Abstract:To investigate the structure and function of the bacterial community in Apostichopus japonicus (sea cucumber) culture ponds in Changhai, North China, the bacterial community composition and diversity were seasonally analyzed by high-throughput sequencing and bioinformatics analysis. The results showed that the bacterial richness and diversity were the highest in the summer and the lowest in the autumn. In all seasons, the predominant phylum was Proteobacteria, followed by Bacteroidetes, but higher levels of other bacterial phyla were observed in the spring (Verrucomicrobia), summer (Actinobacteria), and winter (Firmicutes). There were no significant differences in the phyla of autumn with that of other seasons. Predictive functional profiling based on the Clusters of Orthologous Groups of proteins (COGs) database (functional codes denoted by [X]) showed significant differences (P<0.05) in 24 aquatic bacterial community proteins. In spring and winter, the proteins for energy production and conversion; nucleotide transport and metabolism; carbohydrate transport and metabolism; secondary metabolite biosynthesis, transport, and catabolism; cell wall/membrane/envelope biogenesis; cell motility; transcription; and replication, recombination, and repair were significantly upregulated. Proteins regulating carbohydrate transport and metabolism; translation, ribosomal structure, and biogenesis; and cell wall/membrane/envelope biogenesis were significantly downregulated in summer. In autumn, the proteins regulating cell cycle control, cell division, and chromosome partitioning; cytoskeleton; and secondary metabolite biosynthesis, transport, and catabolism were significantly downregulated, and the proteins for extracellular structures were upregulated. These results indicate that the richness and diversity of the bacterial community in the sea cucumber culture pond are the lowest in autumn and that seasonal changes in the community structure depend on the function. This study provides a theoretical basis for water microecology regulation and the prevention and control of A. japonicus diseases.
