Defensin gene sequences of three different bumblebees, Bombus spp.

We previously reported a defensin gene from the bumblebee Bombus ignitus. Here we report sequences and their expression profile of defensin genes from three other bumblebees, B. terrestris, B. ardens ardens, and B. hypocrita sapporoensis. We compared these defensin gene structures to those previously reported from two other bees, Apis mellifera and B. ignitus, and found that all bee defensin genes contain three exons. Comparative analysis of the deduced amino acid sequences of defensin cDNAs revealed that, except for B. pascuorum, bee defensin genes encode a mature peptide of 52 residues. The transcriptional expression profiles of the defensin gene in the fat body of worker bees in all 3 species revealed that defensin genes were induced by lipopolysaccharide stimulation, indicating an acute transcriptional response to bacterial infection.