An RxLR effector from Plasmopara viticola suppresses plant immunity in grapevine by targeting and stabilizing VpBPA1
An RxLR effector from Plasmopara viticola suppresses plant immunity in grapevine by targeting and stabilizing VpBPA1
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DOI：
10.1111/tpj.15933
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发表时间：
2022-08-19
期刊：
影响因子：
7.2
通讯作者：
Xu, Yan
中科院分区：
文献类型：
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作者：
Yin, Xiao;Fu, Qingqing;Xu, Yan
葡萄霜霉病是葡萄栽培中最具破坏性的病害之一，由葡萄浆原菌引起。葡萄浆原分泌RxLR效应物调节葡萄免疫应答。在这里，我们报道了一种来自葡萄霉的RxLR效应物RxLR50253，它可以干扰植物的免疫应答，从而促进病原体的定植。RxLR50253在葡萄假单胞菌感染早期诱导表达，可抑制诱导子（INF1和Bax）引发的细胞死亡。RxLR50253促进病原菌在烟草和葡萄叶片中的定植。通过酵母双杂交筛选发现VpBPA1是RxLR50253的宿主靶点，并通过多次体内外实验证实了VpBPA1与RxLR50253之间的相互作用。进一步分析发现，VpBPA1促进了病原菌在转基因烟草和葡萄中的定殖，降低了H2O2积累，而nbbpa1沉默的本烟叶片的抗性和H2O2积累增强。此外，在nbbpa1沉默的benthamiana叶片中，VpBPA1的瞬时表达可以减少H2O2的积累。体内实验证明RxLR50253能够抑制VpBPA1的降解。综上所述，我们的研究结果表明，RxLR50253通过降低病原菌侵染过程中H2O2的积累，靶向并稳定VpBPA1，从而减弱植物免疫力。
Grapevine downy mildew, caused by Plasmopara viticola, is one of the most devastating diseases in viticulture. Plasmopara viticola secretes RxLR effectors to modulate immune responses in grapevine. Here, we report an RxLR effector RxLR50253 from P. viticola that can interfere with plant immune response and thus promote pathogen colonization. RxLR50253 was induced at an early stage of P. viticola infection and could suppress elicitor (INF1 and Bax)-triggered cell death. RxLR50253 promote pathogen colonization in both tobacco and grapevine leaves. VpBPA1 was found to be the host target of RxLR50253 by yeast two-hybrid screening, and interaction between RxLR50253 and VpBPA1 was confirmed by multiple in vivo and in vitro assays. Further analysis revealed that VpBPA1 promoted pathogen colonization and decreased H2O2 accumulation in transgenic tobacco and grapevine, while there was enhanced resistance and H2O2 accumulation in NbBPA1-silenced Nicotiana benthamiana leaves. Moreover, transient expression of VpBPA1 in NbBPA1-silenced N. benthamiana leaves could reduce the accumulation of H2O2. Experiments in vivo demonstrated that RxLR50253 inhibits degradation of VpBPA1. Taken together, our findings showed that RxLR50253 targets and stabilizes VpBPA1 to attenuate plant immunity through decreasing H2O2 accumulation during pathogen infection.