题目：Diversity analysis of diazotrophs associated with corals from Xisha and Sanya,South China Sea.

作者: Qingsong Yang, Junde Dong*, Yanying Zhang, Juan Ling, Dongxiao Wang, Meilin Wu, Yufeng Jiang, Yuanzhou Zhang.

刊物: Aquatic Ecosystem Health & Management.

刊号: 2015,18(4):433-442

摘要: In recent years, many studies have shown an increase in coral associated microbial biodiversity in coral diseases. However, the variation of coral diazotroph, which plays an important role in the nitrogen cycle, is still unclear. To explore the changes of nitrogen fixing microbial communities, we analyzed the diversity of nitrogen-fixing bacteria associated with corals in healthy vs. diseased conditions, and corals from different locations (Xisha and Sanya). The diversity of nitrogen-fixing bacteria associated with two coral species, Porites lutea and Pocillopora damicornis was assessed using cloning and sequencing of the nitrogenase gene nifH. Phylogenetic analysis indicated coral associated diazotrophs community structure varied in different coral species: Chlorobi dominated in Porites lutea, while Alphaproteobacteria and Downloaded by [SDSU San Diego State University], [Yanying Zhang] at 14:23 22 September 2015 Gammaproteobacteria were the most abundant nitrogen-fixing bacteria in Pocillopora damicornis. The dominant group of nitrogen-fixing bacteria was Chlorobi in healthy Porites lutea, but Cyanobacteria predominated in diseased one. Moreover, the dominant nitrogen-fixing bacteria Gammaproteobacteria was replaced by Alphaproteobacteria in coral Pocillopora damicornis, from open sea to the coast. The diseased and coastal corals contained higher diversity of nitrogen-fixing bacteria than the healthy and open ocean corals. In conclusion, the nitrogen-fixing bacteria community structure shifted in response to the variation of coral species, coral health status and surrounding environments.