Marinicella marina sp. nov. and Marinicella gelatinilytica sp. nov., isolated from coastal sediment, and genome analysis and habitat distribution of the genus Marinicella

Three Marinicella strains, X102, S1101(T) and S6413(T), were isolated from sediment samples from different coasts of Weihai, PR China. All strains were Gram-stain-negative, rod-shaped and non-motile. The predominant fatty acids of all strains were iso-C-15:0 and summed feature 3 (C-16:1 omega 7c/C-16:1 omega 6c) and the major polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Strains X102 and S1101(T) shared 100 % 16S rRNA gene sequence similarity, and strains S1101(T)/X102 and S6413(T) had 95.4% similarity. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strains S1101T and X102 were 99.9 and 99.2%, respectively. Strain S1101(T) had ANI values of 69.1-72.9% and dDDH values of 17.9-20.5% to members of the genus Marinicella. Strain S6413(T) had ANI values of 69.1-77.5% and dDDH values of 17.6-21.5 % to members of the genus Marinicella. The results of phylogenetic and comparative genomic analysis showed that the three strains belong to two novel species in the genus Marinicella, and strains X102 and S1101(T) represented one novel species, and strain S6413(T) represented another novel species. The result of BOX-PCR and genomic analysis showed that X102 and S1101(T) were not the same strain. The phylogenetic analyses and genomic comparisons, combined with phylogenetic, phenotypic and chemotaxonomic features, strongly supported that the three strains should be classified as representing two novel species of the genus Marinicella, for which the names Marinicella marina sp. nov. and Marinicella gelatinilytica sp. nov. are proposed, respectively. The type strains of the two novel species are S1101(T) (=KCTC 92642(T)=MCCC 1H01359(T)) and S6413(T) (=KCTC 92641(T)=MCCC 1H01362(T)), respectively. In addition, all previously described isolates of Marinicella were isolated from marine environments, but our study showed that Marinicella is also distributed in non-/low-saline habitats (e.g. animal gut, soil and indoor surface), which broadened our perception of the environmental distribution of Marinicella.