Genetic Potential for Trimethylamine Production in a Marine Oxygen Deficient Zone

Abstract:

Trimethylamine (TMA) is a N-containing metabolite that can be used by marine microorganisms as a carbon, nitrogen, and energy source. TMA is a substrate for methane formation, and TMA and its degradation byproducts are aerosolizable and can flux into the atmosphere and affect the climate. While microbial TMA production and degradation pathways have been studied in marine sediments and oxygenated oceans, they have not been well explored in oxygen deficient zones (ODZs), which play a disproportionate role in global nitrogen cycling. We used a combination of BLAST searches and KEGG assignments to identify members of the dimethyl sulfoxide reductase superfamily that are able to convert the osmolyte trimethylamine N-oxide (TMAO) to TMA in a suite of metagenomes collected from the eastern tropical North Pacific ODZ. We generated a maximum-likelihood phylogenetic tree and identified torA-like and torZ-like sequences throughout the ODZ suggesting the genomic potential for TMA production within an oxygen deficient zone.