Cellular redox state affects biofilm formation by a surfactin -dependent
manner in Bacillus amyloliquefaciens?
Surfactin is a signal to trigger biofilm formation against harsh
environments. Generally, harsh environments can result in change of the
cellular redox state to induce biofilm formation, but we know little
about whether the cellular redox state influences biofilm formation via
surfactin. Here, the reductant glucose could reduce surfactin and
enhance biofilm formation by a surfactin-independent way. The oxidant
H2O2 led to a decrease of surfactin accompanying with weakened biofilm
formation. Spx and PerR were both necessary for surfactin production and
biofilm formation. H2O2 improved surfactin production but inhibited
biofilm formation by a surfactin-independent manner in Δspx, while it
reduced surfactin production without obvious influence on biofilm
formation in ΔperR. The ability against H2O2 stress was enhanced in
Δspx, but weakened in ΔperR. Thereby, PerR was favorable for resisting
oxidative stress, while Spx played a negative role in this action.
Knockout and compensation of rex also supported that the cells could
form biofilm by a surfactin-independent way. Collectively, surfactin is
not a unique signal to trigger biofilm formation, and the cellular redox
state can influence biofilm formation by a surfactin- dependent or
independent way in B. amyloliquefaciens.