Diversity and network analysis of culturable bacteria on stalactite sediment in Zhijin cave

Abstract:

[Background] There are abundant bacterial resources in the cave environment. The isolation and cultivation of bacteria in the cave helps for the understanding bacterial diversity, as well as the exploration and utilization of bacterial resources. [Objective] To isolate the bacteria by using different media, and to explore the diversity and interactions of cultivable bacteria on the stalactite surface in cave. [Methods] Totally, 11 kinds of media were used to isolate and purify the bacteria, then the taxonomic position of the isolates was preliminarily determined by analysis of their 16S rRNA gene sequence. Additionally, bipartite packet was used to analyze the interaction among the culturable bacteria under R environment. [Results] A total of 206 strains of bacteria were isolated from the samples. These bacteria belonged to 45 species of 4 genera and 25 genera in community with the Shannon index of 4.78 and the Simpson index of 0.95. Proteobacteria and Bacillus are the dominant phylum (47.09%) and genus (29.61%), respectively. The inorganic oligotrophic media were helpful for the isolation of bacteria from stalactite sediments in the cave. Based on genus level-sampling site network analysis shows that the distribution of culturable bacteria has a non-random and significant nestedness community. Bacillus, Devosia, Alcaligenes, Arthrobacter, and Brevibacterium with more effective cooperation and closeness in community are highly dependent on other bacteria, and are the key groups in the community. [Conclusion] There are abundant bacterial resources on the surface of stalactite sediments in Zhijin cave. The relative abundance and network analysis of different groups should be combined to determine the role of bacteria in communities.

Key words:stalactite, sediment, culturable bacteria, diversity, Zhijin cave, network analysis, oligotrophic