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 <em>Euryarchaeota and Crenarchaeota</em> were more prevalent in rock and soil samples whereas, plant samples showed higher prevalence of bacterial phyla. Thermoacidophilic archaeons including <em>Picrophilus</em>, <em>Ferroplasma</em>, and <em>Thermogymnomonas</em> were dominant in rocks and soil samples of 1 m and 5 m distances. The rhizoplane samples were abundant with acidophilic mesophiles including <em>Ferrimicrobium</em> and <em>Granulicella</em>, whereas the rhizosphere samples were abundant with the rhizosphere-associated microbes including <em>Pseudomonas</em>, <em>Pedobacter, Rhizobium</em>, and <em>Novosphingobium. </em> 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.