Paenihalocynthiibacter styelae gen. nov., sp. nov., isolated from stalked sea squirt Styela clava.

Abstract

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strain, MYP1-1T, was isolated from the intestine of a stalked sea squirt (Styela clava) of the South Sea in the Republic of Korea. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain MYP1-1T clustered with the type strains of Halocynthiibacter species and Pseudohalocynthiibacter aestuariivivens. Strain MYP1-1T exhibited 16S rRNA gene sequence similarity values of 97.0-97.6 % to the type strains of Halocynthiibacter namhaensis, Halocynthiibacter arcticus and P. aestuariivivens. The phylogenetic tree based on genomic sequences showed that strain MYP1-1T formed a distinct branch separating it from the type strains of two Halocynthiibacter species and P. aestuariivivens and other taxa. The DNA G+C content of strain MYP1-1T from its genomic sequence was 55.0 mol%. Strain MYP1-1T contained Q-10 as the predominant ubiquinone and C18 : 1 ω7c as the major fatty acid. The major polar lipids of strain MYP1-1T were phosphatidylcholine, phosphatidylglycerol, one unidentified lipid and one unidentified aminolipid. The differences in fatty acid and polar lipid profiles and other differential phenotypic properties made it reasonable to distinguish strain MYP1-1T from the genera Halocynthiibacter and Pseudohalocynthiibacter. On the basis of the polyphasic taxonomic investigations, we conclude that strain MYP1-1T constitutes a new genus and species within the class Alphaproteobacteria, for which the name Paenihalocynthiibacter styelae gen. nov., sp. nov. is proposed. The type strain is MYP1-1T (=KCTC 82143T=NBRC 114355T).