Methanethiol and Dimethylsulfide Cycling in Stiffkey Saltmarsh

Carrion Fonseca, Ornella, Pratscher, Jenny, Richa, Kumari, Rostant, Wayne, Farhan Ul Haque, Muhammad, Murrell, John and Todd, Jonathan (2019) Methanethiol and Dimethylsulfide Cycling in Stiffkey Saltmarsh. Frontiers in Microbiology, 10. ISSN 1664-302X

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    Abstract

    Methanethiol (MeSH) and dimethylsulfide (DMS) are volatile organic sulfur compounds (VOSCs) with important roles in sulfur cycling, signaling and atmospheric chemistry. DMS can be produced from MeSH through a reaction mediated by the methyltransferase MddA. The mddA gene is present in terrestrial and marine metagenomes, being most abundant in soil environments. The substrate for MddA, MeSH, can also be oxidized by bacteria with the MeSH oxidase (MTO) enzyme, encoded by the mtoX gene, found in marine, freshwater and soil metagenomes. Methanethiol-dependent DMS production (Mdd) pathways have been shown to function in soil and marine sediments, but have not been characterized in detail in the latter environments. In addition, few molecular studies have been conducted on MeSH consumption in the environment. Here, we performed process measurements to confirm that Mdd-dependent and Mdd-independent MeSH consumption pathways are active in tested surface saltmarsh sediment when MeSH is available. We noted that appreciable natural Mdd-independent MeSH and DMS consumption processes masked Mdd activity. 16S rRNA gene amplicon sequencing and metagenomics data showed that Methylophaga, a bacterial genus known to catabolise DMS and MeSH, was enriched by the presence of MeSH. Moreover, some MeSH and/or DMS-degrading bacteria isolated from this marine environment lacked known DMS and/or MeSH cycling genes and can be used as model organisms to potentially identify novel genes in these pathways. Thus, we are likely vastly underestimating the abundance of MeSH and DMS degraders in these marine sediment environments. The future discovery and characterization of novel enzymes involved in MeSH and/or DMS cycling is essential to better assess the role and contribution of microbes to global organosulfur cycling.

    Item Type: Article
    Uncontrolled Keywords: methanethiol (mesh),dimethylsulfide (dms),saltmarsh,sulfur cycling
    Faculty \ School: Faculty of Science > School of Environmental Sciences
    Faculty of Science > School of Biological Sciences
    Depositing User: LivePure Connector
    Date Deposited: 15 May 2019 16:30
    Last Modified: 04 Jul 2019 01:11
    URI: https://ueaeprints.uea.ac.uk/id/eprint/71004
    DOI: 10.3389/fmicb.2019.01040

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