Metagenomes of the Dominant Microbial Symbionts of Sponge Genus Cinachyrella Display Common Sulfur Metabolic and Quorum Sensing Functions.

Host associated microbes play important roles in animal health. The symbiotic relationship between sponges and the microorganisms, prokaryotes-in particular, forms a complex mutualistic system, or community called the “microbiome”. Prokaryotes play a dynamic roll in these symbioses including providing nutritional sources, digestion, development, metabolism, immune defenses, while host sponge provides an environment for the symbionts. However, the whole metabolism of a sponge, holobioint, and the symbiont diversity and respective contributions to the holobtiont remains unclear. Metagenomics is an approach to study these systems by analyzing the gene content of the microorganisms for both taxonomic affiliation and biochemical function. The primary objective of this study is to describe local reef sponge Cinachyrella microbiome diversity, composition, and functional roles they occupy. Sponge metagenome sequences were assembled and binned into twenty-six high-quality Metagenomically Assembled Genomes (MAGs) and were taxonomically and functionally characterized. These two MAGs have been identified as Ardenticatena (Phylum Chloroflexi), and Thioalkalivibrio (Phlyum Proteobacteria). The MAG characterization includes inter/intraspecific diversity, composition, and functional roles they occupy. These two MAGs represent over 20% abundance of all sequence reads, suggesting their important functions for the holobiont. A MAG matching Thioalkivibrio has been shown to occur in other sponge symbioses. Conserved function in several genomes included quorum sensing and sulfur metabolism