, when screened individually. Of the 12 confirmed GoV isolates, one had a single nucleotide polymorphism (SNP) in the coding region. The other 11 GoV isolates exhibited large (approximately 70 kb) deletions at the end of chromosome 5, including the locus. Our findings demonstrate the efficiency of this forward genetic approach in elucidating the genetic basis of qualitative resistance to and the potential to rapidly identify other, currently unknown, genes in this pathogen. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
小麦黄斑叶枯病由真菌引起，对小麦生产力构成重大威胁。小麦中有超过20个定位位点赋予对该病原体的强（基因对基因）抗性，但该真菌中针对不同小麦抗性基因赋予毒力的相应基因仍 largely unknown。在本研究中，我们开发了一种快速正向遗传学方法来鉴定使该真菌能够在先前抗性小麦品种上获得毒力的基因。我们利用该真菌与小麦之间已知的基因对基因相互作用作为概念验证，证明该方法可以快速恢复单个候选毒力基因。我们对携带已识别的avr等位基因的无毒力菌株IPO323进行紫外线诱变，生成了一个超过66,000个存活孢子的文库。我们在抗性小麦品种卡丹扎的叶片上以每“汤”100至500个存活孢子的混合物（“汤”）形式筛选这些存活者。我们鉴定出相对于IPO323亲本菌株具有毒力获得（GoV）表型的五个“汤”，并对18个单独分离株进行了重测序，包括四个对照分离株和两个单独筛选时缺乏毒力的分离株。在12个已确认的GoV分离株中，一个在avr编码区域有一个单核苷酸多态性（SNP）。其他11个GoV分离株在5号染色体末端表现出大的（约70 kb）缺失，包括avr位点。我们的研究结果证明了这种正向遗传方法在阐明对该真菌定性抗性的遗传基础方面的效率，以及快速鉴定该病原体中其他目前未知的avr基因的潜力。[公式：见正文] 版权所有© 2025作者。这是一篇根据CC BY - NC - ND 4.0国际许可分发的开放获取文章。
