Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany.
College of Plant Sciences, Jilin University, 130062, Changchun, China.
Plant Cell Environ. 2017 Oct;40(10):2189-2206. doi: 10.1111/pce.13022. Epub 2017 Aug 17.
The large WRKY transcription factor family is mainly involved in regulating plant immune responses. Arabidopsis WRKY33 is a key transcriptional regulator of hormonal and metabolic processes towards Botrytis cinerea strain 2100 infection and is essential for resistance. In contrast to B. cinerea strain 2100, the strain B05.10 is virulent on wild-type (WT) Col-0 Arabidopsis plants highlighting the genetic diversity within this pathogen species. We analysed how early WRKY33-dependent responses are affected upon infection with strain B05.10 and found that most of these responses were strongly dampened during this interaction. Ectopic expression of WRKY33 resulted in complete resistance towards this strain indicating that virulence of B05.10, at least partly, depends on suppressing WRKY33 expression/protein accumulation. As a consequence, the expression levels of direct WRKY33 target genes, including those involved in the biosynthesis of camalexin, were also reduced upon infection. Concomitantly, elevated levels of the phytohormone abscisic acid (ABA) were observed. Molecular and genetic studies revealed that ABA negatively influences defence to B05.10 and effects jasmonic acid/ethylene (JA/ET) and salicylic acid (SA) levels. Susceptibility/resistance was determined by the antagonistic effect of ABA on JA, and this crosstalk required suppressing WRKY33 functions at early infection stages. This indicates that B. cinerea B05.10 promotes disease by suppressing WRKY33-mediated host defences.
WRKY 转录因子家族主要参与植物免疫反应的调控。拟南芥 WRKY33 是激素和代谢过程对 Botrytis cinerea 菌株 2100 感染的关键转录调节因子，对抵抗至关重要。与 B. cinerea 菌株 2100 相反，菌株 B05.10 对野生型（WT）Col-0 拟南芥植物具有毒力，突出了该病原体种内的遗传多样性。我们分析了在感染菌株 B05.10 时早期依赖 WRKY33 的反应如何受到影响，发现在此相互作用过程中，这些反应中的大多数受到强烈抑制。WRKY33 的异位表达导致对该菌株的完全抗性，表明 B05.10 的毒力至少部分取决于抑制 WRKY33 的表达/蛋白积累。因此，WRKY33 的直接靶基因的表达水平，包括参与 camalexin 生物合成的基因，在感染后也降低。同时，观察到植物激素脱落酸（ABA）的水平升高。分子和遗传研究表明，ABA 负向影响对 B05.10 的防御，并且影响茉莉酸/乙烯（JA/ET）和水杨酸（SA）的水平。敏感性/抗性由 ABA 对 JA 的拮抗作用决定，这种串扰需要在早期感染阶段抑制 WRKY33 功能。这表明 B. cinerea B05.10 通过抑制 WRKY33 介导的宿主防御来促进疾病。
