| Honey bees have evolved an intricate system of chemical communication to regulate their multifaceted social interactions. To gain better understanding how the drone and the worker react to different olfactory responses and undertake their activities, morphology and differential proteomics research were carried out. The antennae of drones and workers from Apis mellifera ligustica and A. cerana cerana were examined using scanning electron microscope (SEM), and the antennae proteins were extracted, then two dimensional electrophoresis (2-DE), mass spectrometry, quantitative real-time PCR (qRT-PCR) and bioinformatics approaches were used.Morphological assay by SEM showed that the antennae of drone are lager than worker', and the total poreplate sensilla showed significant higher number in the drone than those of the worker (almost 7.5 times in A. mellifera ligustica, almost 3 times in A. cerana cerana), suggested to assist its high antennal olfactory functions, particularly the sex pheromone related responses. In contrast, the number of hair-like sensilla of workers was two-fold higher than drones', This is likely to help the foragers to search nectar resource quickly, to sense temperature, humidity and mechanical force.With the comparison of the proteins profile of sexual matured drones and foragers' antennae (A. mellifera ligustica), a total of 484 and 439 protein spots were detected in adult drones and workers'antennae, respectively, of which 416 expressed proteins were shared between drone and worker antennae, it means that they evolve conservatively between them.61 proteins differentially expressed proteins were identified, of which 41 proteins (67%) were highly regulated in the sexual mature drones' antennae whereas only 20 proteins (33%) upregulated in forager worker bees'. Proteins associated with fatty acid metabolism, antioxidant activities and protein folding were highly upregulated in the sexual mature drones' antennae indicating their significance to detection and degradation of sex pheromones required in queen mating. The forager worker bees' antennae highly expressed proteins related to carbohydrate and energy metabolism and the molecular transporters signifying high demand for metabolic energy and odorant binding proteins in their foraging activities and other olfactory responses. Some proteins were found in the results of functional enrichment and biological interaction networks (BIN) analysis. The involvement of carbohydrate and energy metabolism, fatty acid metabolism, cytoskeleton, antioxidant and molecular transporters in these groups reveals their important role in the antennal olfasctory function. Over 80% of the functional enrichment analysis and 45% of the BIN of the altered antennal proteins were covered by carbohydrate metabolism and energy production and molecular transporters, respectively confirming that these two protein families play the crucial role in the antennal olfactory function of sexual mature drone and forager worker bees.10 key node proteins in the BIN were validated at the transcript level and 9 proteins displayed comparable expression with the qRT-PCR analysis, and these proteins provide us some target proteins for further genetically manipulation.By comparison of the proteins profile of sexual matured drones and foragers' antennae (A. cerana cerana),424 and 408 protein spots were detected in drones and workers' antennae, respectively, and 416 shared proteins mean that they evolve conservatively between them.46 differentially expressed proteins were identified, proteins were highly regulated in the sexual mature drones' antennae, which was involving in carbohydrate and energy metabolism, fatty acid metabolism, development and molecular transporters, and they provide energy and molecular transporter in recognizing and processing of pheromone. More proteins expressed highly in workers, which related to carbohydrate and energy metabolism and the molecular transporters, this demonstrates that foraging activities, defense, and other olfactory responses need high metabolic energy and more odorant binding proteins. Although Apis mellifera ligustica and Apis cerana cerana belong to two different species, the kind and expressional level of differentially expressed proteins seem similar between drones and workers'antennae and it indicates molecular mechanism is conservative at a certain extent in different species. For Apis mellifera ligustica, more proteins expressed highly in drone and worker respectively, which related to carbohydrate and energy metabolism and antioxidant. However the results were contrast in Apis cerana cerana, the dispency between two spiecies may contribute to different evolve level. This differential proteomic analysis reveals sex-biased protein expression in the sexual mature antennae of drone and forager worker bees, and indicates their responding mechanism to different olfactory functions accordingly. Moreover, the results will open the way for future detailed functional analysis in the antennae of the two honeybee casts. |
