Project description:We compared the global transcriptomic analysis of Desulfoluna spongiiphila strain AA1, an organohalide-respiring Desulfobacterota isolated from a marine sponge, with 2,6-dibromophenol or with sulfate as electron acceptor. The most significant difference of the transcriptomic analysis was the expression of one reductive dehalogenase gene cluster (rdh16), which was significantly upregulated with 2,6-dibromophenol.
Project description:Macroalgae contribute substantially to primary production in coastal ecosystems. Their biomass, mainly consisting of polysaccharides, is cycled into the environment by marine heterotrophic bacteria (MHB), using largely uncharacterized mechanisms. In Zobellia galactanivorans, we discovered and characterized the complete catabolic pathway for carrageenans, major cell wall polysaccharides of red macroalgae, providing a model system for carrageenan utilization by MHB. We further demonstrate that carrageenan catabolism relies on a multifaceted carrageenan-induced regulon, including a non-canonical polysaccharide utilization locus (PUL) and several distal genes. The genetic structure of the carrageenan utilization system is well conserved in marine Bacteroidetes, but modified in other MHB phyla. The core system is completed by additional functions which can be assumed by non-orthologous genes in different species. This complex genetic structure is due to multiple evolutionary events including gene duplications and horizontal gene transfers. These results allow for an extension on the definition of bacterial PUL-mediated polysaccharide digestion.