Abstract: To clarify the structure and function of sediment bacterial community in diseased areas of Apostichopus japonicus culture ponds, an experiment was conducted to examine the commonness and specificity of sediment bacterial community between diseased and normal areas in an A. japonicus culture pond by high-throughput sequencing. The results showed that there was no difference in the diversity of sediment bacterial community between diseased and normal areas, but richness was significantly lower in diseased areas (P<0.05). At the phylum level, Proteobacteria and Bacteroidetes were dominant bacteria in the sediments of the diseased and normal areas. The specific bacterial community in sediments of the diseased areas mainly belonged to Actinobacteria and Cyanobacteria, represented by Pseudoalteromonas, Vibrio, Staphylococcus, and Aliivibrio. The results of KEGG metabolic pathway annotation showed that there was significant difference for sediment bacterial communities in diseased and normal areas, with significant differences in 36 tertiary metabolic pathways (P<0.05), represented by significant upregulations in the pathways of glycosaminoglycan degradation, protein digestion and absorption, and various types of nitroglycan biosynthesis. Our results indicated that there were significant differences in the structure and function of sediment bacterial community in normal and diseased areas of A. japonicus  culture pond, and that the proliferation of opportunistic pathogens such as Vibrio, Pseudoalteromonas, and Staphylococcus increased the risk of A. japonicus suffering disease.

Key words: Apostichopus japonicus, culture pond, sediment bacterial community, high-throughput sequencing.