Anti-viral mechanisms induced by the plant immune system / Les mécanismes anti-viraux induits par le système immunitaire végétal

植物免疫系统诱导的抗病毒机制 / Les mécanismes anti-viraux induits par le système immunitaire végétal

基本信息

批准号：
386223-2010
负责人：
Moffett, Peter
金额：
$ 5.17万
依托单位：
Université de Sherbrooke
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2015
资助国家：
加拿大
起止时间：
2015-01-01 至 2016-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=572927
关键词：
Anti viral mechanisms induced plant

项目摘要

We study the molecular mechanisms by which plants defend themselves against pathogens in general, and viruses in particular. One of the main defences against plant viruses is based on targeting the RNA genetic material of the virus. A mechanism broadly known as RNA silencing exists in all eukaryotes that recognizes double-stranded RNAs and is responsible for regulating multiple biological processes, including virus resistance by targeting viral double-stranded RNA for degradation. Dicer proteins process double-stranded RNAs into defined small RNAs and these in turn are incorporated into "slicer" complexes which target any RNAs with complementarity to the small RNA. The active components of slicer complexes are a family of endoribonucleases known as Argonaute (AGO) proteins. Higher plant genomes encode at least ten AGO proteins, which are involved in a variety of RNA silencing-related phenomenon, and some of these have been implicated in constitutive anti-viral defences. In turn, plant viruses have evolved suppressors of RNA silencing to overcome this constitutive defence. However, in addition to RNA silencing, plants encode immune receptor-like proteins (NB-LRR proteins) that recognize all types of pathogens and induce a dramatic suite of defence responses. We have found that NB-LRR proteins engage certain AGO proteins to occlude viral RNAs from translating protein, hence stopping the virus from spreading. However, this process appears to use different AGOs family members than those involved in constitutive anti-viral responses. We will identify which AGO family members are responsible for both constitutive and induced anti-viral responses and we will characterize how these proteins affect the translation of viral RNA transcripts using a variety of plant model systems, genetics, biochemistry, cell and molecular biology. In addition we will identify cellular proteins that interact with NB-LRR proteins in order to gain more insight into how induced anti-viral responses are initiated.

我们研究植物防御一般病原体，特别是病毒的分子机制。针对植物病毒的主要防御措施之一是针对病毒的 RNA 遗传物质。所有真核生物中都存在一种被广泛称为 RNA 沉默的机制，该机制可识别双链 RNA，并负责调节多种生物过程，包括通过靶向病毒双链 RNA 进行降解来实现病毒抗性。 Dicer 蛋白将双链 RNA 加工成特定的小 RNA，然后这些小 RNA 又被整合到“切片器”复合物中，该复合物以与小 RNA 互补的任何 RNA 为目标。切片复合物的活性成分是核糖核酸内切酶家族，称为 Argonaute (AGO) 蛋白。高等植物基因组编码至少十种 AGO 蛋白，这些蛋白参与多种 RNA 沉默相关现象，其中一些与组成型抗病毒防御有关。反过来，植物病毒进化出了RNA沉默的抑制子来克服这种组成性防御。然而，除了 RNA 沉默之外，植物还编码免疫受体样蛋白（NB-LRR 蛋白），可以识别所有类型的病原体并诱导一系列引人注目的防御反应。我们发现 NB-LRR 蛋白与某些 AGO 蛋白结合，阻止病毒 RNA 翻译蛋白，从而阻止病毒传播。然而，这个过程似乎使用了与组成型抗病毒反应相关的不同 AGO 家族成员。我们将确定哪些 AGO 家族成员负责组成型和诱导型抗病毒反应，并且我们将使用各种植物模型系统、遗传学、生物化学、细胞和分子生物学来描述这些蛋白质如何影响病毒 RNA 转录本的翻译。此外，我们将鉴定与 NB-LRR 蛋白相互作用的细胞蛋白，以便更深入地了解诱导的抗病毒反应是如何启动的。