Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang 550025, China.
Kiwifruit Engineering & Technology Research Center, Guizhou University, Guiyang 550025, China.
Int J Mol Sci. 2022 Oct 14;23(20):12306. doi: 10.3390/ijms232012306.
Bacterial canker of kiwifruit is a devastating disease caused by pv. (). The type III secretion system (T3SS), which translocates effectors into plant cells to subvert plant immunity and promote extracellular bacterial growth, is required for virulence. Despite that the "HrpR/S-HrpL" cascade that sophisticatedly regulates the expression of T3SS and effectors has been well documented, the transcriptional regulators of remain to be determined. In this study, the OmpR-like transcription factor, previously identified by DNA pull-down assay, was found to be involved in the regulation of genes, and its regulatory mechanisms and other functions in were explored through techniques including gene knockout and overexpression, ChIP-seq, and RNA-seq. The OmpR-like transcription factor had binding sites in the promoter region of the , and the transcriptional level of the increased after the deletion of and decreased upon its overexpression in an deletion background. Additionally, overexpression reduced the strain's capacity to form biofilms and lipopolysaccharides, led to its slow growth in King's B medium, and reduced its swimming ability, although there was no significant effect on its pathogenicity against kiwifruit hosts. Our results indicated that OmpR-like directly and negatively regulates the transcription of and may be involved in the regulation of multiple biological processes in . Our results provide a basis for further understanding the transcriptional regulation mechanism of in .
猕猴桃溃疡病菌是一种毁灭性疾病，由 pv. ()引起。III 型分泌系统（T3SS）是一种将效应物转运到植物细胞中以颠覆植物免疫并促进细胞外细菌生长的系统，对于细菌的毒力是必需的。尽管已经充分证明了精巧地调节 T3SS 和效应物表达的“HrpR/S-HrpL”级联反应，但 的转录调节剂仍有待确定。在这项研究中，通过 DNA 下拉测定先前鉴定的 OmpR 样转录因子被发现参与 基因的调控，并通过基因敲除和过表达、ChIP-seq 和 RNA-seq 等技术探索了其在 中的调控机制和其他功能。OmpR 样转录因子在 的启动子区域具有结合位点，并且在 缺失后， 的转录水平增加，而在缺失背景下过表达时则降低。此外， 的过表达降低了该菌株形成生物膜和脂多糖的能力，导致其在 King's B 培养基中生长缓慢，并降低了其游泳能力，尽管对其猕猴桃宿主的致病性没有显著影响。我们的结果表明，OmpR 样直接负调控 的转录，可能参与 中多个生物学过程的调节。我们的结果为进一步了解 在 中的转录调控机制提供了基础。
