Data_Sheet_2_Nitrogen Supply and Host-Plant Genotype Modulate the Transcriptomic Profile of Plasmodiophora brassicae.PDF

Nitrogen fertilization can affect the susceptibility of Brassica napus to the telluric pathogen Plasmodiophora brassicae. Our previous works highlighted that the influence of nitrogen can strongly vary regarding plant cultivar/pathogen strain combinations, but the underlying mechanisms are unknown. The present work aims to explore how nitrogen supply can affect the molecular physiology of P. brassicae through its life epidemiological cycle. A time-course transcriptome experiment was conducted to study the interaction, under two conditions of nitrogen supply, between isolate eH and two B. napus genotypes (Yudal and HD-018), harboring (or not harboring) low nitrogen-conditional resistance toward this isolate (respectively). P. brassicae transcriptional patterns were modulated by nitrogen supply, these modulations being dependent on both host-plant genotype and kinetic time. Functional analysis allowed the identification of P. brassicae genes expressed during the secondary phase of infection, which may play a role in the reduction of Yudal disease symptoms in low-nitrogen conditions. Candidate genes included pathogenicity-related genes (“NUDIX,” “carboxypeptidase,” and “NEP-proteins”) and genes associated to obligate biotrophic functions of P. brassicae. This work illustrates the importance of considering pathogen’s physiological responses to get a better understanding of the influence of abiotic factors on clubroot resistance/susceptibility.

氮肥施用可影响甘蓝型油菜（Brassica napus）对土传病原菌芸薹根肿菌（Plasmodiophora brassicae）的感病性。此前我们的研究表明，氮肥的影响会因植物品种/病原菌菌株的组合不同而产生显著差异，但其背后的分子机制尚不明晰。本研究旨在探究供氮水平如何通过芸薹根肿菌的侵染生活史，影响其分子生理特性。本研究设置两种供氮水平，开展时序转录组实验以探究菌株eH与两种甘蓝型油菜基因型（Yudal和HD-018）之间的互作关系；其中Yudal对该菌株具有低氮依赖型抗性，而HD-018则无此抗性。芸薹根肿菌的转录模式受供氮水平调控，且这种调控作用同时依赖于宿主植物基因型与侵染时序。通过功能分析，本研究鉴定出在侵染次级阶段表达的芸薹根肿菌基因，这些基因可能在低氮条件下减轻Yudal的病害症状过程中发挥作用。候选基因包括致病相关基因（如"NUDIX家族基因"、"羧肽酶"以及"NEP蛋白家族基因"）以及与芸薹根肿菌专性寄生营养功能相关的基因。本研究阐明，若要更深入理解非生物因子对根肿病抗性/感病性的影响，必须考虑病原菌的生理响应，这一点至关重要。