Mutation of praR in Rhizobium leguminosarum enhances root biofilms, improving nodulation competitiveness by increased expression of attachment proteins.
Mutation of praR in Rhizobium leguminosarum enhances root biofilms, improving nodulation competitiveness by increased expression of attachment proteins.
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DOI：
10.1111/mmi.12670
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发表时间：
2014-08
影响因子：
3.6
通讯作者：
Downie JA
中科院分区：
文献类型：
--
作者：
Frederix M;Edwards A;Swiderska A;Stanger A;Karunakaran R;Williams A;Abbruscato P;Sanchez-Contreras M;Poole PS;Downie JA
在豆科根瘤菌Bv.在Viciae中，群体感应受CinR调控，CinR诱导CinIS操纵子。CINI合成AHL，而CINS失活抑制因子PraR。PraR基因突变增强生物被膜的体外研究我们开发了一种依赖于光(Lux)的根瘤菌与根附着的测试方法，并证明了PraR的突变增加了豌豆根上的生物膜。在混合接种中，prR突变体对豌豆根瘤的侵染优于野生型。基因芯片和启动子融合分析表明，PraR抑制自身的转录，而PraR的突变增加了几个基因的表达，包括分泌蛋白(粘附素RapA2、RapB和RAPC、两个钙粘附素和聚糖酶PlyB)、多糖调节因子RosR和另一种类似于PraR的蛋白。PraR与这些基因中的几个启动子结合，表明直接抑制。RapA2、RapB、RAPC、plyB、钙粘蛋白或rosR的突变不影响PraR突变体增强的根附着或根瘤竞争能力。然而，RAPA、RAPB和RAPC的突变组合消除了增强的依附性和根瘤竞争力。我们的结论是，解除PraR介导的抑制决定了一种生活方式的转变，允许表达对根部生物膜形成和随后豆科植物根部侵染起重要作用的基因。
In Rhizobium leguminosarum bv. viciae, quorum-sensing is regulated by CinR, which induces the cinIS operon. CinI synthesizes an AHL, whereas CinS inactivates PraR, a repressor. Mutation of praR enhanced biofilms in vitro. We developed a light (lux)-dependent assay of rhizobial attachment to roots and demonstrated that mutation of praR increased biofilms on pea roots. The praR mutant out-competed wild-type for infection of pea nodules in mixed inoculations. Analysis of gene expression by microarrays and promoter fusions revealed that PraR represses its own transcription and mutation of praR increased expression of several genes including those encoding secreted proteins (the adhesins RapA2, RapB and RapC, two cadherins and the glycanase PlyB), the polysaccharide regulator RosR, and another protein similar to PraR. PraR bound to the promoters of several of these genes indicating direct repression. Mutations in rapA2, rapB, rapC, plyB, the cadherins or rosR did not affect the enhanced root attachment or nodule competitiveness of the praR mutant. However combinations of mutations in rapA, rapB and rapC abolished the enhanced attachment and nodule competitiveness. We conclude that relief of PraR-mediated repression determines a lifestyle switch allowing the expression of genes that are important for biofilm formation on roots and the subsequent initiation of infection of legume roots.
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影响因子：
4.8
作者：
Abdian, Patricia L.;Caramelo, Julio J.;Zorreguieta, Angeles
通讯作者：
Zorreguieta, Angeles
影响因子：
3.2
作者：
Karunakaran, R.;Ramachandran, V. K.;Poole, P. S.
通讯作者：
Poole, P. S.
影响因子：
3.2
作者：
Edwards, Anne;Frederix, Marijke;Downie, J. Allan
通讯作者：
Downie, J. Allan
影响因子：
3.6
作者：
Kearns, DB;Chu, F;Losick, R
通讯作者：
Losick, R
影响因子：
4.4
作者：
Krehenbrink, Martin;Downie, J. Allan
通讯作者：
Downie, J. Allan