Robbsia betulipollinis sp. nov., Isolated from Pollen of Birch (Betula pendula)

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 cycloω7c, C17:0 cycloω7c and C17:1ω6c. 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).

Is the plant microbiome transmitted from pollen to seeds?

“…In the last few years, the diversity, structure, and co-occurrence network of the pollen microbiome associated with different plant species, both wind-pollinated and insect-pollinated, have been investigated in a few observational studies (Ambika Manirajan et al, 2016 , 2018a , b ; Obersteiner et al, 2016 ). A remarkably vast fungal and bacterial diversity in pollen was shown, which also included new bacterial species, such as Spirosoma pollinicola from Corylus avellana (Ambika Manirajan et al, 2018b ) and Robbsia betulipollinis from Betula pendula (Shi et al, 2023 ), and even a new genus, Saccharibacter , from Japanese flowers (Jojima et al, 2004 ). Moreover, a high level of species-specificity was shown.…”

Pollen Partners: The Symbiotic Microbes ofPinus radiataPollen

“…At the genera level, Robbsia, Sphingomonas, Hymenobacter, Acidisoma and Methylobacterium were the dominant genera of the core bacterium community. Of these, Robbsia and Methylobacterium have been found on birch and canola pollen previously (Shi et al, 2023;Manirajan et al, 2018), and Sphingomonas are well documented as a core bacterium via in pollen collected by bees (Dew et al, 2020). Methylobacterium are a genus of well-documented phyllosphere epiphytes that secrete cytokinins and auxin plant hormones (Sanjenbam et al, 2022).…”