The RpoN2-PilRX regulatory system governs type IV pilus gene transcription and is required for bacterial motility and virulence in Xanthomonas oryzae pv. oryzae.
The RpoN2-PilRX regulatory system governs type IV pilus gene transcription and is required for bacterial motility and virulence in Xanthomonas oryzae pv. oryzae.
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RpoN2-PilRX 调控系统控制 IV 型菌毛基因转录，并且是米黄单胞菌 (Xanthomonas oryzae pv.) 细菌运动和毒力所必需的。
DOI：
10.1111/mpp.12920
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Chen Huamin
中科院分区：
文献类型：
--
作者：
Yu Chao;Nguyen Doan-Phuong;Ren Zhaoyu;Liu Jianan;Yang Fenghuan;Tian Fang;Fan Susu;Chen Huamin
IV型菌毛（T4 P）是一类特殊的细菌表面丝状体，在病原菌的表面粘附、运动、生物膜形成和毒力中起着至关重要的作用。然而，水稻白叶枯病病原菌Xanthomonasoryzaepv. candy（Xoo）中T4 P的调控机制及其与细菌毒力的关系尚不清楚。我们以前的研究表明，σ 54因子RpoN 2以鞭毛非依赖的方式调节细菌对水稻的毒性。在这项研究中，酵母双杂交和下拉试验都显示RpoN 2直接特异性地与PilRX相互作用，PilRX是菌毛基因簇中双组分系统PilS-PilR的反应调节因子PilR的同源物。基因组序列和逆转录PCR（RT-PCR）分析显示，13个调控子包含25个编码T4 P结构组分和推定调节子的基因。在大多数T4 P基因转录单位的启动子序列中鉴定出共有RpoN 2结合序列GGN 10 GC。电泳迁移率变动分析证实了RpoN 2与主要菌毛蛋白genepilAX、内膜平台蛋白genepilCX和pilRX的启动子的直接结合。启动子活性和定量RT-PCR分析证明了T4 P基因的RpoN 2的直接和间接转录调控。此外，pilAX、pilCX和pilRX的个别缺失导致水稻中的抽搐和游泳运动性、生物膜形成和毒性显著降低。总之，当前研究的结果表明，RpoN 2 ‐PilRX调节系统通过调节Xoo中的T4 P基因转录来控制细菌运动性和毒力。
The type IV pilus (T4P), a special class of bacterial surface filament, plays crucial roles in surface adhesion, motility, biofilm formation, and virulence in pathogenic bacteria. However, the regulatory mechanism of T4P and its relationship to bacterial virulence are still little understood inXanthomonas oryzaepv.oryzae(Xoo), the causal pathogen of bacterial blight of rice. Our previous studies showed that the σ54factor RpoN2 regulated bacterial virulence on rice in a flagellum‐independent manner in Xoo. In this study, both yeast two‐hybrid and pull‐down assays revealed that RpoN2 directly and specifically interacted with PilRX, a homolog of the response regulator PilR of the two‐component system PilS‐PilR in the pilus gene cluster. Genomic sequence and reverse transcription PCR (RT‐PCR) analysis showed 13 regulons containing 25 genes encoding T4P structural components and putative regulators. A consensus RpoN2‐binding sequence GGN10GC was identified in the promoter sequences of most T4P gene transcriptional units. Electrophoretic mobility shift assays confirmed the direct binding of RpoN2 to the promoter of the major pilin genepilAX, the inner membrane platform protein genepilCX, andpilRX. Promoter activity and quantitative RT‐PCR assays demonstrated direct and indirect transcriptional regulation by RpoN2 of the T4P genes. In addition, individual deletions ofpilAX,pilCX, andpilRXresulted in significantly reduced twitching and swimming motility, biofilm formation, and virulence in rice. Taken together, the findings from the current study suggest that the RpoN2‐PilRX regulatory system controls bacterial motility and virulence by regulating T4P gene transcription in Xoo.