Rosenbergiella nectarea gen. nov., sp nov., in the family Enterobacteriaceae, isolated from floral nectar

Gram-negative, rod-shaped, oxidase-negative, facultatively anaerobic, yellow-orange-pigmented and motile bacterial strains, designated 8N4(T), 9N2 and 10N3, were isolated from flower nectar of Amygdalus communis (almond) and Citrus paradisi (grapefruit). The 16S rRNA gene sequences of the strains shared highest sequence similarity of 97.0% with that of Phaseolibacter flectens ATCC 12775(T) and lower similarity with sequences from other type strains of genera of the Enterobacteriaceae. A polyphasic approach that included determination of phenotypic properties and phylogenetic analysis based on 16S rRNA, gyrB, rpoB and atpD gene sequences supported the classification of strains 8N4(T), 9N2 and 10N3 within a novel species in a novel genus in the family Enterobacteriaceae. Strain 8N4(T), and the reference strains of the novel species, grew at 4-35 degrees C (optimum, 28-30 degrees C), with 0-5.0% NaCl (optimum, 3% NaCl) and with 0-60% sucrose (optimum, 10-25% sucrose). Their major cellular fatty acids were C-16:0, C-17:0 cyclo, C-18:1 omega 7c and summed feature 3 (C-16:1 omega 7c and/or iso-C-15:0 2-OH). The DNA G+C content of strain 8N4(T) was 46.8 mol%. On the basis of phenotypic properties and phylogenetic distinctiveness, the floral nectar isolates are classified within a novel species in a new genus in the family Enterobacteriaceae, for which the name Rosenbergiella nectarea gen. nov., sp. nov. is proposed. The type strain of Rosenbergiella nectarea is 8N4(T) (=LMG 26121(T)=DSM 24150(T)).