关键词: 南极, 土壤微生物, 宏基因组, 生物多样性, 高通量测序, Antarctic region, soil microbes, metagenomics, biodiversity, high-throughput sequencing

Abstract: The study of microbiomes using metagenomic high-throughput sequencing enables the analysis of uncultivated microbial populations that may play important roles in the environment. The Antarctic is an extreme environment where pole-end temperature, radiation, and desiccation limit most of life activities. Through long term adaptation and evolution, the microbial populations form special biodiversity and genetic backgrounds, develop various metabolic pathways that produce enzymes and active substances with special functions. These precious bioresources can be used as biofuels, medicine or for environmental protection and other fields widely. In order to discover the biodiversity and community structure of the microorganisms in the Antarctic soil, we collected 3 soil samples from Antarctic Fildes Peninsula as the study objectives. Initially, we obtained the diversity information through metagenomic high-throughput sequencing. MetaPhlAn2 and GraPhlAn were applied to analyze the sequencing data and visualize the microbial composition results, respectively. The microbes identified from the three soil samples belonged to 8 phyla, 14 classes, 21 orders, 32 families, 48 genera and 62 species. Among them, Pseudomonas was the dominant bacteria and Candida albicans was the dominant fungi. This discovery was consistent with the results from Liu Chunying, who has previously established some studies of Antarctic soil microorganisms. The bacterial abundance of S61 was the highest among the 3 samples and the dominant genus was Pseudomonas. Compared with bacterial species identified from S59 and S62, Janthinobacterium lividum, Pseudomonas veronii and Ralstonia were exclusive in S61. The relative abundance of bacteria and fungi in S59 was accounted for 59.83% and 39.92%, respectively. In which, Actinoplanes exclusively existed and Pseudomonas mandelii was the dominant bacterial species, while C. albicans was the dominant fungi species. The fungi abundance in S62 was slightly higher, which was about 58.13%. In this sample the dominant fungi was the same with S59 and the dominant bacteria was Pseudomonas. These results suggested us that the Antarctic had abundant microbial diversity and the species were distributed differently in different regions. The study of environmental microbial communities through metagenomic high-throughput sequencing provided supports for further investigations of metabolic potentials of microbiomes, in addition to their taxonomic composition. This greatly improved the ability to interpret and predict functional interactions and population dynamics of microbiomes.