Single Amino Acid Mutations in the Potato Immune Receptor R3a Expand Response to Phytophthora Effectors
Single Amino Acid Mutations in the Potato Immune Receptor R3a Expand Response to Phytophthora Effectors
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DOI：
10.1094/mpmi-02-14-0040-r
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发表时间：
2014-07-01
影响因子：
3.5
通讯作者：
Kamoun, Sophien
中科院分区：
文献类型：
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作者：
Eugenia Segretin, Maria;Pais, Marina;Kamoun, Sophien
植物和动物都依赖于含有核苷酸结合结构域和富含亮氨酸重复序列（NB-LRR或NLR）的蛋白质来响应入侵病原体并激活免疫反应。植物NB-LRR蛋白如何响应病原体的了解甚少。我们对马铃薯NB-LRR免疫受体R3 a进行了功能获得性随机诱变筛选，以研究这种蛋白质如何响应来自卵菌病原体致病疫霉的效应蛋白AVR 3a。R3 a反应可以延伸到效应器的隐形AVR 3a（EM）同种型，同时保留对AVR 3a（KI）的识别。八个单一氨基酸突变中的每一个都足以扩大R3 a对AVR 3a（EM）和其他AVR 3a变体的应答。这些突变发生在R3 a蛋白上，从N末端到LRR结构域的不同区域。这些R3 a突变体的进一步表征揭示，它们中的至少一个是致敏的，表现出比野生型R3 a蛋白对AVR 3a（KI）更强的反应。值得注意的是，靠近R3 a核苷酸结合口袋的N336 Y突变赋予了对来自蔬菜病原体辣椒疫霉的效应蛋白PcAVR 3a 4的响应。这项工作有助于了解如何NB-LRR受体特异性可以调制。结合病原体效应子多样性的知识，可以利用这种策略来开发合成免疫受体。
Both plants and animals rely on nucleotide-binding domain and leucine-rich repeat-containing (NB-LRR or NLR) proteins to respond to invading pathogens and activate immune responses. How plant NB-LRR proteins respond to pathogens is poorly understood. We undertook a gain-of-function random mutagenesis screen of the potato NB-LRR immune receptor R3a to study how this protein responds to the effector protein AVR3a from the oomycete pathogen Phytophthora infestans. R3a response can be extended to the stealthy AVR3a(EM) isoform of the effector while retaining recognition of AVR3a(KI). Each one of eight single amino acid mutations is sufficient to expand the R3a response to AVR3a(EM) and other AVR3a variants. These mutations occur across the R3a protein, from the N terminus to different regions of the LRR domain. Further characterization of these R3a mutants revealed that at least one of them was sensitized, exhibiting a stronger response than the wild-type R3a protein to AVR3a(KI). Remarkably, the N336Y mutation, near the R3a nucleotide-binding pocket, conferred response to the effector protein PcAVR3a4 from the vegetable pathogen P. capsici. This work contributes to understanding how NB-LRR receptor specificity can be modulated. Together with knowledge of pathogen effector diversity, this strategy can be exploited to develop synthetic immune receptors.