通过定量蛋白组学研究OsGLO1对稻瘟病抗性的调控机制

[目的]水稻葡糖酸氧化酶1（OsGLO1）定位于水稻过氧化物酶体（peroxisome），参与过氧化氢的产生，但其是否参与水稻对稻瘟病抗性的调控还未见报道。本研究的目的是为了考察OsGLO1在水稻对稻瘟病抗性中的作用。[方法]以水稻‘日本晴’和稻瘟病病菌互作体系为研究对象，使用定量蛋白质组学技术，比较和分析了亲和型和非亲和型稻瘟病菌菌株侵染引起的水稻蛋白质表达变化。[结果]研究发现水稻OsGLO1蛋白的表达受到亲和型稻瘟病菌侵染的特异性抑制，但是在非亲和反应中的表达量变化则不明显。水稻原生质体过表达和沉默试验证明，OsGLO1的表达与水稻活性氧积累以及胼胝质沉积量呈正相关，且OsGLO1过表达诱发水杨酸（SA）和茉莉酸（JA）等多种防卫信号通路相关基因的表达。[结论]OsGLO1可以激活水稻的早期防卫反应，并通过启动多种激素信号通路维持水稻对稻瘟病一定水平的抗性。考虑到其也参与植物对非生物胁迫抗性的调控，提示OsGLO1可能是水稻抵抗生物胁迫以及非生物胁迫中的重要因子。
[Objectives]OsGLO1(glycolate-oxidase 1) is a peroxisome-localized enzyme catalyzing hydrogen peroxide(H2O2) production. However,it remains uninvestigated whether OsGLO1 contributes to the rice defense response. Therefore,it is of great significance studying the involvement of OsGLO1 in rice defense against the blast disease,the most severe rice disease worldwide. [Methods]We compared and analyzed the rice protein expression profiles between the rice leaves inoculated by a Magnaporthe oryzae compatible(Guy11) and an incompatible strain(2539) with the mock-treated rice leaves through a quantitative proteomic approach. [Results]We found that OsGLO1 was specifically suppressed by the compatible rice blast strain but not by the incompatible strain. Guy11 is a virulent strain that causes noticeable disease symptoms on rice,whereas strain 2539 is an avirulent strain that is moderately pathogenic to many rice genotypes. Therefore,the suppressed OsGLO1 expression by Guy11 and the declined disease resistance after Guy11 infection associate OsGLO1 with blast disease resistance. By employing a rice protoplast-M. oryzae elicitor interaction system,we confirmed that the expression of OsGLO1 was positively related to rice early defense responses such as reactive oxygen species(ROS) accumulation and callose deposition. Moreover,cognate expression profiles were also observed between OsGLO1 and multiple defense signaling pathway components such as OsPBZ1,OsPAD4 and OsAOS2. [Conclusions]Our results suggest that OsGLO1 is a defense component involved in disease response against rice blast,in which multiple phytohormone signaling pathway are employed. Our study is the first case study that OsGLO1 is a critical component against rice blast disease. Considering its involvement in abiotic stress tolerance,our discovery is of great significance revealing that OsGLO1 might play mutual roles against both abiotic and biotic stresses