Department of Pathogenic Biology, College of Basic Medicine, Jining Medical University, 272067, Jining, Shandong, P. R. China.
School of Basic Medical Sciences, Shandong Second Medical University, 261042, Weifang, Shandong, P. R. China.
BMC Genomics. 2024 Apr 22;25(1):389. doi: 10.1186/s12864-024-10269-3.
The genus Sulfitobacter, a member of the family Roseobacteraceae, is widely distributed in the ocean and is believed to play crucial roles in the global sulfur cycle. However, gene clusters associated with sulfur oxidation in genomes of the type strains of this genus have been poorly studied. Furthermore, taxonomic errors have been identified in this genus, potentially leading to significant confusion in ecological and evolutionary interpretations in subsequent studies of the genus Sulfitobacter. This study aims to investigate the taxonomic status of this genus and explore the metabolism associated with sulfur oxidation.
This study suggests that Sulfitobacter algicola does not belong to Sulfitobacter and should be reclassified into a novel genus, for which we propose the name Parasulfitobacter gen. nov., with Parasulfitobacter algicola comb. nov. as the type species. Additionally, enzymes involved in the sulfur oxidation process, such as the sulfur oxidization (Sox) system, the disulfide reductase protein family, and the sulfite dehydrogenase (SoeABC), were identified in almost all Sulfitobacter species. This finding implies that the majority of Sulfitobacter species can oxidize reduced sulfur compounds. Differences in the modular organization of sox gene clusters among Sulfitobacter species were identified, along with the presence of five genes with unknown function located in some of the sox gene clusters. Lastly, this study revealed the presence of the demethylation pathway and the cleavage pathway used by many Sulfitobacter species to degrade dimethylsulfoniopropionate (DMSP). These pathways enable these bacteria to utilize DMSP as important source of sulfur and carbon or as a defence strategy.
Our findings contribute to interpreting the mechanism by which Sulfitobacter species participate in the global sulfur cycle. The taxonomic rearrangement of S. algicola into the novel genus Parasulfitobacter will prevent confusion in ecological and evolutionary interpretations in future studies of the genus Sulfitobacter.
硫杆菌属（Sulfitobacter）是红杆菌科（Roseobacteraceae）的一个成员，广泛分布于海洋中，被认为在全球硫循环中起着至关重要的作用。然而，该属的模式菌株基因组中与硫氧化相关的基因簇尚未得到充分研究。此外，该属中已发现分类错误，这可能导致在后续的硫杆菌属研究中对其生态和进化解释产生重大混淆。本研究旨在调查该属的分类地位，并探讨与硫氧化相关的代谢。
本研究表明，硫杆菌属的 Algicola 种不属于硫杆菌属，应重新归类为一个新属，我们建议将其命名为 Parasulfitobacter 属，新种为 Parasulfitobacter algicola comb. nov.。此外，几乎所有的硫杆菌属物种都鉴定出了参与硫氧化过程的酶，如硫氧化（Sox）系统、二硫键还原酶家族和亚硫酸脱氢酶（SoeABC）。这一发现表明，大多数硫杆菌属物种可以氧化还原态的硫化合物。还发现了硫杆菌属物种中 sox 基因簇的模块化组织存在差异，以及一些 sox 基因簇中存在 5 个具有未知功能的基因。最后，本研究揭示了许多硫杆菌属物种降解二甲基巯基丙酸（DMSP）所使用的去甲基化途径和裂解途径。这些途径使这些细菌能够将 DMSP 作为硫和碳的重要来源或作为防御策略加以利用。
我们的研究结果有助于解释硫杆菌属参与全球硫循环的机制。将 Algicola 种从硫杆菌属重新分类到新的 Parasulfitobacter 属中，将防止在未来的硫杆菌属研究中对生态和进化解释产生混淆。
