Genomic analysis of Vibrio sp. D3 reveals its role in marine sulfur cycling.

Abstract

Dimethylsulfoniopropionate (DMSP) is an important organosulfur compound, with key roles in global carbon and sulfur cycling, stress tolerance, chemotaxis, and, potentially, climate regulation. The strain Vibrio sp. D3 was isolated from the surface seawater samples in Qingdao coastal area, which could grow on DMSP as sole carbon source. Here, we report the complete genome sequence of strain D3 and analyzed its genomic characteristics related to the sulfur metabolism, especially DMSP. The genome of strain D3 contains two circular chromosomes of total 5,104,020 bp with a mean GC content of 44.87 %. DMSP transporter gene bccT and acryloy-CoA reductase gene acuI, which is essential in DMSP cleavage, are identified in the genome of Vibrio sp. D3. Potential DMSP demethylase gene dmdA (26.07 %, amino acid sequence identity) and DMSP lyase gene dddX (26.32 %, amino acid sequence identity) are predicted in the genome of strain D3, whose functions need further experimental verification. Vibrio sp. D3 also contains _L-Met gamma-lyase (MegL) to generate MeSH from _L-Met and complete assimilatory sulfate reduction pathway. Together, the genome of strain D3 reveals the possible DMSP catabolic pathways and supports its role in sulfur cycling.