Temporal And Spatial Differential Expression Analysis Of Four Odorant Receptor Genes From Apis Cerana Cerana

In order to adapt the changing environment, insects have evolved into complex and sensitive olfactory system, through which they can perceive external changes so that they obtain information, avoide disadvantages and maintain their individual development and thriving population. Futher studies on the molecular mechanism of insects olfactory will lead to better understand the occurring mechanism of insects olfactory and the co-evolutionary relationship between insects and host plants. Apis cerana cerana is a subspecies of Apis cerana, and a particular native bee species in China. It plays a very important role in the maintenance of ecosystem stability, biodiversity and vegetation specificity. However, their living environment was destroyed due to the introduction of a large number of Apis mellifera, abuse of pesticides and environmental damage, which led to more than 80 percent decrease in their population. Therefore, the protection of A. c. cerana has became urgently. As an experimental animal, we studied the structures of the A. c. cerana odorant receptor gene AcerOr28, AcerOr96, AcerOr35 and AcerOr113 and their expression profiles in different tissues on different developmental stages, the results of studies were as follows:(1) The full length of CDS of AcerOr28, AcerOr35, AcerOr96 and AcerOr113 were 1218, 1239,1206 and 1035 bp and encoding 405,413,402 and 344 amino acids respectively. [GeneBank accession numbers were KT454837.1, KX371646, KX371647 and KT252877.1](2) Various numbers of potential glycosylation and phosphorylation sites were predicted but no signal peptides. Besides, AcerOr35 had seven transmembrane domains, but only six transmembrane domains were predicted in AcerOr28, AcerOr96 and AcerOr113, which was one of the typical structural characters of odorant receptor.(3) Real-time PCR technique was used to study the ontogenetic mRNA expression of AcerOr28, AcerOr35, AcerOr96 and AcerOr113 genes. The results showed that all of the genes were expressed in different tissues on different developmental stages and the expression of antennae was significant higher than the other tissues. In addition, the expressions of AcerOr35, AcerOr96 and AcerOr113 in periods with ample nectar and pollen were less than that in periods with lack of nectar and pollen, but the results was opposite in AcerOr28. In either case, the time of highest expression of AcerOr28 was different from the other genes. And, AcerOr28 was likely considered as a pseudogene due to the high similarity to the pseudogene AmelOr28p, but the definitive conclusion still need to be further studied.