Sulfitobacter pseudonitzschiae sp. nov., isolated from the toxic marine diatom Pseudo-nitzschia multiseries
A taxonomic study was carried out on bacterial strain H3T, which was isolated from the toxic marine diatom Pseudo-nitzschia multiseries. Cells of strain H3T were Gram-stain-negative, rod-shaped, non-motile and capable of reducing nitrate to nitrite, but not denitrification. Growth was observed at NaCl concentrations of 1–9 %, pH 6–12 and 10–37 °C. It was unable to degrade aesculin or gelatin. The dominant fatty acids (>10 %) were C18 : 1ω7c/ω6c (summed feature 8) and C16 : 0. The respiratory ubiquinone was Q10. The major lipids were phosphatidylethanolamine, phosphatidylglycerol, an aminolipid and one unknown lipid, and the minor lipids were two phospholipids and three unknown lipids. The G+C content of the chromosomal DNA was 61.7 mol%. 16S rRNA gene sequence comparison showed that strain H3T was related most closely to Sulfitobacter donghicola DSW-25T (97.3 % similarity) and levels of similarity with other species of the genus Sulfitobacter were 95.1–96.9 %. The mean (±sd) DNA–DNA hybridization value between strain H3T and Sulfitobacter donghicola DSW-25T was 18.0±2.25 %. The average nucleotide identity between strain H3T and Sulfitobacter donghicola DSW-25T was 70.45 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain H3T formed a separate clade close to the genus Sulfitobacter and was distinguishable from phylogenetically related species by differences in several phenotypic properties. On the basis of the phenotypic and phylogenetic data, strain H3T represents a novel species of the genus Sulfitobacter , for which the name Sulfitobacter pseudonitzschiae is proposed (type strain H3T = DSM 26824T = MCCC 1A00686T).