Proteomic Analysis Of Honeybee (Apis Mellifera L.) Caste Differentiation Between Worker And Queens Larvae

The honeybee (Apis mellifera L.) is a eusocial insect that has typical of the caste differentiation. In the colony, the queen and worker are both female, but only the queen bee has reproductive capacity. Comparison of the proteome differece between the two castes will help understanding molecular mechanism of honeybee caste differentiation.The results showed that 288 and 274 proteins were detected in the proteome profile of queen larvas on day 3 and day 5, respectively, and worker expressed 259 and 236 proteins on day 3 and 5 old larvae, respectively. Also, in the head of 11-day pupaes, evidently higher number of total proteins (311) was detected in queen than those of worker (278). On the third day,156 proteins were detected in both queen and worker larvaes, while 132 proteins were specific to queen larvae, and 103 proteins were exclusive to workers larvae. While on the fifths day, larvaes of queen and worker had 95 shared proteins,179 and 141 proteins were specific to queen larvaes and worker larvaes, respectively. At the eleventh day,194 proteins were detected commonly in the head of queen and workers, while 117 and 84 proteins were unique to the heads of queen and worker, respectively. Significant differences had been found in the proteome between queen and worker during the process of caste differentiation. While the increased number of total and specific proteins in queens is likely that the metabolic rate of queens is higher than that of workers. The proteins both in queen and worker suggest that they should be indispensable for development, but their expression patterns are different between the two bee castes. A mass of proteins differently expressed at each time-point indicate that different caste developmental stages need different proteins to be involved in.60 proteins which differentially expressed between the worker and queen larvae on day 3 and 5 were successfully identified by MALDI-TOF and categorized into 8 functional groups,i.e. carbohydrate metabolism and energy production(35%), Amino acid and fat acid metabolism(17%), Antioxidant system(15%), Development(12%), Protein folding(10%), Transcription/translate(6%), Nutrition Storage(4%) and Unknown(1%). The largest group of the identified proteins was carbohydrate metabolism and energy production, indicating that the developments both of the two castes need a lot of energy for the larval developemnt. Differentially expressed proteins between the worker and the queen larvae were clustered, and finding that queen larvae up-regulate more proteins related to carbohydrate metabolism and energy production than worker larvae indicating energy requiment is probably a driving force for the lava becoming a queen.When placed the 60 identified proteins that differentially expressed between the worker and the queen larvae on day 3 and 5 into biology network,24 key node proteins were detected, including, aldehyde dehydrogenase, aldehyde reductase, ATP synthase beta subunit, bellwether, enolase, phosphoglycerate mutase, transketolase, 14-3-3 protein epsilon, actin-87E isoform 2, cathepsin D, imaginal disc growth factor 4, lethal(2)37, arginine kinase, fatty acid binding protein, proteasome subunit alpha type 5, peroxiredoxin 2540, glutathione S transferase S1, thioredoxin peroxidase 1, heat shock protein cognate 3, ERp60, larval serum protein 2, Translational controlled tumor protein.These proteins not only are indispensable in caste differentiation of bee, but also help to provide target proteins for further verification of the caste differentiation.