Cross-reactivity of a rice NLR immune receptor to distinct effectors from the blast pathogen leads to partial disease resistance
Cross-reactivity of a rice NLR immune receptor to distinct effectors from the blast pathogen leads to partial disease resistance
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水稻 NLR 免疫受体与稻瘟病原菌的不同效应子的交叉反应导致部分抗病性
DOI：
10.1101/530675
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
M.J.
中科院分区：
文献类型：
--
作者：
Varden;F.A.;Saitoh;H.;Yoshino;K.;Franceschetti;M.;Kamoun;S.;Terauchi;R.;Banfield;M.J.
植物细胞内免疫受体（NLR）中的非常规整合结构域可以直接结合易位的病原体效应蛋白以启动免疫应答。水稻免疫受体对Pik-1/Pik-2和RGA 5/RGA 4均利用整合的重金属相关（HMA）结构域分别与稻瘟病菌效应子AVR-Pik和AVR-Pia结合。这些效应子都属于MAX效应子家族，并且共享核心结构折叠，尽管序列不同。整合的结构域如何保持识别的特异性，即使是结构相似的效应子，对理解植物免疫受体的进化和功能具有重要意义。在这里，我们表明，水稻NLR对Pikp-1/Pikp-2触发的免疫反应，导致部分抗病性对“错配”效应AVR-Pia在植物中，和Pikp-HMA结构域结合AVR-Pia在体外。来自另一个Pik-1等位基因Pikm的HMA结构域不能结合AVR-Pia，并且不会在植物中引发反应。与AVR-Pia结合的Pikp-HMA的晶体结构揭示了与AVR-Pik效应物相比不同的结合界面，表明了整合结构域/效应物相互作用的可塑性。这项工作显示了单个NLR如何通过整合的结构域诱饵多种病原体效应物，并可能使工程免疫受体具有扩展的抗病性。
Unconventional integrated domains in plant intracellular immune receptors (NLRs) can directly bind translocated pathogen effector proteins to initiate an immune response. The rice immune receptor pairs Pik-1/Pik-2 and RGA5/RGA4 both use integrated heavy metal-associated (HMA) domains to bind theMagnaporthe oryzaeeffectors AVR-Pik and AVR-Pia, respectively. These effectors both belong to the MAX effector family and share a core structural fold, despite being divergent in sequence. How integrated domains maintain specificity of recognition, even for structurally similar effectors, has implications for understanding plant immune receptor evolution and function. Here we show that the rice NLR pair Pikp-1/Pikp-2 triggers an immune response leading to partial disease resistance towards the “mismatched” effector AVR-Pia in planta, and that the Pikp-HMA domain binds AVR-Pia in vitro. The HMA domain from another Pik-1 allele, Pikm, is unable to bind AVR-Pia, and does not trigger a response in plants. The crystal structure of Pikp-HMA bound to AVR-Pia reveals a different binding interface compared to AVR-Pik effectors, suggesting plasticity in integrated domain/effector interactions. This work shows how a single NLR can bait multiple pathogen effectors via an integrated domain, and may enable engineering immune receptors with extended disease resistance profiles.