Varroa jacobsoni haplotypes 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. Two species of the genus Varroa are known to cause damage to honey bees. Varroa destructor was first described in Apis cerana in Asia more than a decade ago and is known to live and successfully reproduce in A. cerana and in A. mellifera. V. jacobsoni was first described in the Asian honey bee A. cerana and is believed to only live and reproduce in drone brood of A. cerana. 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 for the first time the transcriptome of the parasitic mite V. jacobsoni. Currently, we are analyzing the RNA sequence data of three different pools of V. jacobsoni populations that differ in their reproductive success on A. mellifera. In our preliminary differential gene expression analysis we found significant differences in transcript level between the reproductive mite samples and the non-reproductive one. Blast and Gene Ontology results revealed that some of the largest differences included cuticular proteins, secreted salivary gland and peritrophic membrane chitin binding proteins. A more detailed analysis of the differentially expressed transcripts is under way with the addition of two biological replicates for two of our previous samples of mites, which will account for honey bee hive and geographical variation. In addition, the transcriptome data obtained from this project will also be part of our contribution to the V. jacobsoni genome project lead by the Hunt lab.