Alterisphingorhabdus coralli gen. nov. sp. nov., a novel aerobic anoxygenic phototrophic bacteria isolated from reef-building coral

The photosynthetic microorganisms within the coral holobiont produce energy and organic compounds through photosynthesis, which are vital for the biocalcification and heat tolerance of coral hosts. However, aerobic anoxygenic phototrophic bacteria (AAPB), which are one of the most important photosynthetic microorganisms, have not been thoroughly investigated in this environment. In this study, a novel AAPB, SCSIO 66989T, was isolated from the reef- building coral Favia sp. and considered a beneficial microorganism for corals (BMC). The polyphasic taxonomic analysis showed that it had the highest similarities with Parasphingorhabdus litoris DSM 22379T (95.9%) and Altererythrobacter ishigakiensis ATCC BAA2084T (95.7%). Phylogenetic analysis showed that it formed an independent clade, distinguishing it from other genera within the family Sphingomonadaceae. The predominant fatty acids were C 18: 1 omega 7 c and/or C 18: 1 omega 6 c and C 16:0 . The major respiratory quinone was ubiquinone-10 (Q- 10). Sphingolipid, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine were the diagnostic polar lipids. The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values between SCSIO 66989T and the type strains of P. litoris DSM 22379T and A. ishigakiensis ATCC BAA-2084T were 69.2-70.0%, 58.6-61.2% and 19.2-19.7%, respectively. These results indicate that strain SCSIO 66989T represents a new species of a novel genus in the family Sphingomonadaceae, for which the name Alterisphingorhabdus coralli gen. nov. sp. nov. is proposed.