Unveiling effector-triggered immunity by Plasmodiophora brassicae as a source of durable clubroot disease resistance

揭示芸苔根肿菌效应子触发的免疫作为持久根肿病抗性的来源

• 批准号: RGPIN-2021-02518
• 负责人: PérezLópez, Edel
• 金额: $ 2.4万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=764733
• 关键词: Unveiling; effector; triggered; immunity; Plasmodiophora

Canola industry and the production of cruciferous vegetables in Canada and worldwide has a common enemy: Plasmodiophora brassicae, the clubroot pathogen of the crucifers. P. brassicae is an intracellular protist responsible for millions in losses worldwide. In the last 10 years, clubroot has cost to the canola industry only, around $500 million in losses. The use of resistant varieties has been a key strategy to avoid the damages caused by the pathogen. Over the years, the resistance has been rapidly overcome by new pathotypes of P. brassicae highlighting the need to identify durable sources of resistance. During the infection process, many plant pathogens such as P. brassicae release effector proteins that can suppress plant immunity and allow disease progression. In return, plants have evolved defense mechanisms known as effector-triggered immunity (ETI). This layer of immunity plays a key role in protecting specific plant genotypes against specific pathogen races through intracellular receptors that possess nucleotide-binding leucine-rich repeat (NLR) domains, which recognize pathogen effectors. Effectors conserved among pathogen strains, termed core effectors, have been used as probes to screen for new NLRs to incorporate into breeding programs to generate resistant plants. Recently, different subsets of P. brassicae effectors have been reported, but to date P. brassicae core effectors have yet to be identified. We plan to define P. brassicae core effectors among the different pathotypes identified worldwide using their genomic sequences. We further plan to determine their functionality to elicit ETI (i.e., ETI-eliciting effectors) using the Arabidopsis thaliana-P. brassicae pathosystem model. To unveil this mechanism for P. brassicae, we seek to fulfill the following objectives: 1) to characterize P. brassicae core effectors in terms of degree of conservation among pathotypes and structure of protein families; 2) to identify P. brassicae effectors interacting with A. thaliana NLRs; 3) to identify A. thaliana NLRs associated with P. brassicae effectors; and 4) to determine if those A. thaliana NLRs mediating the interaction with P. brassicae effectors are also present in other Brassica crops. Achieving these objectives will provide original contributions to the understanding of P. brassicae biology and the mechanisms used by the clubroot pathogen to establish infection in the susceptible host. In the longer term, this will lead to the development of plants resistant to P. brassicae and to an environmentally friendly and less costly management of the clubroot disease.

加拿大乃至全世界的油菜产业和十字花科蔬菜生产有一个共同的敌人：十字花科根状茎病原体芸苔根肿菌。芸苔假单胞菌是一种细胞内原生生物，在全球范围内造成数百万的损失。在过去的10年里，根肿病只给油菜籽产业造成了大约5亿美元的损失。利用抗病品种已成为避免病原菌危害的关键策略。多年来，抗性已被新的致病型的芸苔疫霉迅速克服，这突出了鉴定持久抗性来源的需要。在感染过程中，许多植物病原体如芸苔疫霉释放可抑制植物免疫并允许疾病进展的效应蛋白。作为回报，植物进化出了被称为效应子触发免疫（ETI）的防御机制。这层免疫在保护特定植物基因型抵抗特定病原体小种中起关键作用，其通过具有识别病原体效应物的核苷酸结合富亮氨酸重复（NLR）结构域的细胞内受体。在病原体菌株中保守的效应子，称为核心效应子，已被用作探针来筛选新的NLR以并入育种程序以产生抗性植物。最近，已经报道了芸苔疫霉效应子的不同子集，但迄今为止尚未鉴定出芸苔疫霉核心效应子。我们计划使用其基因组序列在全世界鉴定的不同致病型中定义芸苔疫霉核心效应子。我们进一步计划确定它们引起ETI的功能（即，ETI-诱导效应物）。为了揭示这一机制，我们试图实现以下目标：1）根据致病型之间的保守程度和蛋白质家族的结构来表征P. brassicae核心效应子; 2）鉴定P. brassicae与A. thaliana NLRs; 3）鉴定A. thaliana NLR与P. brassicae效应子相关;以及4）确定那些A.介导与P. brassicae效应子相互作用的拟南芥NLR也存在于其它芸苔属作物中。实现这些目标将提供原始的贡献，以了解P.芸苔生物学和根肿病病原体在易感宿主中建立感染的机制。从长远来看，这将导致植物对P. brassicae的抗性的发展，以及对根肿病的环境友好和成本较低的管理。