Two NLR immune receptors acquired high-affinity binding to a fungal effector through convergent evolution of their integrated domain.
Two NLR immune receptors acquired high-affinity binding to a fungal effector through convergent evolution of their integrated domain.
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DOI：
10.7554/elife.66961
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发表时间：
2021-07-21
期刊：
影响因子：
7.7
通讯作者：
Kamoun S
中科院分区：
文献类型：
--
作者：
Białas A;Langner T;Harant A;Contreras MP;Stevenson CE;Lawson DM;Sklenar J;Kellner R;Moscou MJ;Terauchi R;Banfield MJ;Kamoun S
植物NLR免疫受体的一个子集除了其规范的结构域结构外，还带有非传统的整合域。一个例子是大米Pik-1，它包含一个整合的重金属相关结构域(HMA)。在这里，我们重建了Pik-1及其NLR伙伴Pik-2的进化史，并检验了有关HMA结构域适应性进化的假设。系统发育分析表明，在1500万年前稻亚科物种形成之前，HMA结构域已经整合到Pik-1中，并一直处于多样化选择之下。祖先序列重构结合功能研究表明，两个Pik-1等位基因变异独立地从弱结合祖先状态进化到高亲和力结合稻瘟菌效应器AVR-PikD。我们得出结论，在其进化史的大部分时间里，Pik-1 HMA结构域没有感知AVR-PikD，并且不同的Pik-1受体最近通过不同的生化途径进化来产生相似的表型结果。这些发现突出了NLR适应植物病原体的进化机制的动态本质。
A subset of plant NLR immune receptors carry unconventional integrated domains in addition to their canonical domain architecture. One example is rice Pik-1 that comprises an integrated heavy metal-associated (HMA) domain. Here, we reconstructed the evolutionary history of Pik-1 and its NLR partner, Pik-2, and tested hypotheses about adaptive evolution of the HMA domain. Phylogenetic analyses revealed that the HMA domain integrated into Pik-1 before Oryzinae speciation over 15 million years ago and has been under diversifying selection. Ancestral sequence reconstruction coupled with functional studies showed that two Pik-1 allelic variants independently evolved from a weakly binding ancestral state to high-affinity binding of the blast fungus effector AVR-PikD. We conclude that for most of its evolutionary history the Pik-1 HMA domain did not sense AVR-PikD, and that different Pik-1 receptors have recently evolved through distinct biochemical paths to produce similar phenotypic outcomes. These findings highlight the dynamic nature of the evolutionary mechanisms underpinning NLR adaptation to plant pathogens.