RDR6 has a broad-spectrum but temperature-dependent antiviral defense role in Nicotiana benthamiana
RDR6 has a broad-spectrum but temperature-dependent antiviral defense role in Nicotiana benthamiana
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DOI：
10.1128/jvi.79.24.15209-15217.2005
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发表时间：
2005-12-01
影响因子：
5.4
通讯作者：
Morris, TJ
中科院分区：
文献类型：
--
作者：
Qu, F;Ye, XH;Morris, TJ
SDE1/SGS2/RDR6是一种来自拟南芥（Arabidopsis thaliana）的RNA依赖性RNA聚合酶（RNA-dependent RNA polymerase, RdRP），先前已被发现在维持转基因转录后沉默中不可或缺，但在抗病毒防御中似乎是多余的。为了阐明该RdRP在不同寄主植物中的抗病毒作用，并评估植物生长条件是否影响其作用，我们下调了本烟同源物NbRDR6的表达，并检测了植物在不同生长温度下对各种病毒的易感性的变化。我们在这里描述的结果清楚地表明，NbRDR6表达降低的植物对所有测试的病毒都更敏感，并且这种影响在较高的生长温度下更为明显。NbRDR6的表达减少也使烟草花叶病毒在茎尖上高效增殖，导致microrna介导的发育调控严重中断。基于这些结果，我们提出NbRDR6参与抗病毒RNA沉默途径，该途径受温度升高刺激，但被病毒编码的沉默抑制因子抑制。这两个因素的相对优势，以及其他植物防御成分，严重影响病毒感染的结果。
SDE1/SGS2/RDR6, a putative RNA-dependent RNA polymerase (RdRP) from Arabidopsis thaliana, has previously been found to be indispensable for maintaining the posttranscriptional silencing of transgenes, but it is seemingly redundant for antiviral defense. To elucidate the antiviral role of this RdRP in a different host plant and to evaluate whether plant growth conditions affect its role, we down-regulated expression of the Nicotiana benthamiana homolog, NbRDR6, and examined the plants for altered susceptibility to various viruses at different growth temperatures. The results we describe here clearly show that plants with reduced expression of NbRDR6 were more susceptible to all viruses tested and that this effect was more pronounced at higher growth temperatures. Diminished expression of NbRDR6 also permitted efficient multiplication of tobacco mosaic virus in the shoot apices, leading to serious disruption with microRNA-mediated developmental regulation. Based on these results, we propose that NbRDR6 participates in the antiviral RNA silencing pathway that is stimulated by rising temperatures but suppressed by virus-encoded silencing suppressors. The relative strengths of these two factors, along with other plant defense components, critically influence the outcome of virus infections.