Mechanism of M60 family peptidase of Bacillus cereus AR156 involved in biocontrol against Meloidogyne incognita

Abstract:

[Background] Meloidogyne incognita has a wide range of hosts to infect including Solanaceae, Leguminosae, Cucurbitaceae and other vegetables. It causes serious damage and tens of billions of losses to the global agricultural production every year. Bacillus cereus AR156 is a gram-positive and rod-shaped bacterium that can be used as a biocontrol agent to control M. incognita, and has complete genome-wide sequencing. [Objective] In order to understand its biocontrol mechanism against M. incognita and to search for the related gene of biocontrol function, we analyzed the functional gene of B. cereus AR156. [Methods] We screened mortality of M. incognita and biocontrol efficiency under greenhouse in the AR156 miniTn10 random insertion transposon library to find mutants associated with biocontrol ability in AR156. Gene involved in biocontrol in AR156 was identified. And we compared producing-protease ability, colonization, biofilm formation and swarming motility. [Results] Compared with the AR156 wild-type, BC41 had reduced production of protease, colonization of plant rhizosphere, formation of biofilm and swarming motility. Its insertion site is the M60 family peptidase, which decreased the ability to biocontrol M. incognita. [Conclusion] M60 family peptidase plays an important role in the biocontrol activity of B. cereus AR156 by the analysis of biocontrol-related functional gene.