烟草泛素化相关基因NbRGLG2和NbUBXN6负调控SRC7而影响植物抗性

Tobacco Ubiquitination-Related Genes NbRGLG2 and NbUBXN6 Affect Plant Immunity through Negatively Regulating SRC7

泛素化修饰是一种蛋白质降解调控的重要途径,而E3泛素连接酶是泛素化系统的关键组分,结合并决定靶标蛋白。前期研究中从大豆中克隆了一个广谱抗病基因SRC7(SMV resistance cluster 7),其主要功能结构域是TN(TIR-NBS)结构域。本氏烟草(Nicotiana benthamiana)中两个编码泛素相关的蛋白NbRGLG2和NbUBXN6均与SRC7^(TN)具有互作。瞬时表达实验中NbRGLG2与NbUBXN6对SMV和TMV无抗性。然而,NbRGLG2与NbUBXN6与SRC7^(TN)共表达时,都会抑制SRC7^(TN)的抗病毒活性。过表达SRC7(Ox-SRC7)本氏烟草中沉默NbRGLG2基因和NbUBXN6基因时,它们可以增强SRC7^(TN)对SMV和TMV的抗性。这些结果显示,NbRGLG2与NbUBXN6负调控SRC7的抗病毒活性。

Ubiquitination is an important pathway for protein degradation,and E3 ligase is a key component of the ubiquitination system,binding to and determining target proteins.In previous research,we cloned a broad-spectrum disease resistance gene SRC7(SMV resistance cluster 7) from soybean,and confirmed that main functional domain of SRC7 was the TN(TIR-NBS) domain.Two ubiquitin-related proteins in Nicotiana benthamiana,NbRGLG2 and NbUBXN6,both interact with SRC7~(TN).In transient expression experiments,NbRGLG2 and NbUBXN6 were not resistant to SMV and TMV.However,when NbRGLG2 and NbUBXN6 are co-expressed with SRC7~(TN),both of them inhibit the antiviral activity of SRC7~(TN).When NbRGLG2 and NbUBXN6 gene were silenced in SRC7 overexpression(Ox-SRC7) plant,they can enhance the resistance of SRC7~(TN) to SMV and TMV.These results show that NbRGLG2 and NbUBXN6 negatively regulate the antiviral activity of SRC7.