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

Abstract

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).