Rubritalea spongiae sp nov and Rubritalea tangerina sp nov., two carotenoid- and squalene-producing marine bacteria of the family Verrucomicrobiaceae within the phylum 'Verrucomicrobia', isolated from marine animals

Two Gram-negative, non-motile, coccoid or rod-shaped, chemoheterotrophic bacteria designated strains YM21-132(T) and YM27-005(T) were isolated from marine animals, and were subjected to a polyphasic taxonomic examination. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the two isolates belong to the genus Rubritalea of the phylum 'Verrucomicrobia' (subdivision 1). The novel isolates shared approximately 97-98% sequence similarity with each other and showed 93-97% similarity with Rubritalea species of the family Verrucomicrobiaceae. The level of DNA-DNA relatedness between strains YM21-132(T) and YM27-005(T) was less than 70%, which is accepted as the phylogenetic definition of a species. Both strains produced reddish carotenoid pigments and squalene. The cell wall pepticloglycan of both strains contained muramic acid and meso-diaminopimelic acid. The G + C contents of the genomic DNA were 48.0 mol% (strain YM21-132(T)) and 50.3 mol% (strain YM27-005(T)). The presence of MK-8 and MK-9 as the major isoprenoid quinones, and iso-C-14:0, iso-C-16:0 and C(16:1)w omega 7c as the major cellular fatty acids supported the identification of the two novel strains as members of the genus Rubritalea. On the basis of polyphasic taxonomic studies, it was concluded that these strains should be classified as representing two novel, separate species in the genus Rubritalea within the phylum 'Verrucomicrobia', for which the names Rubritalea spongiae sp. nov. (type strain YM21-132(T) = MBIC08281(T) =KCTC 12906(T)) and Rubritalea tangerina sp. nov. (type strain YM27-005(T) = MBIC08282(T) =KCTC 12907(T)) are proposed.