Reclassification of seven honey bee symbiont strains as Bombella apis

Authors: SMITH, ERIC - Indiana University; Anderson, Kirk; Corby-Harris, Vanessa; MCFREDERICK, QUINN - University Of California; NEWTON, IRENE - Indiana University

Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2020
Publication Date: 5/8/2020
Citation: Smith, E., Anderson, K.E., Corby-Harris, V.L., Mcfrederick, Q., Newton, I. 2020. Reclassification of seven honey bee symbiont strains as Bombella apis. International Journal of Systematic and Evolutionary Microbiology. https://doi.org/10.1101/2020.05.06.081802.
DOI: https://doi.org/10.1101/2020.05.06.081802

Interpretive Summary: Honey bees are important pollinators of many major crops and add billions of dollars annually to the US economy through their services. Recent declines in the health of the honey bee have startled researchers and lay people alike as honey bees are agriculture’s most important pollinator. One factor that may influence colony health is the microbial community. Although honey bee worker guts have a characteristic community of bee-specific microbes, the honey bee queen digestive tracts are colonized predominantly by a single acetic acid bacterium tentatively named Candidatus Parasaccharibacter apium. This bacterium is related to flower-associated microbes such as Saccharibacter floricola, and initial phylogenetic analyses placed it as sister to these environmental bacteria. We used a combination of phylogenetic and sequence identity methods to better resolve evolutionary relationships among P. apium, strains in the genus Saccharibacter, and strains in the closely related genus Bombella. Interestingly, genetic comparisons and DNA based relationships indicate that many strains labeled as P. apium and Saccharibacter sp. are all the same species as Bombella apis. We propose reclassifying these strains as Bombella apis and outline the data supporting that classification below.

Technical Abstract: Honey bees are important pollinators of many major crops and add billions of dollars annually to the US economy through their services. Recent declines in the health of the honey bee have startled researchers and lay people alike as honey bees are agriculture’s most important pollinator. One factor that may influence colony health is the microbial community. Although honey bee worker guts have a characteristic community of bee-specific microbes, the honey bee queen digestive tracts are colonized predominantly by a single acetic acid bacterium tentatively named Candidatus Parasaccharibacter apium. This bacterium is related to flower-associated microbes such as Saccharibacter floricola, and initial phylogenetic analyses placed it as sister to these environmental bacteria. We used a combination of phylogenetic and sequence identity methods to better resolve evolutionary relationships among P. apium, strains in the genus Saccharibacter and strains in the closely related genus Bombella. Interestingly, measures of genome-wide average nucleotide identity and aligned fraction, coupled with phylogenetic placement, indicate that many strains labeled as P. apium and Saccharibacter sp. are all the same species as Bombella apis. We propose reclassifying these strains as Bombella apis and outline the data supporting that classification below.