Fig. 4

Class-level taxonomic composition of chitinolytic microbial communities across marine biotopes. Microbial metagenome mining and assignment of chitinase-encoding genes were performed on unassembled metagenome samples of seawater, marine sediments, octocorals, and marine sponges. Panels (a and b) represent the octocoral metagenome dataset (project PRJEB13222 [28] and the sponge metagenome dataset (project PRJEB11585 [27], respectively. Putative endo-chitinase nucleotide sequences were retrieved from both datasets using the MG-RAST metagenomics analysis platform [30] and then subjected to a stringent NCBI blastx search for taxonomic and functional assignments. Only those sequence reads which returned chitinases as closest hits and could be assigned to bacterial taxa after NCBI blastx procedures were used in taxonomic profiling. E. gazella_H—healthy Eunicella gazella tissue; E. gazella_NEC—necrotic Eunicella gazella tissue. For genus-level taxonomic profiling of sponge and octocoral samples, see Additional file S1: Table S7