Bacterial communication intelligently regulates their interactions in anammox consortia under decreasing temperatures

Bacterial communication could affect their interactions, but whether this regulation has "intelligence" is still unknown. Here, we operated an anammox reactor under temperature gradient from 35 °C to 15 °C. As results, expression abundance of bacterial communication genes increased by 12 % significantly after temperature declined. Division of labor among distinct signal molecules was evidenced by complementary roles of acyl-homoserine lactones (AHLs) and diffusible signal factor (DSF) in affecting bacterial interactions and niche differentiation respectively. DSF based inter-and intra-communication helped bacteria match their investments and rewards during cross-feedings. When temperature was below 25 °C, transcription regulator Clp governed by DSF inclined to promote folate and molybdenum cofactor biosynthesis, which coincidentally benefited one anammox species more than another. Meanwhile, for the anammox species with lower benefits, Clp also inclined to decrease biosynthesis of costly tryptophan and vitamin B1 rewarding others. Interestingly, bacterial communication inclined to influence the bacteria with many cooperators in the community or with high capacity to export cofactors for cross-feedings when temperature decreased. As results, these bacteria were enriched which could lead to closer interactions in whole community to adapt to low temperatures. The discovered intelligence of bacterial communication opened another window for understanding bacterial sociobiology.