Virus resistance induced by NB-LRR proteins involves Argonaute4-dependent translational control
Virus resistance induced by NB-LRR proteins involves Argonaute4-dependent translational control
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DOI：
10.1111/j.1365-313x.2009.03832.x
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发表时间：
2009-06-01
期刊：
影响因子：
7.2
通讯作者：
Moffett, Peter
中科院分区：
文献类型：
--
作者：
Bhattacharjee, Saikat;Zamora, Alejandro;Moffett, Peter
植物抗病基因是植物对病毒的主动抗性基因，它编码的蛋白质具有核苷酸结合（NB）和富含亮氨酸重复序列（LRR）结构域。在识别病原体衍生的激发子后，这些NB-LRR蛋白被认为启动导致病原体限制的许多信号传导途径。然而，人们对最终减少病毒积累的分子机制知之甚少。在这里，我们表明，植物NB-LRR蛋白与其同源激发子的共表达导致抗病毒反应，抑制本氏烟草中病毒编码蛋白的翻译。这种抗病毒反应依赖于病毒顺式元件，并且在NB-LRR蛋白活化后，病毒转录物积累但不与核糖体缔合。Argonaute 4样基因的下调损害了对病毒转录物翻译的诱导抑制和NB-LRR介导的病毒抗性。Argonaute蛋白参与小RNA介导的RNA降解，并参与非降解依赖性翻译控制。我们的研究结果表明，Argonaute蛋白参与病毒转录本的特异性翻译控制是NB-LRR蛋白介导的病毒抗性的关键因素。
P>Active resistance to viruses is afforded by plant disease resistance (R) genes, which encode proteins with nucleotide-binding (NB) and leucine-rich repeat (LRR) domains. Upon recognition of pathogen-derived elicitors, these NB-LRR proteins are thought to initiate a number of signaling pathways that lead to pathogen restriction. However, little is known about the molecular mechanisms that ultimately curtail virus accumulation. Here, we show that the co-expression of a plant NB-LRR protein with its cognate elicitor results in an antiviral response that inhibits the translation of virus-encoded proteins in Nicotiana benthamiana. This antiviral response is dependent on viral cis elements, and, upon activation of the NB-LRR protein, viral transcripts accumulate but do not associate with ribosomes. The induced inhibition of viral transcript translation and NB-LRR-mediated virus resistance were compromised by the downregulation of Argonaute4-like genes. Argonaute proteins have been implicated in small RNA-mediated RNA degradation, and in degradation-independent translational control. Our results suggest that the engagement of Argonaute proteins in the specific translational control of viral transcripts is a key factor in virus resistance mediated by NB-LRR proteins.