Sources of variation in community composition of the hindgut microbiota in two tropical Kyphosus species

Abstract Gut microbiota play a fundamental role in the nutrition of many vertebrate herbivores through foregut and hindgut fermentation plant carbohydrates. Some species marine herbivorous fishes contain moderate to high levels short-chain fatty acids hindgut, indicating importance fermentation. Herbivorous fish are diverse can vary with geographic location, but data on scale variation involving few km separation limited. Here, we used 16S rRNA gene describe community composition gut Kyphosus vaigiensis K. cinerascens collected vicinity Lizard Island, northern Great Barrier Reef, Australia, 2011 2017. Microbiota structure differed between posterior sections, host species, sampling years two mid-shelf outer reef locations approximately 20 apart. Hindgut bacterial varied remarkably locations, among individual reef. In both most abundant phyla were Pseudomonadota, Bacillota Bacteroidota, followed by Spirochaetota, Thermodesulfobacteriota Verrucomicrobiota. There no clear differences terms relative abundance genera samples. contrast, dominant samples , being Endozoicomonas- like (Pseudomonadota) Brevinema (Spirochaetota), respectively. Endozoicomonas emerging as important symbionts hosts worldwide thought be coral sulphur cycle. Differences not associated condition, suggesting that different microbial taxa perform equivalent functional roles.