High-throughput sequencing identification of genes involved with Varroa destructor resistance in the eastern honeybee, Apis cerana.

Varroa destructor is the greatest threat to the honeybee Apis mellifera worldwide, while it rarely causes serious harm to its native host, the Eastern honeybee Apis cerana. The genetic mechanisms underlying the resistance of A. cerana to Varroa remain unclear. Thus, understanding the molecular mechanism of resistance to Varroa may provide useful insights for reducing this disease in other organisms. In this study, the transcriptomes of two A. cerana colonies were sequenced using the Illumina Solexa sequencing method. One colony was highly affected by mites, whereas the other colony displayed strong resistance to V. destructor. We determined differences in gene expression in the two colonies after challenging the colonies with V. destructor. After de novo transcriptome assembly, we obtained 91,172 unigenes for A. cerana and found that 288 differentially expressed genes varied by more than 15-fold. A total of 277 unigenes were present at higher levels in the non-affected colony. Genes involved in resistance to Varroa included unigenes related to skeletal muscle movement, olfactory sensitivity, and transcription factors. This suggests that hygienic behavior and grooming behavior may play important roles in the resistance to Varroa.