Askarian Homa, Akhavan Alireza, González Leonardo Galindo, Hwang Sheau-Fang, Strelkov Stephen E
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
Plant Dis. 2021 Nov;105(11):3694-3704. doi: 10.1094/PDIS-09-20-1980-RE. Epub 2021 Nov 18.
Clubroot, caused by Woronin, is a significant threat to the canola ( L.) industry in Canada. Clubroot resistance has been overcome in more than 200 fields since 2013, representing one of the biggest challenges to sustainable canola production. The genetic structure of 36 single-spore isolates derived from 12 field isolates of collected before and after the introduction of clubroot resistant (CR) canola cultivars (2005-2014) was evaluated by simple sequence repeat (SSR) marker analysis. Polymorphisms were detected in 32 loci with the identification of 93 distinct alleles. A low level of genetic diversity was found among the single-spore isolates. Haploid linkage disequilibrium and number of migrants suggested that recombination and migration were rare or almost absent in the tested population. A relatively clear relationship was found between the genetic structure and virulence phenotypes of the pathogen as defined on the differential hosts of Somé et al., Williams, and the Canadian Clubroot Differential (CCD) set. Although genetic variability within each pathotype group, as classified on each differential system, was low, significant genetic differentiation was observed among the pathotypes. The highest correlation between genetic structure and virulence was found among matrices produced with genetic data and the hosts of the CCD set, with a threshold index of disease of 50% to distinguish susceptible from resistant reactions. Genetically homogeneous single-spore isolates provided a more complete and clearer picture of the population genetic structure of , and the results suggest some promise for the development of pathotype-specific primers.
由沃罗宁菌引起的根肿病对加拿大的油菜籽（油菜）产业构成重大威胁。自2013年以来，200多个田地的根肿病抗性已被克服，这是油菜籽可持续生产面临的最大挑战之一。通过简单序列重复（SSR）标记分析，对2005 - 2014年引入抗根肿病（CR）油菜品种前后收集的12个田间分离株衍生的36个单孢子分离株的遗传结构进行了评估。在32个位点检测到多态性，鉴定出93个不同的等位基因。在单孢子分离株中发现遗传多样性水平较低。单倍体连锁不平衡和迁移数量表明，在测试的病原菌群体中重组和迁移很少或几乎不存在。在根据索梅等人、威廉姆斯的鉴别寄主以及加拿大根肿病鉴别集（CCD）定义的病原菌遗传结构和毒力表型之间发现了相对明确的关系。尽管在每个鉴别系统分类的每个致病型组内遗传变异性较低，但在致病型之间观察到显著的遗传分化。在利用遗传数据生成的矩阵与CCD集的寄主之间，发现遗传结构与毒力之间的相关性最高，疾病阈值指数为50%，以区分敏感反应和抗性反应。遗传同质的单孢子分离株为病原菌群体遗传结构提供了更完整、更清晰的图景，结果表明开发致病型特异性引物有一定前景。
