Abstract :
[en] Streptomyces spp. and Bacillus velezensis are two soil-dwelling bacterial genera well known for the diversity of bioactive secondary metabolites (BSMs) they produce. Indeed, both bacteria are able to coproduce several non ribosomally synthesized (NR-)BSMs including cyclic lipopeptides (CLPs), polyketides, small oligopeptides, siderophores along with terpenes and ribosomally synthesized and post-translationally modified peptides (RiPPs). Those bacteria are known to adapt their metabolome in response to environmental cues such as signals emanating from bacteria, fungi or plants. However, little is known on the interaction between Bacillus and Streptomyces, though often encountered in the same environment.
Results from our work highlight promising metabolic outcomes from the interaction between these two genera. Indeed, Streptomyces appears to be able to enzymatically degrades Bacillus CLPs. Those CLPs are key for Bacillus competitive fitness. They exert antifungal activities and promote biofilm formation and motility, among others activities. Interestingly, this degradation does not affect all CLPs the same way. Indeed, iturin and surfactin can be promptly linearized and subsequently degraded in small peptides, while fengycin seems rather unaffected. The altered or different function that this degradation may do is still under investigations. Moreover, based on differential UPLC/MS-based metabolomics, it appears that upon perception of Bacillus, Streptomyces specifically modulates its production of BSMs. We observed an increased or lowered production of BSMs, the accumulation of variants of known compounds and the stimulation of unidentified metabolites which is particularly interesting since Streptomyces genomes encode many cryptic biosynthetic gene clusters BGC
