Coral reef ecosystems usually distribute in oligotrophic tropical and subtropical marine environments, but they possess great biodiversity and high productivity. It may attribute to its efficient internal nutrient cycle system. However, the knowledge of functional microbial community structure is still limited. In this study, both functional gene array (Geochip 5.0) and nifH Illumina sequencing were used to profile the overall functional genes and diazotrophic communities associated with coral Porites pukoensis. More than 7500 microbial functional genes were detected from archaea, bacteria, and fungi. Most of these genes are related to the transformation of carbon, nitrogen, sulfur, and phosphorus, providing evidence that microbes in the coral holobiont play important roles in the biogeochemical cycle of coral reef ecosystems. Our results indicated a high diversity of diazotrophs associated with corals. The dominant diazotrophic groups were related to phyla Alphaproteobacteria, Deltaproteobacteria, Cyanobacteria, and Gammaproteobacteria. And the dominant diazotrophic communities were divided into four clusters. They were affiliated with nifH sequences from genera Zymomonas, Halorhodospira, Leptolyngbya, Trichormus, and Desulfovibrio, indicating these groups may play a more important role in the nitrogen-fixing process in the coral holobiont. This study revealed functional gene diversity and suggested the roles they played in the biogeochemical cycling of the coral holobiont.

珊瑚礁生态系统通常分布在贫营养的热带和亚热带海洋环境中，但它们拥有丰富的生物多样性和高生产力。它可能归因于其有效的内部养分循环系统。但是，功能微生物群落结构的知识仍然有限。在这项研究中，这两种功能的基因阵列（Geochip 5.0）和nifH Illumina测序被用于配置文件与珊瑚相关的总体功能性基因和固氮社区滨pukoensis。从古细菌，细菌和真菌中检出了7500多种微生物功能基因。这些基因中的大多数与碳，氮，硫和磷的转化有关，这提供了证据表明珊瑚全生物中的微生物在珊瑚礁生态系统的生物地球化学循环中起着重要作用。我们的结果表明，与珊瑚有关的重氮营养菌具有很高的多样性。占主导地位的重氮营养族群与门阿尔法氏菌，德尔塔氏菌，蓝藻和丙酸杆菌有关。占主导地位的重氮营养群落被分为四个集群。它们与Zymomonas属，Halohodospira，Leptolyngbya，Trichormus属的nifH序列相关。，和Desulfovibrio，表明这些基团可能在珊瑚整体生物的固氮过程中起着更重要的作用。这项研究揭示了功能基因的多样性，并暗示了它们在珊瑚礁生物的生物地球化学循环中所起的作用。