Abstract：
Dimethylsulfoniopropionate (DMSP) is a ubiquitous organosulfur molecule in marine environments with important roles in stress tolerance, global carbon and sulfur cycling, and chemotaxis. It is the main precursor of the climate active gas dimethyl sulfide (DMS), which is the greatest natural source of bio‑sulfur transferred from ocean to atmosphere. Alteromonas sp. M12, a Gram-negative and aerobic bacterium, was isolated from the seawater samples collected from the Mariana Trench at the depth of 2500 m. Here, we report the complete genome sequence of strain M12 and its genomic characteristics to import and utilize DMSP. The genome of strain M12 contains one circular chromosome (5,012,782 bp) with the GC content of 40.88%. Alteromonas sp. M12 can grow with DMSP as a sole carbon source, and produced DMS with DMSP as a precursor. Genomic analysis showed that strain M12 contained a set of genes involved in the downstream steps of DMSP cleavage, but no known genes encoding DMSP transporters or DMSP lyases. The results indicated that this strain contained novel DMSP transport and cleavage genes in its genome which warrants further investigation. The import of DMSP into cells may be a strategy of strain M12 to adapt the hydrostatic pressure environment in the Mariana Trench, as DMSP can be used as a hydrostatic pressure protectant. This study sheds light on the catabolism of DMSP by deep-sea bacteria.
摘要：
二甲基磺丙酸酯（DMSP）是海洋环境中普遍存在的有机硫分子，在胁迫耐受性中具有重要作用。全球碳和硫循环，和趋化性。它是气候活性气体二甲基硫醚（DMS）的主要前体，这是从海洋转移到大气的生物硫的最大天然来源。Alteromonassp.M12，一种革兰氏阴性和需氧细菌，是从马里亚纳海沟2500米深处收集的海水样本中分离出来的。我们报告了菌株M12的完整基因组序列及其基因组特征，以导入和利用DMSP。菌株M12的基因组包含一条环状染色体（5,012,782bp），GC含量为40.88%。Alteromonassp.M12可以在DMSP作为唯一碳源的情况下生长，并以DMSP为前体生产DMS。基因组分析表明，菌株M12包含一组参与DMSP裂解下游步骤的基因，但没有已知的基因编码DMSP转运蛋白或DMSP裂解酶。结果表明，该菌株在其基因组中包含新的DMSP转运和切割基因，值得进一步研究。将DMSP导入细胞可能是菌株M12适应马里亚纳海沟静水压力环境的策略，因为DMSP可以用作静水压力保护剂。本研究揭示了深海细菌对DMSP的分解代谢。
