Disruption of comA homolog in Ralstonia solanacearum does not impair its twitching motility

Abstract

Ralstonia solanacearum is an important phyto-pathogenic bacterium. The bacterium exhibits type IV pili meditated twitching motility that has been implicated in the process of natural transformation in it. A comA gene homolog, alike in several other naturally competent bacteria, has been already reported in this bacterium. However, there are no report of direct link between comA and twitching motility during the natural transformation process in this pathogen. In order to figure out any connection between comA and twitching motility, we created an insertion mutation in comA gene homolog of R. solanacearum F1C1 strain. As anticipated, the insertion mutant (CBRS01 strain) was inefficient for natural transformation. CBRS01 strain was found to be proficient for twitching motility alike the wild-type F1C1. This is interesting since recent findings of Salzer et al. (2016;Environ Microbiol;18:65-74) showed deficiency of twitching motility due to comEC gene (comA homolog) mutation in another naturally competent Gram-negative bacterium Thermus thermophilus. Additionally, we also found CBRS01 strain to be proficient for extracellular cellulase activity and virulence on tomato seedlings. Our findings in this work indicate that an R. solanacearum strain inefficient in undergoing natural transformation can, however, be proficient in exhibiting twitching motility.

Novel mandelic acid derivatives suppress virulence of Ralstonia solanacearum via type III secretion system

“…These plates were stained with 0.1% Congo red for 15 min, washed with appropriate amount of distilled water, and then destained with 1 mol L −1 NaCl for 15 min. The diameter of the degradation circle was measured to determine the strength of cellulase activity 42 …”

“…The diameter of the degradation circle was measured to determine the strength of cellulase activity. 42…”