Bombella pluederhausensis sp. nov., Bombella pollinis sp. nov., Bombella saccharophila sp. nov. and Bombella dulcis sp. nov., four Bombella species isolated from the environment of the western honey bee Apis mellifera

Abstract

Four strains of members of the genus Bombella were isolated from samples associated with the western honey bee Apis mellifera, which could not be assigned to a species with a validly published name. Strains TMW 2.2543T, TMW 2.2556T, TMW 2.2558T and TMW 2.2559T exhibit in silico DNA–DNA hybridisation (isDDH) and orthologous average nucleotide identity (orthoANI) values below species delineation thresholds compared with all described species of the genus Bombella and with each other. TMW 2.2556T and TMW 2.2558T form their own clade within the genus. The major respiratory quinone of all strains was Q-10. The composition of cellular fatty acids was diverse between strains. All strains stained Gram-negative, were rod-shaped, strictly aerobic, pellicle-forming, catalase-positive, oxidase-negative, mesophilic and grew over a wide pH range; they were halosensitive but glucose-tolerant. Unlike the other studied strains, TMW 2.2558T was non-motile. Phylogenetic, chemotaxonomic and physiological analyses revealed a clear distinction between all the strains and species with validly published names. All the data support the proposition of four novel species within the genus Bombella , namely Bombella pluederhausensis sp. nov., Bombella pollinis sp. nov., Bombella saccharophila sp. nov. and Bombella dulcis sp. nov., with the respective type strains Bombella pluederhausensis sp. nov. TMW 2.2543T (= DSM 114872T, = LMG 32791T), Bombella pollinis sp. nov. TMW 2.2556T (= DSM 114874T, = LMG 32792T), Bombella saccharophila sp. nov. TMW 2.2558T (= DSM 114875T, = LMG 32793T) and Bombella dulcis sp. nov. TMW 2.2559T (= DSM 114877T, = LMG 32794T). Moreover, three genomes available in the NCBI database that have not yet been described as species with validly published names could be assigned to the proposed species. Bombella sp. ESL0378 and Bombella sp. ESL0385 to Bombella pollinis sp. nov. and Bombella sp. AS1 to Bombella saccharophila sp. nov.