The marine natural microbiome mediates physiological outcomes in host nematodes

Abstract

AbstractNematodes are the most abundant metazoans in marine sediments, many of which are bacterivores, however how habitat bacteria effects physiological outcomes in marine nematodes remains largely unknown. Here, we used aLitoditis marinainbred line to assess how native bacteria modulates host nematode physiology. We characterized seasonal dynamic bacterial compositions inL. marinahabitats, and examined the impacts of 448 habitat bacteria isolates onL. marinadevelopment, then focused on HQbiome with 73 native bacteria, of which we generated 72 whole genomes sequences. Unexpectedly, we found that the effects of marine native bacteria on the development ofL. marinaand its terrestrial relativeCaenorhabditis eleganswere significantly positively correlated. Next, we reconstructed bacterial metabolic networks and identified several bacterial metabolic pathways positively correlated withL. marinadevelopment (e.g., ubiquinol and hemebbiosynthesis), while pyridoxal 5’-phosphate biosynthesis pathway was negatively associated. Through single metabolite supplementation, we verified CoQ10, hemeb, Acetyl-CoA, and acetaldehyde promotedL. marinadevelopment, while vitamin B6 attenuated growth. Notably, we found that only four development correlated metabolic pathways were shared betweenL. marinaandC. elegans. Furthermore, we identified two bacterial metabolic pathways correlated withL. marinalifespan, while a distinct one inC. elegans. Strikingly, we found that glycerol supplementation significantly extendedL. marinabut notC. eleganslongevity. Moreover, we comparatively demonstrated the distinct gut microbiota characteristics and their effects onL. marinaandC. elegansphysiology. Our integrative approach will provide a microbe–nematodes framework for microbiome mediated effects on host animal fitness.