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

Abstract:

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.