Bai Xingxuan, Peng Huan, Goher Farhan, Islam Md Ashraful, Xu Sanding, Guo Jia, Kang Zhensheng, Guo Jun
State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China.
Stress Biol. 2022 Apr 8;2(1):21. doi: 10.1007/s44154-022-00042-5.
Common in Fungal Extracellular Membrane (CFEM) domain proteins are considered to be unique to fungi and closely related to pathogenicity. However, the Puccinia striiformis f. sp. tritici (Pst) effector containing the CFEM domain has not been reported. Here, we obtained an effector, PstCFEM1, containing a functional N-terminal signal peptide sequence and the CFEM domain from Pst race CYR31. qRT-PCR assay indicated that the transcript levels of PstCFEM1 were highly induced during the early stages of infection. Overexpression of PstCFEM1 suppressed Pst322 (an elicitor-like protein of Pst)-trigged cell death, reactive oxygen species (ROS) accumulation and callose deposition. Host-induced gene silencing (HIGS) experiments showed that knockdown of PstCFEM1 decreased the virulence of Pst, while ROS accumulation in silenced plants increased near the infection site. In addition, wheat containing the PstCFEM1-silenced construct increased resistance to multiple races of Pst. Our data suggest that PstCFEM1 suppresses wheat defense by inhibiting ROS accumulation and contributes to increased virulence of Pst.
真菌细胞外膜（CFEM）结构域蛋白在真菌中很常见，被认为是真菌特有的，且与致病性密切相关。然而，尚未有关于含有CFEM结构域的条锈菌（Puccinia striiformis f. sp. tritici，Pst）效应子的报道。在此，我们从条锈菌小种CYR31中获得了一个效应子PstCFEM1，它含有一个功能性的N端信号肽序列和CFEM结构域。qRT-PCR分析表明，PstCFEM1的转录水平在侵染早期受到高度诱导。PstCFEM1的过表达抑制了Pst322（条锈菌的一种类激发子蛋白）触发的细胞死亡、活性氧（ROS）积累和胼胝质沉积。寄主诱导的基因沉默（HIGS）实验表明，PstCFEM1的敲低降低了条锈菌的毒力，而沉默植株中感染部位附近的ROS积累增加。此外，含有PstCFEM1沉默构建体的小麦对多个条锈菌小种的抗性增强。我们的数据表明，PstCFEM1通过抑制ROS积累来抑制小麦的防御反应，并有助于条锈菌毒力的增强。
