Abstract
Two Gram-negative non endospore-forming rod-like strains, designated C15T and C44, were isolated from the phyllosphere of Cerastium holosteoides and were studied in detail in order to assess their taxonomic position. 16S rRNA gene sequence analysis allocated both isolates clearly to the genus Methylobacterium. Both strains revealed the highest 16S rRNA gene sequence similarity to M. marchantiae JT1T (97.5%) and M. jeotgali 52/203-9T (97.4%). The fatty acids profiles contained major amounts of C16:0, C18:1 ω7c and C16:1ω7c/C15:0 iso 2-OH (summed feature 3), which supported the grouping of the isolates to the genus Methylobacterium. Physiological/biochemical characterisation and DNA-DNA hybridizations with the type strains of the most closely related species allowed a clear phenotypic and genotypic differentiation of the strains. For this reason, we propose for strain C15T (=DSM 23679T =CCUG 60040T =CCM 7788T ) a new species with the name Methylobacterium cerastii sp. nov. Strain C44 (=DSM 23675 =CCM 7789) is an additional strain of M. cerastii