Dunoyer Patrice, Himber Christophe, Voinnet Olivier
CNRS UPR2357, IBMP, Strasbourg, France.
Nat Genet. 2006 Feb;38(2):258-63. doi: 10.1038/ng1722. Epub 2006 Jan 22.
Regulation of gene expression through microRNAs (miRNAs) and antiviral defense through small interfering RNAs (siRNAs) are aspects of RNA silencing, a process originally discovered as an unintended consequence of plant transformation by disarmed Agrobacterium tumefaciens strains. Although RNA silencing protects cells against foreign genetic elements, its defensive role against virulent, tumor-inducing bacteria has remained unexplored. Here, we show that siRNAs corresponding to transferred-DNA oncogenes initially accumulate in virulent A. tumefaciens-infected tissues and that RNA interference-deficient plants are hypersusceptible to the pathogen. Successful infection relies on a potent antisilencing state established in tumors whereby siRNA synthesis is specifically inhibited. This inhibition has only modest side effects on the miRNA pathway, shown here to be essential for disease development. The similarities and specificities of the A. tumefaciens RNA silencing interaction are discussed and contrasted with the situation encountered with plant viruses.
通过微小RNA（miRNA）对基因表达的调控以及通过小干扰RNA（siRNA）进行的抗病毒防御是RNA沉默的两个方面，RNA沉默这一过程最初是作为无致病力的根癌土壤杆菌菌株进行植物转化时的意外结果而被发现的。尽管RNA沉默可保护细胞免受外来遗传元件的影响，但其对致病的、致瘤细菌的防御作用仍未得到探索。在此，我们表明，与转移DNA致癌基因相对应的siRNA最初在被致病力强的根癌土壤杆菌感染的组织中积累，并且RNA干扰缺陷型植物对该病原体高度敏感。成功的感染依赖于肿瘤中建立的一种有效的抗沉默状态，在此状态下，siRNA的合成被特异性抑制。这种抑制对miRNA途径只有适度的副作用，本文表明miRNA途径对疾病发展至关重要。我们讨论了根癌土壤杆菌RNA沉默相互作用的相似性和特异性，并将其与植物病毒的情况进行了对比。
