Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610000, China.
Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China.
Phytopathology. 2021 Nov;111(11):2067-2079. doi: 10.1094/PHYTO-08-20-0321-R. Epub 2021 Nov 11.
Reactive oxygen species (ROSs) are critical for the growth, development, proliferation, and pathogenicity of microbial pathogens; however, excessive levels of ROSs are toxic. Little is known about the signaling cascades in response to ROS stress in oomycetes such as , the causal agent of potato late blight. Here, was used as a model system to investigate the mechanism underlying the response to ROS stress in oomycete pathogens. Results showed severe defects in sporangium germination, mycelium growth, appressorium formation, and virulence of in response to HO stress. Importantly, these phenotypes mimic those of treated with rapamycin, the inhibitor of target of rapamycin (TOR, 1-phosphatidylinositol-3-kinase). Strong synergism occurred when was treated with a combination of HO and rapamycin, suggesting that a crosstalk exists between ROS stress and the TOR signaling pathway. Comprehensive analysis of transcriptome, proteome, and phosphorylation omics showed that HO stress significantly induced the operation of the TOR-mediated autophagy pathway. Monodansylcadaverine staining showed that in the presence of HO and rapamycin, the autophagosome level increased in a dosage-dependent manner. Furthermore, transgenic potatoes containing double-stranded RNA of in () displayed high resistance to . Therefore, TOR is involved in the ROS response and is a potential target for control of oomycete diseases, because host-mediated silencing of increases potato resistance to late blight.
活性氧 (ROS) 对微生物病原体的生长、发育、增殖和致病性至关重要；然而，ROS 水平过高是有毒的。关于卵菌如马铃薯晚疫病的病原体，对 ROS 应激的信号级联知之甚少。在这里， 被用作模型系统来研究卵菌病原体对 ROS 应激的反应机制。结果表明，在 HO 应激下，游动孢子萌发、菌丝生长、附着胞形成和 的毒性严重缺陷。重要的是，这些表型类似于用雷帕霉素（TOR，1-磷酸肌醇-3-激酶的抑制剂）处理的 。当 与 HO 和雷帕霉素联合处理时，会发生强烈的协同作用，表明 ROS 应激和 TOR 信号通路之间存在串扰。对转录组、蛋白质组和磷酸化组学的综合分析表明，HO 应激显著诱导 TOR 介导的自噬途径的运作。单丹磺酰尸胺染色表明，在存在 HO 和雷帕霉素的情况下，自噬体水平呈剂量依赖性增加。此外，含有 双链 RNA 的转基因马铃薯（ ）对 表现出高抗性。因此，TOR 参与 ROS 反应，是控制卵菌病害的潜在靶标，因为宿主介导的沉默 增加了马铃薯对晚疫病的抗性。
