A total of 36 bacterial and 25 fungal isolates E7080 were recovered from the South China Sea black coral A. dichotoma on the basis of their morphological differences. These bacterial and fungal isolates were identify by bacterial 16S rRNA gene sequences and fungal ITS sequences, respectively. By comparison with sequences in GenBank, the sequences of all isolates shared 99–100% similarity with their closest NCBI relatives, except that the fungal isolate SCSAAF0025 (JQ647904) shared 93% similarity with the known

fungal species Gliomastix murorum YNS1116–4 (JQ354930) in GenBank. These identified isolates (including 36 bacterial and 24 fungal isolates) were assigned to three bacterial phyla: Firmicutes (35%), Actinobacteria (23.3%) and Alphaproteobacteria (1.7%); and four fungal orders: Eurotiales (30%), Hypocreales (6.6%), Pleosporales (1.7%) and Botryosphaeriales (1.7%). Further phylogenetic analysis was carried out on 21 bacterial and 10 fungal representatives (belonging to 21 different bacterial and 10 different fungal species, respectively), which correspondingly showed similarity to 31 known authentic species of bacteria and fungi. The results

showed that the 21 bacterial representatives belonged to 21 species of eight genera (Fig. 2). Bacillus was the most diverse and common genus, with eight species and 16 isolates in the black coral A. dichotoma, followed by Streptomyces (5 species and 10 isolates) and Micromonospora (3 species and 3 isolates). The rest of the bacterial genera were rare, this website occurring as singletons. The phylogenetic NJ tree of partial ITS sequences of 10 fungal representatives is shown in Fig. 3. Seven fungal genera were recognized from the 10 fungal isolates. The most abundant and diverse fungi were observed in the genera Penicillium (3 species and 10 strains) and Aspergillus (2 species and 7 strains). Relatively highly abundant (3 strains) fungi were detected in the Unoprostone genus Fusarium. For the other four genera, only one isolate was found. Four different media were selected for bacterial isolation in this study.

The results showed that the number and genera of recovered bacterial isolates differed for the four media (Fig. 4). Bacteria could be recovered with all of the four media; M2 yielded the highest number of bacterial isolates and genera recovery with 14 isolates of seven genera. M3 had the least recoverability of bacterial isolates (only six isolates). The Bacillus and Streptomyces isolates were recovered from all four media. The genus Micromonospora could be only isolated from M2. The rest of the bacterial genera were isolated in very small numbers. Comparison of fungal isolates on four fungal isolation media showed that the number and genera of recovered fungal isolates also differed for the four types of media (Fig. 4). M6, M7 and M8 had the most and same recoverability of fungal genera (four genera for each media), whereas M5 yielded only two fungal genera.