Gene Expression Analysis Of The Hypopharyngeal Gland Between Apis Mellifera And Apis Cerana Workers

Royal jelly is secreted by hypopharyngeal gland(HG) and mandibular gland which locate in the head of worker honeybees about 6~12 days-old. Royal jelly has the very complicated composition and many important functions. Researches showed that the yield of royal jelly between Apis mellifera and Apis cerana has a huge difference, which mainly because of the development degree of HG and their secretory activity of royal jelly.In this study, we analyzed the mRNAs expression difference of the different developmental stages of HGs(newly emerged worker, nurse and forager) between Apis mellifera ligustica(Aml) and Apis cerana cerana(Acc) using digital gene expression profiling technology(DGE) which belongs to Solexa platform. Besides that, we also analyzed the expression of SV2 C, PDK1, eIF-4E, e IF-4E, cell growth-regulating nucleolar protein, IMP and TGF-βR1 in different developmental stages of HG(nurse, forager and reversed nurse) in Aml using quantitative real-time PCR(q-PCR).For DGE, 3564493, 3551143 and 4811364 clean tags were detected from Aml newly emerged worker, nurse and forager stages HGs respectively. A total of 1482 genes showed an expression difference in at least one pairwise comparison. Of these, 279, 614 and 1419 genes were differentially expressed in the comparisons among newly emerged worker vs. nurse, nurse vs. forager, and newly emerged worker vs. forager. And corresponding to that, there were 2441553, 2421403 and 2709506 clean tags detected from Acc newly emerged worker, nurse and forager stages HGs respectively. The DEGs number was 1209, 103 and 331 respectively, a total of 1313. Most of these DEGs’ expression in Aml and Acc reduced continually with the increase of time. In addition, their were 623, 1072 and 462 DEGs between Aml and Acc newly emerged worker, nurse and forager stages HGs respectively, a total of 1417. With 509, 981 and 182 genes up-regulated and 114, 91 and 280 genes down-regulated in Aml groups. These results suggested that mRNAs probably played an important role in regulating the development of HGs and the process of royal jelly secretion. In a result, we screened out 1 gene which perhaps affected the secretory activity of royal jelly in HGs and 5 genes maybe associated with the development of HGs.Thereafter we analyzed above-mentioned 6 genes in Aml nurse, forager and reversed nurse stages HGs by means of q-PCR. Results indicated that SV2 C could be regarded as candidate gene associated with the secretory activity of royal jelly in HGs, e IF-4E, TGF-β, cell growth-regulating nucleolar protein and IMP perhaps associated with the development of HGs, and PDK1 might be related with the lifespan of HGs.