PXO_RS20535, Encoding a Novel Response Regulator, Is Required for Chemotactic Motility, Biofilm Formation, and Tolerance to Oxidative Stress in Xanthomonas oryzae pv. oryzae

Abstract

Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight of rice, possesses two-component regulatory systems (TCSs) as an intracellular signaling pathway. In this study, we observed changes in virulence, biofilm formation, motility, chemotaxis, and tolerance against oxidative stress of a knockout mutant strain for the PXO_RS20535 gene, encoding an orphan response regulator (RR). The mutant strain lost virulence, produced significantly less biofilm, and showed remarkably reduced motility in swimming, swarming, and twitching. Furthermore, the mutant strain lost glucose-guided movement and showed clear diminution of growth and survival in the presence of H2O2. These results indicate that the RR protein encoded in the PXO_RS20535 gene (or a TCS mediated by the protein) is closely involved in regulation of biofilm formation, all types of motility, chemotaxis, and tolerance against reactive oxygen species (ROS) in Xoo. Moreover we found that the expression of most genes required for a type six secretion system (T6SS) was decreased in the mutant, suggesting that lack of the RR gene most likely leads to defect of T6SS in Xoo.

LC_Glucose-Inhibited Division Protein Is Required for Motility, Biofilm Formation, and Stress Response in Lysobacter capsici X2-3

“…This result is in agreement with previous reports in S. mutans in which the gidA mutant showed a reduced ability to withstand stress conditions ( Li et al, 2014 ). Moreover, in Xanthomonas oryzae , the PXO_RS20535 mutant produced significantly less biofilm and had a clear diminution of growth and survival under stress conditions ( Antar et al, 2020 ). These results indicated that biofilm formation may be involved in the growth of X2-3 in various stressful environments.…”

Elevation of Fatty Acid Biosynthesis Metabolism Contributes to Zhongshengmycin Resistance in Xanthomonas oryzae

“…Drug-resistant bacteria can provide protection for other more vulnerable bacteria through the secondary metabolite indole so as to improve the survival ability of the whole population in stressful environments [28]. The existing research on X. oryzae is mainly focused on the effects that biological agents, nano agents, and gene knockout have on its virulence and control [8,[29][30][31]; however, studies concerning the mechanism of drug resistance of X. oryzae from the perspective of metabolomics are lacking.…”

Allicin‐inspired disulfide derivatives containing quinazolin‐4(3H)‐one as a bacteriostat against Xanthomonas oryzae pv. oryzae

“…In order to observe the swimming movement of the Xoo colonies, the different concentrations of compound 1 and 2 μL bacterial solutions (OD 595 ≈ 0.1) were co‐inoculated in NA medium containing 0.3% agar and cultured for 3–5 days. Crystal Violet staining 47 and tube puncture 48 were carried out with a toothpick in a Petri dish and inoculation needle in a tube (NA medium containing 1% agar and compound 1 ) to evaluate the twitching motility movement of bacteria.…”