Trimethylamine N -oxide metabolism by abundant marine heterotrophic bacteria

Abstract

Significance Trimethylamine N -oxide (TMAO) is a nitrogen-containing osmolyte found in a wide variety of marine biota and has been detected at nanomolar concentrations in surface seawaters. This study provides the first genetic and biochemical evidence for uptake and catabolism of TMAO by marine heterotrophic bacteria that are abundant in the oceans. The genes conferring the ability of bacteria to catabolize TMAO we identified in this study are highly expressed in the marine environment and can be used as functional biomarkers to better understand oceanic microbial-mediated carbon and nitrogen cycles. Our data suggest that TMAO represents a significant, yet overlooked, nutrient for marine bacteria in the surface oceans.