title: Purine catabolic pathway revealed by transcriptomics in the model marine bacterium Ruegeria pomeroyi DSS-3.
abstract: Purines are nitrogen-rich compounds that are widely distributed in the marine environment and are an important component of the dissolved organic nitrogen (DON) pool. Even though purines have been shown to be degraded by bacterioplankton, the identities of marine bacteria capable of purine degradation and their underlying catabolic mechanisms are currently unknown. This study shows that Ruegeria pomeroyi, a model marine bacterium and Marine Roseobacter Clade (MRC) representative, utilizes xanthine as a source of carbon and nitrogen. The R. pomeroyi genome contains putative genes that encode xanthine dehydrogenase (XDH), which is expressed during growth with xanthine. RNAseq-based analysis of the R. pomeroyi transcriptome revealed that the transcription of an XDH-initiated catabolic pathway is up-regulated during growth with xanthine, with transcription greatest when xanthine was the only available carbon source. The RNAseq-deduced pathway indicates that glyoxylate and ammonia are the key intermediates from xanthine degradation. Utilising a laboratory model, this study has identified the potential genes and catabolic pathway active during xanthine degradation. The ability of R. pomeroyi to utilize xanthine provides novel insights into the capabilities of the MRC that may contribute to their success in marine ecosystems and the potential biogeochemical importance of the group in processing DON.
authors.affiliation: Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK Marine Biology and Ecology Research Centre, Marine Institute, Plymouth University, Drake Circus, Plymouth PL4 8AA, UK micnli@mba.ac.uk.
authors.forename: Michael
authors.initials: M
authors.lastname: Cunliffe
mesh_terms: D059001:Aquatic Organisms / Q000378:metabolism; D001483:Base Sequence; D002244:Carbon / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D041902:Rhodobacteraceae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D041904:Roseobacter / Q000378:metabolism; D017423:Sequence Analysis, RNA; D014871:Water Microbiology; D019820:Xanthine / Q000378:metabolism*; D014968:Xanthine Dehydrogenase / Q000235:genetics*
chemical_list: D019820:Xanthine; D002244:Carbon; D014968:Xanthine Dehydrogenase; D009584:Nitrogen
keywords: bacterioplankton; marine; purines; transcriptomics