稻曲病菌SIX效应蛋白参与调控植物免疫

为明确稻曲病菌Ustilaginoidea virens的SIX(secreted in xylem)效应蛋白功能,利用生物信息学软件预测6个SIX1蛋白和1个SIX2蛋白的分泌特性,并通过酵母分泌系统对其分泌特性进行验证,在烟草上通过根癌农杆菌Agrobacterium tumefaciens介导的瞬时表达系统检测SIX蛋白对小鼠促凋亡蛋白BAX、致病疫霉Phytophthora infestans激发子INF1、大豆疫霉Phytophthora sojae病原相关分子模式糖基水解酶XEG1引起烟草细胞坏死的作用,在烟草上表达SIX蛋白后接种辣椒疫霉Phytophthora capsici并观察其对辣椒疫霉侵染的作用。结果显示:所检测的SIX蛋白中有5个含有预测的信号肽,2个被预测为非经典分泌蛋白,但经酵母分泌系统验证均具有分泌功能;大部分SIX蛋白能够抑制BAX、INF1、XEG1引起的烟草细胞坏死,但抑制坏死的情况并不完全一致;大部分含信号肽的SIX蛋白能够促进辣椒疫霉侵染,UV8b＿3638去信号肽突变体也能够促进辣椒疫霉侵染。表明大多数SIX蛋白参与调控植物免疫,且能促进病原...

SIX effectors of rice false smut pathogen Ustilaginoidea virens are involved in regulation of plant immunity

In order to reveal the function of six SIX1 and one SIX2 effectors in rice false smut pathogen Ustilaginoidea virens, the secretory characteristics of SIX (secreted in xylem) proteins were identified through bioinformatics analysis and further verified by using the yeast system. The Agrobacterium tumefaciens-mediated transient expression system in Nicotiana benthamiana was used to identify whether SIX proteins had the ability to suppress cell death induced by mouse apoptosis regulator BAX, Phytophthora infestans elicitor INF1, and Phytophthora sojae pathogen-associated molecular patterns glycoside hydrolase XEG1. The N. benthamiana leaves expressing SIX proteins were inoculated with Phytophthora capsici to evaluate the contribution of infection. The results showed that five of the seven SIX effectors had signal peptides and the other two were predicted to be non-classical secreted proteins, all of which were verified to have secretory function. Most of SIX proteins exhibited the ability of cell death suppression when co-expressed with BAX, INF1, XEG1, respectively, but their results varied to some extent. Most of proteins with signal peptides and UV8b_3638 without a signal peptide were able to promote the infection. The results indicated that the most of SIX proteins were involved in the regulation of plant immunity and can promote the infection of plant by pathogens.