Comparative analysis of bacterial community diversity between soil and water of Dongzhai Harbor Mangrove reserve using 16S rRNA gene sequencing and shotgun metagenomic sequencing

Abstract The mangrove ecosystem has rich biological resources and is the fourth highest service value ecosystem in the world. The Dongzhai Harbor Mangroves (DHM) reserve is located in the intertidal zone where the freshwater and seawater are dynamically interlaced, and its unique habitat may hide special microbial resources. In this study, we analyzed and compared bacterial community composition and diversity between the DHM soil and water by 16S rRNA gene sequencing and shotgun metagenomic sequencing. We found that the dominant species in both soil and water of DHM were Proteobacteria and Actinobacteria, while the most differentially abundant species were Chloroflexi and Bacteroidetes. However, shotgun metagenomic sequencing analysis identified more highly abundant species in the water than in the soil, and identified more species with significant differences between the soil and the water (P ≤ 0.0001). Network analysis identified more co-occurring species in the soil and water. Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analysis identified three relatively abundant pathways: metabolism (accounting for more than 50%), genetic information processing, and environment information processing. Our results increase our understanding of bacterial community diversity in the water and soil of the DHM. Additional information that is hidden in the environment may be obtained by shotgun metagenomic sequencing; this technique can be used to mine more microbial resources from various environments.