Analysis of Microbial Diversity in South Shetland Islands and Antarctic Peninsula Soils Based on Illumina High-Throughput Sequencing and Cultivation-Dependent Techniques.

To assess the diversity of bacterial taxa in Antarctic soils and obtain novel microbial resources, 15 samples from 3 sampling sites (DIS5, GWS7, FPS10) of South Shetland Islands and 2 sampling sites (APS18, CIS17) of Antarctic Peninsula were collected. High-throughput sequencing (HTS) of 16S rRNA genes within these samples was conducted on an Illumina Miseq platform. A total of 140,303 16S rRNA gene reads comprising 802 operational taxonomic units (OTUs) were obtained. After taxonomic classification, 25 phyla, 196 genera, and a high proportion of unidentified taxa were detected, among which seven phyla and 99 genera were firstly detected in Antarctica. The bacterial communities were dominated by Actinomycetota (40.40%), Pseudomonadota (17.14%), Bacteroidota (10.55%) and Chloroflexota (10.26%). Based on the HTS analyses, cultivation-dependent techniques were optimized to identify the cultivable members. A total of 30 different genera including 91 strains were obtained, the majority of which has previously been reported from Antarctica. However, for the genera Microterricola , Dyadobacter , Filibacter , Duganella , Ensifer , Antarcticirhabdus and Microvirga , this is the first report in Antarctica. In addition, seven strains represented novel taxa, two of which were psychropoilic and could be valuable resources for further research of cold-adaptability and their ecological significance in Antarctica.