AUTHOR=Sun Fulin , Wang Youshao , Jiang Zhaoyu , Sun Cuici , Wang Yutu , Wu Meilin 

TITLE=Abundance and Diversity of Dimethylsulfoniopropionate Degradation Genes of Roseobacter Group in the Northern South China Sea

JOURNAL=Frontiers in Marine Science

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.895613

DOI=10.3389/fmars.2022.895613

ISSN=2296-7745

ABSTRACT=<p>Bacterial degradation of dimethylsulfoniopropionate (DMSP) plays a significant role in ecosystem productivity and global climate. In this study, the abundance and diversity of <italic>Roseobacter</italic> group DMSP degradation genes were explored in spatial scale of the South China Sea (SCS). Quantitative PCR showed that a higher abundance of <italic>dmdA</italic> (DMSP demethylase) and <italic>dddP</italic> (DMSP lyase) genes was detected above 75 m than deep water, especially in surface water. A high ratio of <italic>dmdA</italic>/<italic>dddP</italic> existed in all sites and increased with water depth, indicating that demethylation was the main degradation pathway in the <italic>Roseobacter</italic> group. High-throughput sequencing analysis showed that distribution of <italic>dmdA</italic> gene had a significant layering structure in the northern SCS, and high taxonomic diversity of <italic>dmdA</italic> gene was observed in near-surface waters (25 and 50 m). <italic>DmdA</italic> gene in the <italic>Roseobacter</italic> group, such as <italic>Leisingera</italic>, <italic>Nioella</italic>, <italic>Roseobacter</italic>, <italic>Roseovarius</italic>, <italic>Donghicola</italic>, <italic>Phaeobacter</italic>, and <italic>Tateyamaria</italic>, had remarkable specificity due to the effect of different sites and water depths. Different ecological strategies of DMSP degradation may be used by members of the bacterial community harboring demethylation genes. In addition, many <italic>dmdA</italic> sequences were affiliated with unidentified bacteria, indicating that the SCS reserved high diversity of DMSP-degrading bacteria. Canonical correspondence analysis (CCA) suggested that temperature and depth were the most important factors to determine the taxonomic distribution of DMSP degradation genes in the <italic>Roseobacter</italic> group, as well as their abundance. This study highlighted the understanding of the role of <italic>Roseobacter</italic> group in DMSP degradation in the tropical ocean.</p>