Open AccessThe RavA/VemR two‐component system plays vital regulatory roles in the motility and virulence of Xanthomonas campestris
Author(s) -
Lin Maojuan,
Wu Kejian,
Zhan Zhaohong,
Mi Duo,
Xia Yingying,
Niu Xiaolei,
Feng Shipeng,
Chen Yinhua,
He Chaozu,
Tao Jun,
Li Chunxia
Publication year - 2022
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.13164
Subject(s) - biology , virulence , xanthomonas campestris , xanthomonas campestris pv. campestris , genetics , gene , rpon , microbiology and biotechnology , operon , motility , response regulator , histidine kinase , mutant , gene expression , promoter
Abstract Xanthomonas campestris pv. campestris (Xcc) can cause black rot in cruciferous plants worldwide. Two‐component systems (TCSs) are key for bacterial adaptation to various environments, including hosts. VemR is a TCS response regulator and crucial for Xcc motility and virulence. Here, we report that RavA is the cognate histidine kinase (HK) of VemR and elucidate the signalling pathway by which VemR regulates Xcc motility and virulence. Genetic analysis showed that VemR is epistatic to RavA. Using bacterial two‐hybrid experiments and pull‐down and phosphorylation assays, we found that RavA can interact with and phosphorylate VemR, suggesting that RavA is the cognate HK of VemR. In addition, we found that RpoN2 and FleQ are epistatic to VemR in regulating bacterial motility and virulence. In vivo and in vitro experiments demonstrated that VemR interacts with FleQ but not with RpoN2. RavA/VemR regulates the expression of the flagellin‐encoding gene fliC by activating the transcription of the rpoN2‐vemR‐fleQ and flhF ‐ fleN ‐ fliA operons. In summary, our data show that the RavA/VemR TCS regulates FleQ activity and thus influences the expression of motility‐related genes, thereby affecting Xcc motility and virulence. The identification of this novel signalling pathway will deepen our understanding of Xcc–plant interactions.