Inhibition of biofilm formation by Cd2+ on Bacillus subtilis 1JN2 depressed its biocontrol efficiency against Ralstonia wilt on tomato

Publication date: October 2018Source: Microbiological Research, Volume 215Author(s): Wei Yang, Haixia Yan, Ji Zhang, Yuming Gao, Wei Xu, Jinshan Shang, Yuming LuoAbstractBacillus subtilis 1JN2 can serve as an effective biocontrol agent against Ralstonia wilt on tomato, but the efficiency of control depends on the levels of heavy metals in the rhizosphere soil. Here, we investigated how the heavy metal Cd2+ affects the biocontrol efficacy of B.subtilis 1JN2 on Ralstonia wilt. We found that low Cd2+ content of 2 mM or lower had no effects on the biofilm formation of 1JN2, while media containing 3 mM or higher Cd2+ levels inhibited biofilm formation. Interestingly, high concentration of Cd2+ (5 mM) showed inhibition of B.subtilis 1JN2 cell growth. We next tested the effects of Cd2+ on the colonization of 1JN2 by supplementing artificial Cd2+ in the tomato rhizosphere in a greenhouse setting. We found that 3 mM Cd2+ in the tomato rhizosphere inhibited the colonization of B.subtilis 1JN2, Only 103 CFU/mL 1JN2 was detected one week post treated with 107 CFU/mL but 105 CFU/mL could be detected without Cd2+ in the soil. The presence of Cd2+ had no effect on the colonization of Ralstonia solanacearum on tomato, but the biocontrol efficacy against Ralstonia wilt by 1JN2 decreased 54.2% when the soil contained 3 mM Cd2+ compared to the control without Cd2+. Taken together, we found that the failure of biofilm formation of Bacillus subtilis 1JN2 that affected by Cd2+ lead...
Source: Microbiological Research - Category: Infectious Diseases Source Type: research