Analysis of microbial communities on the coloured mantle surface of three common bivalves

Abstract

As economically significant species, bivalves maintain intimate contact with external microorganisms during respiration and filter feeding, rendering them prime candidates for investigating microbial communities. Although numerous studies have been conducted on the microbial communities inhabiting the mantles, the composition and functions of the microbial community residing within the coloured mantles remain unclear. The pigments in the coloured areas may attract some microorganisms related to pigments. Thus, in vitro culture can be utilized to rapidly assess the fundamental characteristics of the microbial community present in the coloured mantles. Our results indicated that the microbial community in the coloured mantles of three bivalves (Crassostrea gigas, Mytilus edulis, and Chlamys farreri) responded differently to various media, resulting in pigmentation occurring on tyrosine medium. Further analyses by Metabarcoding revealed a relatively low abundance of melanin-producing strains on the surface of coloured mantles, which may be related to the requirement of melanin-producing strains for a specific nutritional environment. Then, we observed that there were significant differences in the composition of the microbial communities in coloured mantles of the three bivalves, with different bivalves possessing distinct biomarkers. These microorganisms affect the host by regulating the immune system and aiding digestion, nutrient absorption, and nitrification. Correlation analysis showed that multiple metabolites of the three bivalves were strongly correlated with bacterial biomarkers and may play an important role in maintaining the dynamic balance of surface microbial communities. In conclusion, this study discussed the multifaceted effects of microorganisms on the dynamic equilibrium of bivalves microbial communities, exploring the intricate connection between the host and the microbe, as well as the composition of microbial communities. This lays the foundation for comprehending the intricate symbiotic relationship between bivalves and their microbial counterparts and offers a theoretical foundation for the future development of microbial preparations intended for bivalves body surfaces.

Keywords

• Microbial diversity
• Bivalve
• Coloration
• Mantles