Metagenomics Unveils Posidonia Oceanica "Banquettes" as a Potential Source of Novel Bioactive Compounds and CAZymes
Background Posidonia oceanica is a long-living and very slow-growing marine seagrass endemic to the Mediterranean Sea. It produces large amounts of leaf material and rhizomes, which can reach the shore and build important banks known as "banquettes". In recent years, interest in the potential uses of these P. oceanica banquettes has increased and it was demonstrated that biomass extracts showed antioxidant, antifungal, and antiviral activities. The discovery of new compounds through the culture
... through the culture of microorganisms is limited, and to overcome this limitation, a metagenomic study was performed to investigate the microbial community associated with P. oceanica banquettes. Results The microbial community associated with P. oceanica banquettes was dominated by Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes and Cyanobacteria. Pseudoalteromonas was the most abundant genus, followed by Alteromonas , Labrencia, and Aquimarina . The metagenome reads were binned and assembled into 23 near-complete metagenome-assembled genomes (MAGs), which belonged to new families of Cyanobacteria, Myxococcota and Granulosicoccaceae and also to the novel genus recently described as Gammaproteobacteria family UBA10353. A comparative analysis with 60 published metagenomes from different environments, including seawater, marine biofilms, soils, corals, sponges and hydrothermal vents, indicated that banquettes have numbers of natural products and Carbohydrate-Active Enzymes (CAZymes) similar to those found for soils and were only surpassed by marine biofilms. New condensation (C) domains in multi-enzymatic non ribosomal peptide synthetases (NRPS) solely found in P. oceanica banquettes were recovered; 90 of the 181 found lacked known homologues. Furthermore, new proteins assigned to cellulosome modules and lignocellulose-degrading enzymes were also found. Conclusions Our results unveiled the diverse microbial composition of P. oceanica banquettes and determined that banquettes are a potential source of bioactive compounds and novel enzymes.