Deep Insights into Gut Microbiota in Four Carnivorous Coral Reef Fishes from the South China Sea.

Yu-Miao Gao,Ke-Shu Zou,Lei Zhou,Xian-De Huang,Yi-Yang Li,Xiao Chen,Xiao-Yong Zhang,Xiang-Yang Gao

doi:10.3390/microorganisms8030426

Yu-Miao Gao, Ke-Shu Zou + Show 6 more

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https://doi.org/10.3390/microorganisms8030426

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Abstract

Investigations of gut microbial diversity among fish to provide baseline data for wild marine fish, especially the carnivorous coral reef fishes of the South China Sea, are lacking. The present study investigated the gut microbiota of four carnivorous coral reef fishes, including Oxycheilinus unifasciatus, Cephalopholis urodeta, Lutjanus kasmira, and Gnathodentex aurolineatus, from the South China Sea for the first time using high-throughput Illumina sequencing. Proteobacteria, Firmicutes, and Bacteroidetes constituted 98% of the gut microbiota of the four fishes, and 20 of the gut microbial genera recovered in this study represent new reports from marine fishes. Comparative analysis indicated that the four fishes shared a similar microbial community, suggesting that diet type (carnivorous) might play a more important role in shaping the gut microbiota of coral reef fishes than the species of fish. Furthermore, the genera Psychrobacter, Escherichia-Shigella, and Vibrio constituted the core microbial community of the four fishes, accounting for 61–91% of the total sequences in each fish. The lack of the genus Epulopiscium in the four fishes was in sharp contrast to what has been found in coral reef fishes from the Red Sea, in which Epulopiscium was shown to be the most dominant gut microbial genus in seven herbivorous coral reef fishes. In addition, while unique gut microbial genera accounted for a small proportion (8–13%) of the total sequences, many such genera were distributed in each coral reef fish species, including several genera (Endozoicomonas, Clostridium, and Staphylococcus) that are frequently found in marine fishes and 11 new reports of gut microbes in marine fishes. The present study expands our knowledge of the diversity and specificity of gut microbes associated with coral reef fishes.

Highlights

Coral reefs, the most diverse and productive marine ecosystems on earth, are recognized as the rainforests of the sea [1]
Rarefaction curves for the four fishes constructed for the number of observed microbial sequences vs. operational taxonomic units (OTUs) showed a plateau ranging from 40 to 70 (Figure 2), indicating that the number of the obtained sequences could sufficiently represent the diversity of the gut microbes in each fish species
The gut microbiota of four carnivorous coral reef fishes, O. unifasciatus, C. urodeta, L. kasmira, and G. aurolineatus, from the South China Sea were successfully characterized by high-throughput Illumina sequencing

Summary

Introduction

The most diverse and productive marine ecosystems on earth, are recognized as the rainforests of the sea [1]. It has been reported that coral reefs play a very important role in maintaining biodiversity and ecological balance of the oceans, they occupy less than 0.1% of the world’s ocean surface and provide complex and manifold marine habitats that support 25% of all marine species [2]. Most of the recent studies have mainly focused on investigating the diversity and distribution of coral reef fishes. Despite the unparalleled species diversity and population density of coral reef fish reported in recent decades [5], very little is known about their intestinal tract microbiology [6]

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