Varroa jacobsoni mites that differ in their reproductive success on the European honey bee (Apis mellifera) display differential gene expression

Varroa mites are considered the biggest health problem that honey bees face worldwide. Varroa jacobsoni is known to only live and reproduce in drone brood of Apis cerana while V. destructor is known to live and successfully reproduce in both A. cerana and A. mellifera. However, we have samples of V. jacobsoni from a small island population found in Papua New Guinea that is highly destructive to A. mellifera, the primary species used for pollination and honey production. Therefore, these recently discovered populations of mites represent an enormous threat to apiculture around the world.

Our lab has sequenced and assembled for the first time a de novo transcriptome of the parasitic mite V. jacobsoni using pools of mites from seven different samples. We also performed a preliminary differential gene expression (DE), analysis of the transcriptomes derived from six of the seven biological replicates of V. jacobsoni populations that differ in their reproductive success on A. mellifera.

Using the edgeR package for the DE analysis we found 1013 differentially expressed genes (FDR < 0.05), between the mites reproducing in A. cerana and the mites reproducing in A. mellifera, of which 93% were up regulated in A. mellifera. We searched for orthologous genes in public databases (Blast/NR, GO and UniProt) and we found that only 698 of the 1013 differentially expressed genes were associated with a functional description, such a biological regulation, metabolic process, molecular binding categories and methyltransferase activity.