Functional divergence of duplicated genes results in a novel blast resistance gene Pi50 at the Pi2/9 locus
Functional divergence of duplicated genes results in a novel blast resistance gene Pi50 at the Pi2/9 locus
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重复基因的功能差异导致 Pi2/9 位点产生新的稻瘟病抗性基因 Pi50
DOI：
10.1007/s00122-015-2579-9
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发表时间：
2015-11-01
影响因子：
5.4
通讯作者：
Zhu, Xiaoyuan
中科院分区：
文献类型：
--
作者：
Su, Jing;Wang, Wenjuan;Zhu, Xiaoyuan
我们在Pi 2/9位点鉴定了一个新的稻瘟病抗性基因Pi 50; Pi 50来自重复基因的功能分歧。Pi 50的独特功能将有助于其在水稻育种中的应用，并提高我们对抗性特异性进化的理解。由稻瘟病菌（Magnaporthe）引起的稻瘟病对全世界水稻的稳定生产构成持续的主要威胁。广谱抗病基因的应用为病害控制提供了最有效和最经济的手段。在这项研究中，我们的特点是广谱R基因Pi 50在Pi 2/9位点，这是嵌入在一个串联簇的12个基因编码的蛋白质与核苷酸结合位点和亮氨酸丰富的重复（NBS-LRR）域。与其他Pi 2/9基因座相比，Pi 50簇包含4个重复基因（Pi50_NBS4_1至4），具有极高的核苷酸序列相似性。此外，这些重复的基因编码两种蛋白质（Pi50_NBS4_1/2和Pi50_NBS4_3/4），这两种蛋白质相差4个氨基酸。互补测试和抗性谱分析显示，Pi50_NBS4_1/2而不是Pi50_NBS4_3/4控制新的抗性特异性，如在Pi 50近等基因系NIL-e1中观察到的。Pi 50与其他三种R蛋白中的每一种共享大于96%的氨基酸序列同一性，即，Pi 9、Piz-t和Pi 2，并且主要在LRR区域内具有氨基酸变化。鉴定Pi 50及其新的抗性特异性将有助于剖析Pi 2/9位点上不同抗性特异性的分歧和进化背后的机制。
We characterized a novel blast resistance gene Pi50 at the Pi2/9 locus; Pi50 is derived from functional divergence of duplicated genes. The unique features of Pi50 should facilitate its use in rice breeding and improve our understanding of the evolution of resistance specificities. Rice blast disease, caused by the fungal pathogen Magnaporthe oryzae, poses constant, major threats to stable rice production worldwide. The deployment of broad-spectrum resistance (R) genes provides the most effective and economical means for disease control. In this study, we characterize the broad-spectrum R gene Pi50 at the Pi2/9 locus, which is embedded within a tandem cluster of 12 genes encoding proteins with nucleotide-binding site and leucine-rich repeat (NBS-LRR) domains. In contrast with other Pi2/9 locus, the Pi50 cluster contains four duplicated genes (Pi50_NBS4_1 to 4) with extremely high nucleotide sequence similarity. Moreover, these duplicated genes encode two kinds of proteins (Pi50_NBS4_1/2 and Pi50_NBS4_3/4) that differ by four amino acids. Complementation tests and resistance spectrum analyses revealed that Pi50_NBS4_1/2, not Pi50_NBS4_3/4, control the novel resistance specificity as observed in the Pi50 near isogenic line, NIL-e1. Pi50 shares greater than 96 % amino acid sequence identity with each of three other R proteins, i.e., Pi9, Piz-t, and Pi2, and has amino acid changes predominantly within the LRR region. The identification of Pi50 with its novel resistance specificity will facilitate the dissection of mechanisms behind the divergence and evolution of different resistance specificities at the Pi2/9 locus.