Microbial sulfur cycle in two hydrothermal chimneys on the Southwest Indian Ridge.
Microbial sulfur cycle in two hydrothermal chimneys on the Southwest Indian Ridge.
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DOI：
10.1128/mbio.00980-13
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发表时间：
2014-01-28
期刊：
影响因子：
6.4
通讯作者：
Qian PY
中科院分区：
文献类型：
--
作者：
Cao H;Wang Y;Lee OO;Zeng X;Shao Z;Qian PY
硫是维持热液喷口微生物群落的重要元素。硫氧化由于其在热液领域化学合成途径中的重要性而被广泛研究;然而，对硫酸盐还原知之甚少。在这里，位于超低速扩张的西南印度洋脊（SWIR）的热液烟囱的宏基因组进行了焦磷酸测序，以阐明相关的微生物硫循环。已知基因的分类学总结揭示了一些参与微生物硫循环的优势细菌，特别是硫酸盐还原Deltaproteobacteria。所研究的宏基因组含有高度丰富的与硫氧化和还原相关的基因。几个碳代谢途径，特别是Calvin-Benson-Bassham途径和还原性三羧酸循环CO2固定，确定在硫氧化自养细菌。与此相反，高丰度的短链烷烃氧化相关的基因与硫酸盐还原菌分组，表明短链烷烃在硫循环中的重要作用。此外，硫氧化细菌与富集的基因参与反硝化途径，而硫酸盐还原菌显示富集的基因负责氢的利用。总之，这项研究提供了关于主要微生物代谢活动的见解，这些活动是由硫循环驱动的低温热液烟囱存在于超低的米氏脊上。对位于超低速扩张洋脊的烟囱状硫化物的研究有限。对超低速扩张的西南印度洋脊热液烟囱的宏基因组分析表明存在微生物硫循环。硫循环应该集中在一个微生物群落，显示富集硫代谢相关基因。本研究阐明了微生物硫循环在维持整个微生物群落在低温热液烟囱中的一个重要作用，在一个超低速扩展的米氏脊，它具有不同于其他类型的热液领域的特点。
Sulfur is an important element in sustaining microbial communities present in hydrothermal vents. Sulfur oxidation has been extensively studied due to its importance in chemosynthetic pathways in hydrothermal fields; however, less is known about sulfate reduction. Here, the metagenomes of hydrothermal chimneys located on the ultraslow-spreading Southwest Indian Ridge (SWIR) were pyrosequenced to elucidate the associated microbial sulfur cycle. A taxonomic summary of known genes revealed a few dominant bacteria that participated in the microbial sulfur cycle, particularly sulfate-reducing Deltaproteobacteria. The metagenomes studied contained highly abundant genes related to sulfur oxidation and reduction. Several carbon metabolic pathways, in particular the Calvin-Benson-Bassham pathway and the reductive tricarboxylic acid cycles for CO2 fixation, were identified in sulfur-oxidizing autotrophic bacteria. In contrast, highly abundant genes related to the oxidation of short-chain alkanes were grouped with sulfate-reducing bacteria, suggesting an important role for short-chain alkanes in the sulfur cycle. Furthermore, sulfur-oxidizing bacteria were associated with enrichment for genes involved in the denitrification pathway, while sulfate-reducing bacteria displayed enrichment for genes responsible for hydrogen utilization. In conclusion, this study provides insights regarding major microbial metabolic activities that are driven by the sulfur cycle in low-temperature hydrothermal chimneys present on an ultraslow midocean ridge. There have been limited studies on chimney sulfides located at ultraslow-spreading ridges. The analysis of metagenomes of hydrothermal chimneys on the ultraslow-spreading Southwest Indian Ridge suggests the presence of a microbial sulfur cycle. The sulfur cycle should be centralized within a microbial community that displays enrichment for sulfur metabolism-related genes. The present study elucidated a significant role of the microbial sulfur cycle in sustaining an entire microbial community in low-temperature hydrothermal chimneys on an ultraslow spreading midocean ridge, which has characteristics distinct from those of other types of hydrothermal fields.