Culturable bacterial diversity in soils of Inexpressible Island, Antarctica

Abstract:

[Background] The environment in Antarctic is harsh and few plants coverage. The ice-free area only accounts for 0.4% of the total area, but accompanied with abundant microbial communities in the soil. Polar microbial resources need to be further explored. [Objective] This study was to obtain information on the diversity of culturable bacteria in soils from Inexpressible Island, Antarctica. [Methods] We isolated bacteria in the five soil samples from Inexpressible Island, Antarctica. Three different cultivation methods were applied, including directly spreading, microaerobic enrichment and aerobic enrichment method. [Results] A total of 144 culturable bacteria were obtained. These culturable bacteria belonged to 30 genera, and divided into 5 phyla, which consisted of Proteobacteria (38.9%), Actinobacteria (34.0%), Firmicutes (22.2%), Deinococcus-Thermus (3.5%) and Bacteroidetes (1.4%). Diversity of culturable bacteria in different soil samples was different. Bacillus dominated in soil from Penguin activity area. Pseudomonas and Streptomyces dominated in soil from mosses and lichens coverage area. Psychrobacter dominated in lakeside soil, with Flavobacterium and Chryseobacterium were isolated only in this sample. Actinobacteria were dominant in dry soils, such as Pseudarthrobacter, Rhodococcus and Microbacterium were isolated only from dry soil samples. It was suggested that 2 isolates were found to be potential novel species for their low 16S rRNA gene sequence similarity. [Conclusion] There are exploitable bacterial resources in the soil of Inexpressible Island, Antarctica. This paper also provides some basic data for the study of bacterial diversity in this area.