海底深部生物圈菌株泛酸枝芽孢杆菌19R1-5的来源和代谢特征分析

河流输送大量的陆源有机物、无机物和微生物到海洋,沉积到近海海盆。随着陆源和海源沉积物在盆地的逐渐堆积,这些陆源微生物被埋藏,进而逐渐演变为沉积物中固有微生物群体的一部分,是研究微生物环境适应与进化的理想生态系统。本课题组从国际大洋钻探计划(IODP) 337航次的一个西太平洋煤层岩芯(1 999 mbsf, meter below the seafloor)中,成功分离到一株革兰氏阳性细菌泛酸枝芽孢杆菌19R1-5(19R)。研究发现,19R与分离自陆源土壤的泛酸枝芽孢杆菌DSM 26(26^T)相比,16S rRNA基因序列相似性为100%,DNA杂交同源性高达91.7%。我们将19R和26^T作为研究对象,从比较基因组的角度对19R的来源和代谢潜能进行研究。结果表明,分离自海底深部的19R来源于陆地;同时,19R较26^T拥有3个额外的磷酸葡萄糖转移酶系统(PTS),提示19R具有更强的糖利用能力,使之能够适应原位中特殊的营养环境,研究结果对探索海底深部生物圈微生物的来源及其在深海物质循环中的作用具有重要意义。

Origin and metabolic characteristics of deep seabed biosphere strain Virgibacilus pantothenticus 19R1-5

Rivers transport large amounts of terrestrial organic matter, inorganic matter, and microorganisms to the ocean, where they are deposited into offshore basins.With the gradual accumulation of terrigenous and marine sediments in the basin, these terrigenous microorganisms were buried and gradually evolved into a part of the inherent microbial community in the sediments. It is an ideal ecosystem for studying the adaptation and evolution of microbial environment.A Gram-positive bacterium Virgibacilus pantothenticus 19R1-5(19R) was successfully isolated from a coal seam core (1 999 mbsf, meter below the seafloor) in the Western Pacific Ocean during the International Ocean Drilling Program (IODP) Expedition 337 by our research group.The 16S rRNA sequence of 19R was 100% similar to that of Virgibacilus pantothenticus DSM 26(26^T) isolated from land-based soil, and the homology of DNA hybridization was 91.7%.We studied the origin and metabolic potential of 19R and 26^T from the perspective of comparative genomes.The results show that the 19R isolated from the deep seabed originated from the land. Compared with 26^T, 19R has three additional PTS systems, suggesting that 19R has stronger sugar utilization capacity, which enables it to adapt to the special nutritional environment in deep biosphere.The results of this study are of great significance for exploring the origin of microorganisms in the deep seabed biosphere and their role in the deep sea material circulation.