Surfactin facilitates the establishment of Bacillus subtilis in synthetic communities

Abstract

Soil bacteria are prolific producers of a myriad of biologically active secondary metabolites. These natural products play key roles in modern society, finding use as anti-cancer agents, as food additives, and as alternatives to chemical pesticides. As for their original role in interbacterial communication, secondary metabolites have been extensively studied under in vitro conditions, revealing a multitude of roles including antagonism, effects on motility, niche colonization, signaling, and cellular differentiation. Despite the growing body of knowledge on their mode of action, biosynthesis, and regulation, we still do not fully understand the role of secondary metabolites on the ecology of the producers and resident communities in situ. Here, we specifically examine the influence of Bacillus subtilis-produced cyclic lipopeptides (LPs) during the assembly of a bacterial synthetic community (SynCom), and simultaneously, explore the impact of LPs on B. subtilis establishment success in a SynCom propagated in an artificial soil microcosm. We found that surfactin production facilitates B. subtilis establishment success within multiple SynComs. Surprisingly, while neither a wild type nor a LP non-producer mutant had major impact on the SynCom composition over time, the B. subtilis and the SynCom metabolomes are both altered during co-cultivation. Overall, our work demonstrates the importance of surfactin production in microbial communities, suggesting a broad spectrum of action of this natural product.