CodY, ComA, DegU and Spo0A Controlling Lipopeptides Biosynthesis in
Bacillus amyloliquefaciens fmbJ
Abstract
Bacillus amyloliquefaciens, as a biocontrol bacterium, mainly produces
secondary metabolites to resist pathogenic microorganisms. In the study,
B. amyloliquefaciens fmbJ could produce several antimicrobial
lipopeptides (bacillomycin D, surfactin, and fengycin). In order to
clarify the influence of transcriptional regulatory genes (codY, comA,
degU, and spo0A) regulating the biosynthesis of lipopeptides, especially
bacillomycin D, these genes in fmbJ were knocked out. The results showed
that the productions of bacillomycin D were significantly reduced
compared with that of fmbJ. The changes of lipopetides production in
fmbJ with the genes deleted were then analyzed by comparative
transcriptomics. Their deletion induced great changes in the levels of
transcripts specifying metabolic pathways, quorum sensing system and
substance transport system in fmbJ. Moreover, overexpression of these
genes improved the productions of bacillomycin D. In particular, the
overexpression of spo0A enhanced bacillomycin D yield up to 648.9 ± 60.9
mg/L from 277.3 ± 30.5 mg/L. On the contrary, the yields of surfactin in
fmbJΔcodY and fmbJΔdegU were significantly improved. And, the regulatory
factor CodY had no significant effect on the synthesis of fengycin. In
addition, it was found that CodY had a concentration dependence on
bacillomycin D synthesis. This study indicated the direction of genetic
manipulation to improve the yields of antimicrobial lipopeptides and
laid a theoretical foundation for the industrial production of
lipopeptides.