Pangenome- and genome-based taxonomic classification inference for the marine bacterial strain KMM 296 producing a highly active PhoA alkaline phosphatase and closely relatedCobetiaspecies

Abstract

AbstractA strictly aerobic, Gram-stain-negative, rod-shaped and motile bacterium, designated strain KMM 296, isolated from the coelomic fluid of musselCrenomytilus grayanus, was investigated in details due to its ability to produce a highly active alkaline phosphatase of the structural family PhoA. A previous taxonomic study placed the strain to the speciesCobetia marina, a member of the familyHalomonadaceaeof the classGammaproteobacteria. However, the comprehensive phylogenetic analysis based on 16S rRNA gene sequencing revealed that the strain KMM 296 is most closely related toCobetia amphilectiNRIC 815Twith the 16S rRNA gene sequence similarity of 100%. The mussel isolate grew with 0.5-19% NaCl and at 4 - 42°C and hydrolysed Tweens 20 and 40, and L-tyrosine. The DNA G+C content was 62.5 mol%. The prevalent fatty acids were C18:1ω7c, C12:03-OH, C18:1ω7c, C12:0and C17:0cyclo. The polar lipid profile was characterized by the presence of phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, and unidentified aminolipid, phospholipid, and lipids. The major respiratory quinone was Q-8. According to phylogenetic evidence and similarity in the chemotaxonomic and genotypic properties of the mussel isolate and its nearest neighbors, the strain KMM 296 represents a member of the speciesC. amphilecti. A comparative analysis of the type strains genomes of the speciesC. amphilectiandC. litoralisshowed that they belong to a single species. In addition, a high similarity of the genome sequences ofC. pacificaNRIC 813TandC. marinaLMG 2217Talso allows suggesting the affiliation of these two species to one species. Based on the rules of priority,C. litoralisshould be reclassified as a later heterotypic synonym ofC. amphilecti, andC. pacificais a later heterotypic synonym ofC. marina. The emended descriptions of the speciesC. amphilectiandC. marinaare also proposed.