Hindguts of Kyphosus sydneyanus harbor phylogenetically and genomically distinct Alistipes capable of degrading algal polysaccharides and diazotrophy

Abstract

Despite numerous reports of the Alistipes genus in humans and ruminants, its diversity and function remain understudied, and there is no clear consensus on whether it positively or negatively impacts host health. Given the symbiotic role of gut communities in the Kyphosus sydneyanus hindgut, where Alistipes are prevalent, and the diversity of carbohydrate-active enzymes (CAZymes) encoded that likely contribute to the breakdown of important substrates in the host diet, it is likely that this genus provides essential services to the fish host. Therefore, considering its metabolism in various contexts and hosts is crucial for understanding the ecology of the genus. Our study highlights the distinct genetic traits of Alistipes based on host association, and the potential of fish-associated Alistipes to transform macroalgae biomass into nutraceuticals (alginate oligosaccharides, β-glucans, sulfated galactans, and sulfated fucans).