SAR202 in Chloroflexi phylum plays an important role in degradation of organic compounds in the oligotrophic deep ocean. Due to lack of high-quality genomes from across all depths of the water column, the metabolic capacities of the SAR202 subclusters in the marine environment were still largely unknown. In this study, we discovered the dynamics of the SAR202 subclusters in vertical layers of global ocean. A total of 11 metagenome-assembled genomes (MAGs) in various sizes were obtained from two SAR202 subclusters in the Mariana Trench. Genomic comparison revealed that vitamin B₁₂ (VB12) synthesis was restricted to the subcluster III. In addition, the presence of a large number of genes encoding the oxidase and degradation pathways indicates that the SAR202 bacteria are probably capable of metabolizing chitin, aromatic compounds, dimethyl sulfoxide and osmolytes in the environment. With the predicted genes responsible for sulfite oxidation and export, SAR202 could potentially play important roles in biogeochemical cycles. This study highlights the genetic plasticity and ecological role of SAR202 in deep-sea zones.

绿叶弯曲菌中的SAR202在贫营养型深海中的有机化合物降解中起重要作用。由于缺乏来自水柱所有深度的高质量基因组，SAR202亚群在海洋环境中的代谢能力仍是未知之数。在这项研究中，我们发现了SAR202亚群在全球海洋垂直层中的动力学。从马里亚纳海沟的两个SAR202亚类中获得了总计11个不同大小的元基因组组装基因组（MAG）。基因组比较显示维生素B ₁₂（VB12）合成仅限于子类III。此外，大量编码氧化酶和降解途径的基因的存在表明，SAR202细菌可能能够在环境中代谢几丁质，芳香族化合物，二甲基亚砜和渗透压剂。有了预测的负责亚硫酸盐氧化和输出的基因，SAR202可能在生物地球化学循环中发挥重要作用。这项研究突出了SAR202在深海地区的遗传可塑性和生态作用。