Cerasicoccus maritimus sp. nov. and Cerasicoccus frondis sp. nov., two peptidoglycan-less marine verrucomicrobial species, and description of Verrucomicrobia phyl. nov., nom. rev.

摘要

Three Gram-negative, pale-pink-pigmented, spherical, chemoheterotrophic bacteria were isolated from seawater and a dystrophic leaf in the Republic of Palau. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the novel isolates YM31 -114~T, YM31 -066~T and YM31 -067 shared approximately 97-100% sequence similarity with members of the genus Cerasicoccus of the family Puniceicoccaceae within the phylum 'Verrucomicrobia.' The hybridization values for DNA-DNA relatedness between the novel isolates and Cerasicoccus arenae YM26-026~T were less than 70%, which is accepted as a phylogenetic definition of a species. β-Lactam antibiotic susceptibility test and amino acid analysis of cell-wall hydrolysates revealed that the novel isolates did not contain muramic acid or diaminopimelic acid in their cell walls, suggesting that these strains lack peptidoglycan. The DNA G+C contents of the three strains were 55-56 mol%; MK-7 was the major menaquinone. The presence of C_(14:0) and C_(18:1)ω9c as the major cellular fatty acids supported the identification of the novel isolates as members of the genus Cerasicoccus. On the basis of polyphasic taxonomic evidence, it was concluded that these strains should be classified as representing two novel, separate species in the genus Cerasicoccus within the phylum 'Verrucomicrobia,' for which the names Ceras/coccus maritimus sp. nov. (type strain YM31-114~T=MBIC24844~T) and Ceras/coccus frondis sp. nov. (type strain YM31-066~T=MBIC24796~T) are proposed. Proposal for designation of the Verrucomicrobia phyl. nov., nom. rev. is also presented.