宏基因组学分析揭示深古菌Bathyarchaeota B242的代谢特征

Metagenomic analysis revealing metabolic characteristics of Bathrarchaeota B242

摘要:

【背景】海洋沉积物中蕴含着丰富的微生物资源，估算约2.9×1029个细胞，与海水中的微生物总量相当。但是由于缺少可培养物，大部分的微生物缺乏生理特征、代谢方式以及生态功能的相关研究。深古菌(Bathyarchaeota)是一类典型的未培养微生物，在全球海洋沉积物中普遍存在，并且具有很高的丰度。【目的】对深古菌代谢潜能及其在海洋沉积物中发挥的生态功能进行更加深入的研究。【方法】应用宏基因组学的技术手段，对采集自瓜伊马斯盆地的深海热液沉积物样本进行了分析，获得了一个接近完整的深古菌基因组Bathyarchaeota B242。【结果】对Bathyarchaeota B242基因组的分析发现，其具有以降解蛋白质和多种碳水化合物为主的异养代谢途径，同时还具有通过还原型乙酰辅酶A途径实现的自养途径。【结论】同时具有自养和异养代谢途径对Bathyarchaeota B242适应低物质能量供给环境下的生存起到重要作用。

Abstract:

[Background] Approximately 2.9×1029 cells reside in marine sediments, roughly equal to the estimates of cell abundance in seawater. Due to the lack of cultivated representative species of these microbes in laboratories, their physiology and metabolic functions remain largely unknown. The members of Bathyarchaeota are typical sedimentary microorganisms and widely distributed in global marine sediments. [Objective] For further understanding of their metabolic potential and ecological roles that remain largely elusive. [Methods] Samples from Guaymas Basin hydrothermal sediment were analyzed by metagenomic technology, and a near-complete genome belonging to Bathyarchaeota B242 was obtained. [Results] Through comprehensive genomic analysis, Bathyarchaeota B242 was found having heterotrophic mode of life style mainly through protein fermentation, carbohydrate utilization as well as possess autotrophic acetogenic pathway that helps survive under energy deficient environments. [Conclusion] The heterotrophic and autotrophic metabolic mode together contributed to the adaptation in energy deficient marine sediments for Bathyarchaeota.