Plasmopara viticola, the casual oomycete of grapevine downy mildew, could cause yield loss and compromise berry quantity. Previously, we have identified several PvRXLR effectors that could suppress plant immunity to promote infection and disease development. In this study, the role of effector, PvRXLR53, in plant-microbe interaction was investigated. PvRXLR53 has several orthologs in other oomycetes and contains a functional signal peptide. Expression level of PvRXLR53 was already detected upon inoculation, further induced in the early stage after P. viticola inoculation and decreased to low level in the late infection stage in grapevine (Vitis vinifera 'Cabernet Sauvignon'). PvRXLR53 is localized in both nucleus and cytoplasm. When transiently expressed in Nicotiana benthamiana, PvRXLR53 suppressed oomycete elicitor INF1-triggered programmed cell death and defense gene expression, and Phytophthora capsici-induced reactive oxygen species production (ROS) and eventually resistance to P. capsici. In summary, these findings suggest that P. viticola secretes PvRXLR53 to suppress host immunity from the very early stage of infection.

中文翻译：

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葡萄生单轴霉效应子 PvRXLR53 抑制本塞姆氏烟草的先天免疫


葡萄单轴霉（Plasmopara viticola）是葡萄霜霉病的偶然卵菌，可能会导致产量损失并影响浆果数量。此前，我们已经鉴定出几种 PvRXLR 效应子可以抑制植物免疫，从而促进感染和疾病发展。在本研究中，研究了效应子 PvRXLR53 在植物-微生物相互作用中的作用。 PvRXLR53 在其他卵菌中具有多种直向同源物，并含有功能性信号肽。 PvRXLR53的表达水平在接种时就已被检测到，并在接种P. viticola后的早期被进一步诱导，并在葡萄树（Vitis vinifera ‘Cabernet Sauvignon’）感染后期降至低水平。 PvRXLR53 定位于细胞核和细胞质中。当在本塞姆氏烟草中瞬时表达时，PvRXLR53 抑制卵菌激发子 INF1 触发的程序性细胞死亡和防御基因表达，以及辣椒疫霉诱导的活性氧生成 (ROS) 并最终抑制辣椒疫病菌的抗性。总之，这些发现表明 P. viticola 分泌 PvRXLR53 从感染的早期阶段抑制宿主免疫。