The Study of Microbial Diversity in Mangrove Wetland Ecological System Based on a 16S rDNA Library

Abstract

The microbial resources in mangrove wetland ecological system are abundant because of their special characteristics. However traditional methods of isolation and culture alone cannot analyze the microbial diversity fully and so, in this study, a 16S rDNA library was constructed to analyze microbial diversity in the Fugong mangrove of the Jiulong River Estuary, Fujian Province, China. The total sediment DNA was extracted, a 16S rDNA library constructed, and the clones analyzed using the restriction fragment length polymorphism (RFLP) method. The 16S rDNA sequences of 50 clones which had a higher display frequency in the RFLP analysis were blasted with the sequences in GenBank. The results showed that the highest similarity of the sequence in clones was 100%, while the lowest was 88%. The dominant microbes from mangrove sediments in the 16S rDNA library belonged to the Proteobacteria (70%) including α-proteobacteria (6.0%), γ-proteobacteria (22.0%), δ-proteobacteria (10.0%) and ε-proteobacteria (32.0%). The other microbes were Bacteroidetes (8.0%), Planctomycetacia (2.0%), Actinobacteria (2.0%) and Verrucomicrobia (2.0%). Additional uncultured microorganisms as well as those whose classification information was unclear were also detected (16.0%). The results of this study indicated that more objective and comprehensive information of microbial diversity in mangrove wetland ecological system had been obtained. There is abundant microbial diversity and a large amount of unknown microbial resources in mangrove wetland ecological system, which could have a very important potential, and so there should be more research to explore and utilize these microbial and functional gene resources in mangrove wetland ecological system.