一种疫霉效应物抑制跨物种 RNAi 以促进易感性。
A Phytophthora Effector Suppresses Trans-Kingdom RNAi to Promote Disease Susceptibility.
机构信息
Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA 92521, USA; Center for Plant Cell Biology, University of California, Riverside, Riverside, CA 92521, USA.
Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China.
出版信息
Cell Host Microbe. 2019 Jan 9;25(1):153-165.e5. doi: 10.1016/j.chom.2018.11.007. Epub 2018 Dec 27.
RNA silencing (RNAi) has a well-established role in anti-viral immunity in plants. The destructive eukaryotic pathogen Phytophthora encodes suppressors of RNAi (PSRs), which enhance plant susceptibility. However, the role of small RNAs in defense against eukaryotic pathogens is unclear. Here, we show that Phytophthora infection of Arabidopsis leads to increased production of a diverse pool of secondary small interfering RNAs (siRNAs). Instead of regulating endogenous plant genes, these siRNAs are found in extracellular vesicles and likely silence target genes in Phytophthora during natural infection. Introduction of a plant siRNA in Phytophthora leads to developmental deficiency and abolishes virulence, while Arabidopsis mutants defective in secondary siRNA biogenesis are hypersusceptible. Notably, Phytophthora effector PSR2 specifically inhibits secondary siRNA biogenesis in Arabidopsis and promotes infection. These findings uncover the role of siRNAs as antimicrobial agents against eukaryotic pathogens and highlight a defense/counter-defense arms race centered on trans-kingdom gene silencing between hosts and pathogens.
RNA 沉默（RNAi）在植物抗病毒免疫中具有既定的作用。破坏性真核病原体 Phytophthora 编码 RNAi 抑制剂（PSRs），增强植物易感性。然而，小 RNA 在防御真核病原体中的作用尚不清楚。在这里，我们表明，拟南芥被 Phytophthora 感染会导致产生大量多样化的次级小干扰 RNA（siRNA）。这些 siRNA 存在于细胞外囊泡中，而不是调节内源性植物基因，并且在自然感染期间可能沉默 Phytophthora 中的靶基因。在 Phytophthora 中引入植物 siRNA 会导致发育缺陷并丧失毒力，而在次级 siRNA 生物发生缺陷的拟南芥突变体中则高度敏感。值得注意的是，植物 PSR2 效应物特异性抑制拟南芥的次级 siRNA 生物发生并促进感染。这些发现揭示了 siRNA 作为针对真核病原体的抗菌剂的作用，并强调了以宿主和病原体之间跨王国基因沉默为中心的防御/反防御军备竞赛。
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