弯曲杆菌内的化学自养生物,尤其是硫磺属和硫磺属,在南中国海福尔摩沙冷渗漏的海水-沉积物界面中含量丰富。然而,弯曲杆菌的原位活性和功能尚不清楚。在这项研究中,用多种手段研究了弯曲菌在福尔摩沙冷渗漏中的地球化学作用。首次从深海冷渗漏中分离出硫磺属和硫磺属的两名成员。这些分离物是新的化学自养物种,可以使用分子氢作为能源,使用CO2作为唯一的碳源。比较基因组学确定了硫磺属和硫磺属中重要的氢氧化簇。代谢组学分析检测到RS中氢氧化基因的高表达,这表明H2可能是寒冷渗漏中的能源。基因组分析表明,硫磺属和硫磺属分离株具有截短的硫氧化系统,和代谢组学分析显示,具有此基因型的硫磺属和硫磺属在RS表面具有活性,可能有助于硫代硫酸盐的产生。此外,地球化学和原位分析显示,由于微生物的消耗,沉积物-水界面中的硝酸盐浓度急剧下降。始终如一,硫单胞菌和硫磺属的反硝化基因高表达,表明这些细菌对氮循环的重要贡献。总的来说,这项研究表明,在深海冷渗漏中,弯曲杆菌在氮和硫的循环中起着重要作用。弯曲杆菌内的重要性化学自养生物,特别是硫磺属和硫磺属,在深海冷渗漏和热液喷口中无处不在。然而,到目前为止,没有从寒冷的渗漏中分离出硫磺属或硫磺属,这些细菌在寒冷渗漏中的生态作用仍有待研究。在这项研究中,我们从福尔摩沙冷渗漏中获得了两个硫磺属和硫磺属的分离株,南中国海。比较基因组学,metatranscriptomics,地球化学分析,原位实验研究共同表明,弯曲菌在冷渗漏中的氮和硫循环中起着重要作用,是硫代硫酸盐积累和沉积物-水界面硝酸盐含量急剧降低的原因。这项研究的发现促进了我们对深海弯曲杆菌的原位功能和生态作用的理解。
Chemoautotrophs within Campylobacterota, especially Sulfurovum and Sulfurimonas, are abundant in the seawater-sediment interface of the Formosa cold seep in the South China Sea. However, the in situ activity and function of Campylobacterota are unknown. In this study, the geochemical role of Campylobacterota in the Formosa cold seep was investigated with multiple means. Two members of Sulfurovum and Sulfurimonas were isolated for the first time from deep-sea cold seep. These isolates are new chemoautotrophic species that can use molecular
hydrogen as an energy source and CO2 as a sole carbon source. Comparative genomics identified an important
hydrogen-oxidizing cluster in Sulfurovum and Sulfurimonas. Metatranscriptomic analysis detected high expression of
hydrogen-oxidizing gene in the RS, suggesting that H2 was likely an energy source in the cold seep. Genomic analysis indicated that the Sulfurovum and Sulfurimonas isolates possess a truncated sulfur-oxidizing system, and metatranscriptomic analysis revealed that Sulfurovum and Sulfurimonas with this genotype were active in the surface of RS and likely contributed to thiosulfate production. Furthermore, geochemical and in situ analyses revealed sharply decreased nitrate concentration in the sediment-water interface due to microbial consumption. Consistently, the denitrification genes of Sulfurimonas and Sulfurovum were highly expressed, suggesting an important contribution of these bacteria to nitrogen cycling. Overall, this study demonstrated that Campylobacterota played a significant role in the cycling of nitrogen and sulfur in a deep-sea cold seep. IMPORTANCE Chemoautotrophs within Campylobacterota, in particular Sulfurovum and Sulfurimonas, are ubiquitous in deep-sea cold seeps and hydrothermal vents. However, to date, no Sulfurovum or Sulfurimonas has been isolated from cold seeps, and the ecological roles of these bacteria in cold seeps remain to be investigated. In this study, we obtained two isolates of Sulfurovum and Sulfurimonas from Formosa cold seep, South China Sea. Comparative genomics, metatranscriptomics, geochemical analysis, and in situ experimental study indicated collectively that Campylobacterota played a significant part in nitrogen and sulfur cycling in cold seep and was the cause of thiosulfate accumulation and sharp reduction of nitrate level in the sediment-water interface. The findings of this study promoted our understanding of the in situ function and ecological role of deep-sea Campylobacterota.