PDF(Pubmed)
Abstract：
NLR family proteins act as intracellular receptors. Gene duplication amplifies the number of NLR genes, and subsequent mutations occasionally provide modifications to the second gene that benefits immunity. However, evolutionary processes after gene duplication and functional relationships between duplicated NLRs remain largely unclear. Here, we report that the rice NLR protein Pit1 is associated with its paralogue Pit2. The two are required for the resistance to rice blast fungus but have different functions: Pit1 induces cell death, while Pit2 competitively suppresses Pit1-mediated cell death. During evolution, the suppression of Pit1 by Pit2 was probably generated through positive selection on two fate-determining residues in the NB-ARC domain of Pit2, which account for functional differences between Pit1 and Pit2. Consequently, Pit2 lost its plasma membrane localization but acquired a new function to interfere with Pit1 in the cytosol. These findings illuminate the evolutionary trajectory of tandemly duplicated NLR genes after gene duplication.
摘要：
NLR家族蛋白充当细胞内受体。基因复制放大了NLR基因的数量，随后的突变偶尔会对第二个基因进行修饰，从而有益于免疫。然而,基因复制后的进化过程以及复制的NLR之间的功能关系仍不清楚。这里,我们报道了水稻NLR蛋白Pit1与其旁系物Pit2相关。两者是抗稻瘟病菌所必需的，但具有不同的功能：Pit1诱导细胞死亡，而Pit2竞争性抑制Pit1介导的细胞死亡。在进化过程中,Pit2对Pit1的抑制可能是通过对Pit2的NB-ARC结构域中的两个命运决定残基的阳性选择而产生的，这解释了Pit1和Pit2之间的功能差异。因此,Pit2失去了其质膜定位，但获得了干扰细胞溶质中Pit1的新功能。这些发现阐明了基因复制后串联复制的NLR基因的进化轨迹。
