prhKLM genes of Ralstonia solanacearum encode novel activators of hrp regulon and are required for pathogenesis in tomato.
prhKLM genes of Ralstonia solanacearum encode novel activators of hrp regulon and are required for pathogenesis in tomato.
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DOI：
10.1111/j.1574-6968.2011.02213.x
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发表时间：
2011-04
影响因子：
2.1
通讯作者：
Yong Zhang;A. Kiba;Y. Hikichi;K. Ohnishi
中科院分区：
文献类型：
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作者：
Yong Zhang;A. Kiba;Y. Hikichi;K. Ohnishi
青枯雷尔氏菌HRP调节子中的基因编码组成III型分泌系统的蛋白质。HRP调节子受HrpB正向调控，HrpG和PrhG共同激活hrpB的表达。我们已经鉴定出三个基因prhK、prhL和prhM，它们正向控制着OE1-1菌株中的HRP调节子。这些基因很可能形成一个操纵子，而这个操纵子在拉尔斯通属和伯克霍尔德里亚属中保存得很好。这表明操纵子不是植物病原菌所特有的。这三个基因中的每一个突变都取消了hrpB和prhG的表达。PrhK、prhL和prhM突变株对番茄完全丧失致病力，对烟草的致病力较弱。PrhK和PrhL与尿囊素水解酶有序列相似性，PrhM与羊肉有序列相似性。这表明这三种基因产物不是严格意义上的转录调节因子，而是间接调节HRP调节因子。这类新的毒力相关基因将标志着青枯病菌整体感染模式的新发现的开始。
The genes in the hrp regulon encode the proteins composing type III secretion system in Ralstonia solanacearum. The hrp regulon is positively controlled by HrpB, and hrpB expression is activated by both HrpG and PrhG. We have identified three genes, prhK, prhL, and prhM, which positively control the hrp regulon in strain OE1-1. These genes are likely to form an operon, and this operon is well conserved in the genera Ralstonia and Burkholderia. This indicates that the operon is not specific to the plant pathogens. Mutations in each of these three genes abolished hrpB and prhG expression. prhK, prhL, and prhM mutant strains lost pathogenicity toward tomato completely, and they were less virulent toward tobacco. PrhK and PrhL share sequence similarity with allophanate hydrolase and PrhM with LamB. This suggests that the three gene products are not transcriptional regulators in the strict sense, but regulate hrp regulon indirectly. This novel class of virulence-related genes will mark the beginning of new findings regarding the overall infection mode of R. solanacearum.