Roseicyclus amphidinii sp. nov., a novel bacterium isolated from the culture of a dinoflagellate Amphidinium carterae

A Gram-negative, rod-shaped and light pink-pigmented bacterial strain, designated Amp-Y-6 T , was isolated from the culture of a dinoflagellate Amphidinium carterae CCMP1314. It can produce bacteriochlorophyll a . The 16S rRNA gene of strain Amp-Y-6 T had the highest sequence similarity with Roseicyclus marinus CCMM001 T of 98.1%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain Amp-Y-6 T was affiliated to the genus Roseicyclus and formed a monophyletic clade with R. marinus CCMM001 T and Roseicyclus mahoneyensis ML6 T . The digital DNA–DNA hybridization, average nucleotide identity and average amino acid identity between strain Amp-Y-6 T and the two phylogenetic relatives were 22.7–22.8, 80.4–80.5 and 79.5–80.2%, respectively. The respiratory quinone was Q-10. The major fatty acid composition was summed feature 8 (C 18:1 ω7c and/or C 18:1 ω6c ). The draft genome size was 3.8 Mbp with a genomic G+C content of 68.1 mol%. Gene annotation showed that Amp-Y-6 T contained a gene cluster responsible for the C-P degradation, indicating that it had the potential to provide a phosphate source for the dinoflagellate. Based on the phylogenetic, phenotypic and chemotaxonomic characteristics, strain Amp-Y-6 T represents a novel species, for which the name Roseicyclus amphidinii sp. nov. is proposed. The type strain is Amp-Y-6 T (=MCCC 1K08249 T =KCTC 92882 T ).