Department of Integrative Plant Science, Chung-Ang University, Anseong 17456, Korea.
Department of Systems Biotechnology, Chung-Ang University, Anseong 17456, Korea.
Int J Mol Sci. 2018 Oct 5;19(10):3038. doi: 10.3390/ijms19103038.
To acclimate to different environments, gene expression has to be controlled using diverse transcriptional activators. FleQ activates σ-dependent transcription initiation and regulates flagellar biosynthesis and other mechanisms in several bacteria. pv. (), which is a causal agent of bacterial leaf blight on rice, lacking FleQ loses swimming motility and virulence is not altered. However, other biological mechanisms related with FleQ in are unknown. In this study, we generated the FleQ-overexpressing strain, (FleQ), and knockout mutant, . To predict the mechanisms affected by FleQ, label-free shotgun comparative proteomics was carried out. Based on proteomic results, we performed diverse phenotypic assays. (FleQ) had reduced ability to elicit disease symptoms and exopolysaccharide production. Additionally, the ability of (EV) (empty vector) and (FleQ) to form biofilm was decreased. Swarming motility of (EV) was abolished, but was only reduced for (FleQ). Additionally, abnormal twitching motility was observed in both strains. Siderophore production of (FleQ) was enhanced in iron-rich conditions. The proteomic and phenotypic analyses revealed that FleQ is involved in flagellar-dependent motility and other mechanisms, including symptom development, twitching motility, exopolysaccharide production, biofilm formation, and siderophore production. Thus, this study provides fundamental information about a σ-dependent transcription activator in .
为了适应不同的环境，基因表达必须使用不同的转录激活因子进行控制。FleQ 激活 σ 依赖性转录起始，并在几种细菌中调节鞭毛生物合成和其他机制。pv. (), 是水稻细菌性叶斑病的病原体，缺乏 FleQ 会丧失游泳运动能力，而毒力没有改变。然而，在 中与 FleQ 相关的其他生物学机制尚不清楚。在这项研究中，我们生成了 FleQ 过表达菌株 (FleQ) 和敲除突变体 ()。为了预测受 FleQ 影响的机制，我们进行了无标记 shotgun 比较蛋白质组学分析。基于蛋白质组学结果，我们进行了多种表型分析。(FleQ) 引发疾病症状和胞外多糖产生的能力降低。此外，(EV) (空载体) 和 (FleQ) 形成生物膜的能力降低。(EV) 的群集运动能力丧失，但 (FleQ) 的群集运动能力仅降低。此外，在这两种菌株中都观察到异常的扭动运动。(FleQ) 在富含铁的条件下增强了铁载体的产生。蛋白质组学和表型分析表明，FleQ 参与了鞭毛依赖性运动和其他机制，包括症状发展、扭动运动、胞外多糖产生、生物膜形成和铁载体产生。因此，本研究为 σ 依赖性转录激活因子在 中的作用提供了基础信息。
