State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
FEMS Microbiol Lett. 2010 Mar;304(1):20-8. doi: 10.1111/j.1574-6968.2010.01892.x. Epub 2010 Jan 15.
Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot disease in cruciferous plants. The synthesis of known virulence factors in this organism, such as extracellular enzymes and biofilm, is strictly regulated in response to environmental stimuli. Two-component signal transduction systems sense environmental signals and alter bacterial behavior by regulating gene expression. Here, we identified a response regulator, VemR, that regulates Xcc pathogenesis. The vemR gene encodes an atypical response regulator that only contains a receiver domain. Deletion of vemR resulted in decreased virulence, exopolysaccharide production and motility of Xcc. The vemR gene is located in an operon flanked by genes fleQ and rpoN2. Genetic analysis indicated that deletion of fleQ does not affect motility significantly. However, a double mutant DeltavemR/DeltafleQ reversed the phenotype of DeltavemR, indicating that fleQ is epistatic to vemR in the regulation of virulence and adaptation.
野油菜黄单胞菌野油菜致病变种（Xcc）是十字花科植物黑腐病的致病菌。该菌中已知毒力因子（如胞外酶和生物膜）的合成受到严格调控以响应环境刺激。双组分信号转导系统可感知环境信号，并通过调节基因表达来改变细菌行为。在此，我们鉴定了一个响应调节子 VemR，它可调节 Xcc 的致病性。vemR 基因编码一个仅包含受体结构域的非典型响应调节子。vemR 缺失导致 Xcc 的毒力、胞外多糖产生和运动性降低。vemR 基因位于 fleQ 和 rpoN2 基因侧翼的操纵子中。遗传分析表明，fleQ 缺失对运动性没有显著影响。然而，vemR 和 fleQ 的双缺失突变体 DeltavemR/DeltafleQ 逆转了 DeltavemR 的表型，表明在毒力和适应性调节方面 fleQ 对 vemR 是上位的。
