Microbiota Diversity in Pearl Oyster Pinctada fucata martensii Intestine and Its Aquaculture Environment

Abstract

Environmental microbiota plays a vital role in the intestinal microbiota of aquatic organisms. However, data concerning the association between the intestinal microbiota of pearl oyster Pinctada fucata martensii and the surrounding seawater are limited. The existing bacterial communities in pearl oyster intestine and surrounding water from two sites (D and H, within Liusha Bay in Guangdong, China) were investigated using 16S rRNA-based sequencing to explore the relationship among the two. D located in the inner bay, and H located in the open sea area outside bay. Results revealed the richness and diversity of pearl oyster intestinal microbiota to be less than those of the surrounding water, with 38 phyla and 272 genera observed as a result of the classifiable sequence. The microbiota compositions in the intestine and the surrounding water were diversified at the phylum and genus levels, with the sequencing data being statistically significant. However, the functional prediction of microbiota emphasized the overall similarity in the functional profile of the surrounding seawater and intestinal microbiomes. This profile was associated with metabolism of cofactors and vitamin, carbohydrates metabolism, amino acids metabolism, metabolism of terpenoids, and polyketides, metabolism of other amino acids, lipids metabolism, and energy metabolism. Seven common operational taxonomic units (OTUs), which belonged to phyla Tenericutes, Cyanobacteria, and Planctomycetes, were noted in the intestines of pearl oysters from two different sites. These OTUs may be affiliates to the core microbiome of pearl oyster. Significantly different bacterial taxa in the intestines of pearl oysters from two different sites were found at the phylum and genus levels. This finding suggested that the bacterial communities in pearl oyster intestines may exhibit some plasticity to adapt to changes in the surrounding water-cultured environment. This study generally offers constructive discoveries associated with pearl oyster intestinal microbiota and provides guidance for sustainable aquaculture.

Pearl Oyster Bacterial Community Structure Is Governed by Location and Tissue-Type, but Vibrio Species Are Shared Among Oyster Tissues

“…The pearl oyster large intestinal tissue was remarkably different from all other tested tissue types and was dominated by an uncultured family in the Planctomycetales . In agreement with our data, Planctomycete bacteria have been identified as dominant members within the intestinal and gut environment in many bivalve species including pearl oysters ( Dubé et al, 2019 ; Zheng et al, 2021 ). In our study, the dominant genus Blastopirellula is in the family Pirellulaceae , members of which are dominant in pearl oyster alimentary tissue ( Dubé et al, 2019 ).…”

“…The lack of association with water at each farm also supports the unique nature of the microbial communities in oyster tissues. The dominance of the Cyanobiaceae genus Synechococcus in both oyster tissue type and farm water has been reported elsewhere including in the pearl oyster intestine and surrounding water environment ( Zheng et al, 2021 ). The higher relative abundance of the Rhodobacteraceae family in the shell swab samples relative to the pearl oyster tissues samples suggests the preferential colonization of these species on the shell.…”

“…The higher relative abundance of the Rhodobacteraceae family in the shell swab samples relative to the pearl oyster tissues samples suggests the preferential colonization of these species on the shell. This family included the genera Nautella and Ruegeria reported in other pearl oyster species ( Zheng et al, 2021 ) and members of the genus Ruegeria can produce the broad-spectrum antibiotic tropodithietic acid ( Beyersmann et al, 2017 ). The dominance in the shell microbiome supports their reported ability to rapidly colonize surfaces and produce antibacterial components, preventing other bacteria from growing ( Arfken et al, 2017 ).…”

“…Vibrios have been implicated in pearl oyster diseases internationally ( Wang et al, 2016 ), including Australia ( Negri et al, 2004 ), and were reported in low abundance in the P. margaritifera ( Dubé et al, 2019 ) and P. fucata martensii bacterial communities ( Zheng et al, 2021 ). It is still not clear what factors govern bacterial assemblage structure within the pearl oyster and to what extent putative pathogens, including Vibrios , influence pearl oyster health and productivity.…”

16S rRNA–Based Analysis Reveals Differences in the Bacterial Community Present in Tissues of Choromytilus chorus (Mytilidae, Bivalvia) Grown in an Estuary and a Bay in Southern Chile

“…Hueihue Bay is located in the Chiloe Island archipelago, which is an area with high industrial activity focused on intensive aquaculture (salmon and bivalve industry); therefore, the occurrence of pollutantdegrading bacteria in the microbiota of C. chorus from Hueihue Bay might be related to greater urbanization and anthropogenic influence in this region that in the Nehuentue estuary, which is less urbanized and where the main activities are related to tourism and artisanal fisheries. In addition, other functions were inferred, such as nitrate reduction, fermentation, phototrophy, and photoautotrophy, which have also been reported in other bivalves [69,70]. However, more studies on the roles of microbiota in hosts and in maintaining water quality in both locations are required to confirm this statement.…”