Zou Zhongwei, Liu Fei, Selin Carrie, Fernando W G Dilantha
Department of Plant Science, University of Manitoba, Winnipeg, MB, Canada.
Front Microbiol. 2020 Aug 11;11:1969. doi: 10.3389/fmicb.2020.01969. eCollection 2020.
Blackleg, caused by the fungal pathogen , is the most important disease affecting canola () crops worldwide. We employed the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) system to generate the mutant isolate umavr7 from a point mutation of the coding region in a isolate (UMAvr7). Reverse transcription PCR and transcriptome data confirmed that the gene was knocked out in the mutant isolate. Pathogenicity tests indicated that umavr7 can cause large lesions on a set of differential genotypes that express different resistance () genes. Comparative pathogenicity tests between UMAvr7 (wild type) and umavr7 on the corresponding genotype 01-23-2-1 (with ) showed that umavr7 is a mutant isolate, producing large gray/green lesions on cotyledons. The pathogenicity of the mutant isolate was shifted from avirulent to virulent on the genotype. Therefore, this mutant is virulence on the identified resistant genes to blackleg disease in genotypes. Superoxide accumulated differently in cotyledons in response to infection with UMAvr7 and umavr7, especially in resistant genotype 01-23-2-1. Resistance/susceptibility was further evaluated on 123 genotypes with the mutant isolate, umavr7. Only 6 of the 123 genotypes showed resistance to umavr7. The identification of these six resistant genotypes will lead to further studies on the development of blackleg disease resistance through breeding and the identification of novel genes.
由真菌病原体引起的黑胫病是影响全球油菜作物的最重要病害。我们利用成簇规律间隔短回文重复序列（CRISPR）/CRISPR相关蛋白（Cas）系统，从一个分离株（UMAvr7）中编码区域的点突变产生了突变分离株umavr7。逆转录PCR和转录组数据证实该基因在突变分离株中被敲除。致病性测试表明，umavr7可在一组表达不同抗性（R）基因的油菜差异基因型上引起大面积病斑。UMAvr7（野生型）和umavr7在相应的油菜基因型01 - 23 - 2 - 1（具有R基因）上的比较致病性测试表明，umavr7是一个突变分离株，在子叶上产生大的灰绿色病斑。该突变分离株在该油菜基因型上的致病性从无毒转变为有毒。因此，该突变体对油菜基因型中已鉴定的抗黑胫病基因具有毒性。超氧化物在子叶中对UMAvr感染和umavr7感染的累积方式不同，尤其是在抗性油菜基因型01 - 23 - 2 - 1中。用突变分离株umavr7对123个油菜基因型的抗性/敏感性进行了进一步评估。123个基因型中只有6个对umavr7表现出抗性。这六个抗性油菜基因型的鉴定将有助于进一步研究通过育种培育抗黑胫病品种以及鉴定新的R基因。
