Methanethiol and dimethylsulfide cycling in Stiffkey salt marsh. sediment metagenome

Dimethylsulfide (DMS) is an environmentally important trace gas with roles in sulphur cycling, signalling to higher organisms and in atmospheric chemistry. DMS is believed to be predominantly produced in marine environments via microbial degradation of the osmolyte dimethylsulfoniopro- pionate (DMSP). However, significant amounts of DMS are also generated from terrestrial environments and sediments, for example, peat bogs can emit ~ 6 μmol DMS m − 2 per day, likely via the methylation of methanethiol (MeSH). A methyltransferase enzyme termed ‘MddA’, which catalyses the methylation of MeSH generating DMS in a wide range of bacteria and some cyanobacteria, may mediate this process, as the mddA gene is abundant in terrestrial and sediment metagenomes. This is the first study investigating the functionality of MeSH-dependent DMS production (Mdd) in a wide range of aerobic environments.