Abstract
One gram-negative strain designated Bb-Pol-6 T was isolated from birch (Betula pendula) pollen at Giessen area, Germany. The analysis of 16S rRNA gene-based phylogenies indicated the next-relative genera were Robbsia, Chitinasiproducens, Pararobbsia and Paraburkholderia (96-95.6%). Further comparative genome analysis and phylogenetic tree-based methods revealed its phylogenetic position under the genus Robbsia. The genome of strain Bb-Pol-6 T was 5.04 Mbp with 4401 predicted coding sequences and a G + C content of 65.31 mol%. Average amino acid identity, average nucleotide identity, digital DNA-DNA hybridization and percentage of conserved proteins values to Robbsia andropogonis DSM 9511 T were 68.0, 72.5, 22.7 and 65.85%, respectively. Strain Bb-Pol-6 T was rod-shaped, non-motile, facultative anaerobic and grew optimally at 28 °C and pH 6-7. Ubiquinone 8 was the major respiratory quinone and the major cellular fatty acids were C16:0, C19:0 cyclo ω7c, C17:0 cyclo ω7c and C17:1 ω6c. The dominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and an unidentified aminophospholipid. Based on the genomic physiological and phenotypic characteristics, strain Bb-Pol-6 T was considered a novel species under the genus Robbsia, for which the name Robbsia betulipollinis sp. nov. was proposed. The type strain is Bb-Pol-6 T (= LMG 32774 T = DSM 114812 T).