Protein engineering expands the effector recognition profile of a rice NLR immune receptor
Protein engineering expands the effector recognition profile of a rice NLR immune receptor
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DOI：
10.7554/elife.47713
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发表时间：
2019-09-19
期刊：
影响因子：
7.7
通讯作者：
Banfield, Mark J.
中科院分区：
文献类型：
--
作者：
De la Concepcion, Juan Carlos;Franceschetti, Marina;Banfield, Mark J.
植物核苷酸结合，富含亮氨酸重复序列（NLR）受体检测病原体效应物并启动免疫反应。自发现以来，NLR一直是蛋白质工程的焦点，以提高抗病性。然而，这种方法已被证明是具有挑战性的，部分原因是其狭窄的反应特异性。先前，我们揭示了水稻NLR Pikp的整合重金属相关（HMA）结构域识别病原体的结构基础（Maqbool et al.，2015年）。在这里，我们使用结构导向工程来扩展Pikp对稻瘟病病原体效应子AVR-Pik变体的响应谱。位于整合的Pikp-HMA结构域的效应器结合界面内的突变增加了体外和体内对AVR-Pik变体的结合亲和力。这转化为对先前在植物中未被Pikp识别的AVR-Pik变体的扩大的细胞死亡应答。与AVR-Pik变体复合的工程化Pikp-HMA的结构揭示了扩展识别的机制。这些结果提供了一个概念验证，即蛋白质工程可以提高植物NLR受体的效用，其中效应子和NLR之间的直接相互作用被建立，特别是其中这种相互作用通过整合的结构域发生。
Plant nucleotide binding, leucine-rich repeat (NLR) receptors detect pathogen effectors and initiate an immune response. Since their discovery, NLRs have been the focus of protein engineering to improve disease resistance. However, this approach has proven challenging, in part due to their narrow response specificity. Previously, we revealed the structural basis of pathogen recognition by the integrated heavy metal associated (HMA) domain of the rice NLR Pikp (Maqbool et al., 2015). Here, we used structure-guided engineering to expand the response profile of Pikp to variants of the rice blast pathogen effector AVR-Pik. A mutation located within an effector-binding interface of the integrated Pikp-HMA domain increased the binding affinity for AVR-Pik variants in vitro and in vivo. This translates to an expanded cell-death response to AVR-Pik variants previously unrecognized by Pikp in planta. The structures of the engineered Pikp-HMA in complex with AVR-Pik variants revealed the mechanism of expanded recognition. These results provide a proof-of-concept that protein engineering can improve the utility of plant NLR receptors where direct interaction between effectors and NLRs is established, particularly where this interaction occurs via integrated domains.