Splendidivirga corallicola gen. nov., sp. nov. and Agaribacillus aureus gen. nov., sp. nov., two bacteria isolated from coral Porites lutea , and proposal of Splendidivirgaceae fam. nov.

The Bacteroidota is one of the dominant bacterial phyla in corals. However, the exact taxa of those coral bacteria under the Bacteroidota are still unclear. Two aerobic, Gram-stain-negative, non-motile rods, designated strains BMA10 ^T and BMA12 ^T , were isolated from stony coral Porites lutea collected from Weizhou Island, PR China. Global alignment of 16S rRNA gene sequences indicated that both strains are closest to species of Fulvivirga with the highest identities being lower than 93 %, and the similarity value between these two strains was 92.3 %. Phylogenetic analysis based on 16S rRNA gene and genome sequences indicated that these two strains form an monophylogenetic lineage alongside the families Fulvivirgaceae , Reichenbachiellaceae , Roseivirgaceae , Marivirgaceae , Cyclobacteriaceae , and Cesiribacteraceae in the order Cytophagales , phylum Bacteroidota . The genomic DNA G+C contents of BMA10 ^T and BMA12 ^T were 38.4 and 41.9 mol%, respectively. The major polar lipids of BMA10 ^T were phosphatidylethanolamine, unidentified aminophospholipid, four unidentified aminolipids, and five unidentified lipids. While those of BMA12 ^T were phosphatidylethanolamine, two unidentified aminolipids, and five unidentified lipids. The major cellular fatty acids detected in both isolates were iso-C _15 : 0 and C _16 : 1  ω 5 c . Carbohydrate-active enzyme analysis indicated these two strains may utilize coral mucus or chitin. Based on above characteristics, these two strains are suggested to represent two new species in two new genera of a new family in the order Cytophagales , for which the name Splendidivirga corallicola gen. nov., sp. nov., Agaribacillus aureus gen. nov., sp. nov. and Splendidivirgaceae fam. nov. are proposed. The type strain of S. corallicola is BMA10 ^T (=MCCC 1K08300 ^T =KCTC 102045 ^T ), and that for A. aureus is BMA12 ^T (=MCCC 1K08309 ^T =KCTC 102046 ^T ).