Terricaulis silvestris gen. nov., sp. nov., a novel prosthecate, budding member of the family Caulobacteraceae isolated from forest soil

The family Caulobacteraceae comprises prosthecate bacteria with a dimorphic cell cycle and also non-prosthecate bacteria. Cells of all described species divide by binary fission. Strain 0127_4 T was isolated from forest soil in Baden Württemberg (Germany) and determined to be the first representative of the family Caulobacteraceae which divided by budding. Cells of strain 0127_4 T were Gram-negative, rod-shaped, prosthecate, motile by means of a polar flagellum, non-spore-forming and non-capsulated. The strain formed small white colonies and grew aerobically and chemo-organotrophically utilizing organic acids, amino acids and proteinaceous substrates. 16S rRNA gene sequence analysis indicated that this bacterium was related to Aquidulcibacter paucihalophilus TH1-2 T and Asprobacter aquaticus DRW22-8 T with 91.3 and 89.7% sequence similarity, respectively. Four unidentified glycolipids were detected as the major polar lipids and, unlike all described members of the family Caulobacteraceae , phosphatidylglycerol was absent. The major fatty acids were summed feature 8 (C 18 : 1 ω7 c /C 18 : 1 ω6 c ), summed feature 9 (iso-C 17 : 1 ω9 c /C 16 : 0 10-methyl), C 16 : 0 and summed feature 3 (C 16 : 1 ω 6 c /C 16 : 1 ω 7 c ). The major respiratory quinone was Q-10. The G+C content of the genomic DNA was 63.5 %. Based on the present taxonomic characterization, strain 0127_4 T represents a novel species of a new genus, Terricaulis silvestris gen. nov., sp. nov. The type strain of Terricaulis silvestris is 0127_4 T (=DSM 104635 T =CECT 9243 T ).