Molecular profiling of microbial community structure and their potential functions in the Siaoyoukeng geothermal field across rock-soil -plant continuum using high-throughput sequencing

Growing evidence suggests that hydrochemical properties of hot springs influence the inhabiting microbial community. However, their influence on microbial communities residing in rock-soil -plant continuum of nearby harsh hot springs is poorly understood. This study deciphered the microbial community of rock-soil -plant continuum in Siaoyoukeng geothermal area, Taiwan. The results revealed that bacterial phylum Proteobacteria was predominant in all sample types irrespective of sampling distance except in 10 m rock sample. Archaeal phyla such as Euryarchaeota and Crenarchaeota were more prevalent in rock and soil samples whereas, plant samples showed higher prevalence of bacterial phyla. Thermoacidophilic archaeons including Picrophilus, Ferroplasma, and Thermogymnomonas were dominant in rocks and soil samples of 1 m and 5 m distances. The rhizoplane samples were abundant with acidophilic mesophiles including Ferrimicrobium and Granulicella, whereas the rhizosphere samples were abundant with the rhizosphere-associated microbes including Pseudomonas, Pedobacter, Rhizobium, and Novosphingobium. Sulfur oxidative pathways were highly expressed specifically in rock and soil samples of 1m and 5m distances, whereas in plant samples dark iron oxidation and nitrate/nitrogen respiration were relatively abundant. Collectively, these results provide comprehensive information on microbial communities across rock-soil-plant continuum in geothermal field characterized by harsh geochemical features.