Cloning, Identification And Analysis Of Odorant Binding Proteins In Aedes Albopictus

The Asian tiger mosquito, Aedes albopictus Skuse as a major species in urban and rural areas in south China is one of the main vector species and contributed to the spread of dengue and dengue hemorrhagic fever in mainland China. So far, there are no vaccines or drugs available for dengue fever. The vector control still plays a major role for prevention and control of this illness. Current strategies for Ae. albopictus urgent control mainly rely on the insecticides spray. Unfortunately, extensive use of insecticides for mosquito control has led to a widespread increasing resistance. It is essential to searching of the effective, safety, environmental friendly methods and techniques based on physiological behaviors for control of adult mosquitoes in sustainable vector management.Mosquito olfaction related to host seeking and feeding behavior. One of the first classes of olfactory proteins molecularly identified in mosquitoes and other insects are odorant-binding proteins (OBPs). They are hypothesized to act either as odorant carriers to facilitate solubilization, thereby raising the effective concentration of hydrophobic odorants.The studies of OBPs mostly focus on Anopheles gambiae, only three OBP genes of Ae. albopictus had been cloned, so far it is not clear about which OBPs are related to the habit of blood feeding and are connected with repeated blood-feeding of Ae. albopictus. As OBPs involve in the first step of molecular recognition, it is necessary to identify OBP genes, study the function and understand the molecular mechanisms underlying the mosquito olfactory system is critical to developing new control strategies. Results of this study as follows:1. A cDNA library was constructed from antennae of 200 adult female Ae. albopictus. Sequencing clones identified two members (AealOBP1 and AealOBP2) of the OBP family. The BLAST search indicated the closest match as the Ae. aegypti odorant-binding protein 56a and 56e partial mRNA with more than 80% homology. Moreover, two olfactory receptors, one odorant receptor, one gustatory receptor and three steroid hormone receptors which are all most homology with the Ae. Aegypti were found.2. Sequences of six members in the OBP family were identified by using degenerate primers, One is same as the AealOBP1. The others (AealOBP3 to AealOBP7) are more than 75% homology compared with the Ae. aegypti, Culex quinquefasciatus and An. gambiae OBP, respectively.3. Expression of the ten OBP genes was investigated by quantitative real-time PCR in the head of adult male and blooded and no-blooded adult female. Expression of AealOBP1, AealOBP4 and AealOBP5 had no difference in the head of blooded, no-blooded adult female and adult male; Expression of AealOBP6, AealOBP46 and AealOBP68 were significantly greater in the head of blooded adult female than no-blooded adult female, but the results of AealOBP3 and AealOBP7 showed a reverse trend; Expression of AealOBP67 and AealOBP46 were significantly greater in the head of adult male than no-blooded adult female; To the contrary, expression of AealOBP7 were significantly greater in the head of no-blooded adult female .