Abstract
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 PerRwere 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 .
Keywords: Bacillus amyloliquefaciens , redox, surfactin,
biofilm, Spx, PerR.