Project description:The mite Varroa destructor is currently the greatest threat to apiculture as it is causing a global decrease in honey bee colonies. However, it rarely causes serious damage to its native hosts, the eastern honey bees Apis cerana. To better understand the mechanism of resistance of A. cerana against the V. destructor mite, we profiled the metabolic changes that occur in the honey bee brain during V. destructor infestation. Brain samples were collected from infested and control honey bees and then measured using an untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based global metabolomics method, in which 7918 and 7462 ions in ESI+ and ESI- mode, respectively, were successfully identified. Multivariate statistical analyses were applied, and 64 dysregulated metabolites, including fatty acids, amino acids, carboxylic acid, and phospholipids, amongst others, were identified. Pathway analysis further revealed that linoleic acid metabolism; propanoate metabolism; and glycine, serine, and threonine metabolism were acutely perturbed. The data obtained in this study offer insight into the defense mechanisms of A. cerana against V. destructor mites and provide a better method for understanding the synergistic effects of parasitism on honey bee colonies.
Project description:While Apis cerana cerana, like Apis mellifera, undergoes a behavioral transition from in-hive nursing to outdoor foraging duties, nothing is known about the genes underlying this social signal-triggered aged-related transition in this species. Here, we simultaneously sequenced the head transcriptomes of the 7-day-old normal nurses (N7BY), 18- and 22-day-old normal foragers (N18CJ and N22CJ), 7-day-old precocious foragers (Tq7CJ) and 22-day-old overaged or reverted nurses (Tq22BY) of A. cerana cerana by RNA-seq and made a 3-tier comparison (from pairwise to group-wise and between-group) to unravel the genes associated with this transition. Six pairwise comparisons revealed 165-492 differentially expressed genes between nurses vs. foragers. Subsequent 3 group-wise and 1 between-group comparisons narrowed the transition-associated genes down to 18 nurse- and 41 forager-unique genes and 29 (14 and 15 genes upregulated in nurses and foragers, respectively) differentially expressed genes between the 3 types of foragers and 2 types of nurses. The uniquely expressed genes are usually low-abundance long noncoding RNAs, transcription factors, transcription coactivators, RNA-binding proteins, kinases or phosphatases involved in signaling transduction and/or gene expression regulation, whereas the differentially expressed genes are often high-abundance downstream genes that directly perform the tasks of nurses or foragers, such as major royal jelly proteins for nurses and the genes involved in sugar/protein digestion, lipids/fatty acids metabolism, plant allelochemicals detoxification and defense against pathogens and predators for foragers. Mapping of the clean reads to the published A. mellifera genome uncovered that the 3 types of foragers had a greater percentage of reads from annotated exons and intergenic regions, whereas the 2 types of nurses had a greater percentage of reads from introns. Taken together, these results suggest that the reciprocal nurse-forager behavioral transition of the A. cerana cerana is regulated by a social signal-triggered intron-exon/intergenic epigenetic shift and the resulted transcriptional shift of the nurse- and forager-associated genes.