Report on microbial communities with gene functions and distribution of elements in Echinomuricea (Anthozoa: Holaxonia) from Thailand

Abstract

The genus Echinomuricea consists of marine invertebrates that are important to ocean ecosystems. The present study provided the first data on the microsymbiont community with microbial gene profiles and depositions of elements in gorgonian Echinomuricea cf. pulchra from parts of the western Gulf of Thailand. Among all the microbes identified, the bacterial diversity was the most abundant in gorgonian corals. The Vibrionaceae and Marinilabiliaceae were the predominant identified Gammaproteobacteria and Bacteroidetes, respectively. Of the other microbes, the Echinomuricea were dominated by the Mucorales for fungi, the Nitrosopumilales for Archaea and the Herpesvirales for viruses. In the gene prediction of coral microbial communities, replication, recombination, and repair were found mainly among the known function classes as the highest number of matched genes from the reference database of the evolutionary genealogy of genes: Non-Supervised Orthologous Groups. Kyoto Encyclopedia of Genes and Genomes pathway annotation showed a high number of genes related to transport and the catabolism of cellular processes; signaling molecules; and the interactions of environmental information processing, translation, folding, sorting and the degradation of genetic information processing. From the Carbohydrate-Active Enzyme database, glycoside hydrolases, carbohydrate-binding modules and glycosyltransferases predominated in these functional classes. Scanning electron microscopy using an energy-dispersive X-ray identified calcium throughout the sclerites of coenenchyma, but this element was rarely distributed on the axis of corals. Oxygen and nitrogen were observed in all surface fragments, while the magnesium signal was low. Based on these results, this was the first report of a meta-analysis of microbiota with the main elements of Echinomuricea surfaces. These data might support the understanding of microbial symbionts associated with E. cf. pulchra.