Transcriptional rewiring and spatiotemporal expression of evolutionarily conserved redox active molecules during bacterial community morphogenesis (973.4)

Biofilm formation by microbes is an adaptive feature common to several microorganisms, wherein community of cells is known to reconstruct a multicellular lifestyle. Such architecture results in the formation of distinct metabolic zones that are demarcated by oxygen gradients and heterogeneous cell population adapted to its microenvironment. While the quest for metabolites that would make these oxygen‐deficient zones habitable has been recognized, phenazines from Pseudomonas aeruginosa are the only characterized intracellular alternate electron acceptors to oxygen. In this study we report identification of an evolutionarily conserved biosynthetic cluster that produces redox‐active molecules ‐ bifilmoquinones and bifilmopyrones, specifically during biofilm development. Remarkably, about half of the Mycobacterium smegmatis transcriptome rewires to produce this multicellular ensemble and the hypoxia‐induced altered intracellular redox state appears to be the crucial trigger dictating this process of morphogenesis. Our analysis suggests the spatiotemporal expression of the biosynthetic cluster a way to acquire an alternate mode of respiration to survive in biofilm core. We further corroborate expression of these redox‐active molecules in the floating biofilms of Bacillus subtilis. Recognition of this novel adaptive redox‐balancing mechanism across several bacterial systems resolves the long‐standing issue of bacterial adaptability to oxygen‐depleted niches.