Surfactin, a quorum sensing signal molecule, globally affects the carbon metabolism in Bacillus amyloliquefaciens

Abstract

Surfactin, a quorum sensing signal molecule, is correlated with carbon metabolism in Bacillus amyloliquefaciens. In the present work, we found that mutation of srfA (ΔsrfA) led to an obviously changed carbon metabolism in B. amyloliquefaciens. Firstly, the PTS-glucose system was significantly increased as a feedback to glucose exhaustion. Secondly, the basic carbon metabolism such as glycolysis and TCA cycle was obviously weakened in ΔsrfA. Thirdly, the global regulator of CcpA (carbon catabolite protein A) and P ~ Ser46-HPr (seryl-phosphorylated form of histidine-containing protein) to mediate the CcpA-dependent CCR (carbon catabolite repression) were not increased, but the ability to use extracellular non- and less-preferred carbon sources was down-regulated in ΔsrfA. Fourthly, the carbon overflow metabolism such as biosynthesis of acetate was enhanced while biosynthesis of acetoin/2,3-butanediol and branched-chain amino acids were weakened in ΔsrfA. Finally, ΔsrfA could use most of non- and less-preferred carbon sources except for fatty acids, branched chain amino acids, and some organic acids (e.g. pyruvate, citrate and glutamate) after glucose exhaustion. Collectively, surfactin showed a global influence on carbon metabolism in B. amyloliquefaciens. Our studies highlighted a way to correlate quorum sensing with carbon metabolism via surfactin in Bacillus species.

Keywords

• Surfactin
• Carbon metabolism
• Quorum sensing
• CcpA
• HPr
• Bacillus amyloliquefaciens