Identification And Expression Pattern Of Mosquito Ionotropic Receptors In Its Searching Host Odour

Female mosquitoes after mating need a blood meal to promote the reproductive process.The blood feeding transmits extremely harmful infections including malaria,yellow fever,dengue fever and other arboviruses,which makes the mosquitoes to be one of the most harmful creatures to human health.On the other hand,the super sensitive sense of smell in host searching and locating is always a source of innovation in a biosensor.However,the knowledge of the olfactory mechanism in mosquitoes is not enough to support the deeper and broader demands in mosquito control and olfactory bionic.In the present study,the Ionotropic Receptor?IR?related to olfaction in two mosquito species are explored for the first time,we use the main olfactory organ-antenna as our research target,the expression changes in before and after blood meal as our clue,and mainly focus on the relationship between the newly IR and the traditional Odour Receptor?OR?,in order to speculate the important role in host searching in mosquitoes.Studies on chemosensory biology in female Anopheles sinensis are quite lacking,the current reference genomic datas are imcomplete.In this study,we sequenced mRNA extracted from An.sinensis female antennae pre-and post-blood meal.The bioinformatics was used to optimize 8288 gene structures,and predict 1828 new transcripts,which greatly enriched and improved the gene datas of An.sinensis.The Raw data have been deposited at the Short Read Archive?NCBI?.We analyzed the antenna transcriptome differences of non-blood-fed females and that of blood-fed females,which were verified by qPCR.The expression of OBP,OR,IR and GR,which are known as olfactory related genes in the antenna of An.sinensis,was systematically identified and analyzed.The original gene data of OBP were optimized,the annotation of the other three types of olfactory related genes were supplemented,and the differential expression of metabolism after blood meal were analyzed.This article mainly focuses on the olfactory related gene family IR.According to the conservation relationship of the co-receptors between species,and their association with iGluR?ionotropic Glutamate Receptors?,we identified the co-receptor gene AsinIR8a and AsinIR25a from An.sinensis for the first time.The domain of their amino acid sequence,the specific site and the evolutionary relationship were analyzed.Double-labeled in situ hybridization were used to analyze the distribution between these two chaperone receptors in IR and which in OR.Our research confirmed that the structure and distribution of mosquito IR are independent of OR and exist in the olfactory recognition system of An.sinensis.The sensitivities of the two olfactory sensory proteins are independent of each other,but also mutual cooperation.Aedes albopictus is a world wide mosquito species,the research of IR is,however,quite limited.In this paper,102 possible AalbIR genes were screened and named from the genome of Ae.albopictus,and 19 of them were identified by tissue-specific RT-PCR.The results were compared with the functional characteristics in the known IRs of Drosophila melanogaster,we discussed their evolutionary relationship and differences.Finally,we compared the transcript expression levels of the 19 expressed IR genes in the antenna of blood-fed femaled with that of non-blood-fed females by qRT-PCR.The homology analysis were used to predict that the down-regulated genes could be related to mosquito-recognizing compounds such as amines and carboxylic acids.In this paper,we first proposed that the artificial deficiency of the flagellomeres of mosquito antenna may effect their blood feeding behavior,and designed the behavioral experiments rationally,the idea is different from the previous studies which identified responses of receptors to components,in order to understand the olfaction mechanisms.We confirmed that the 6^th and 7^th flagellomeres on Ae.albopictus antenna are important in the olfactory detection of host searching,analyzed and discussed the sensilla distribution on the each antenna segment,odor molecules sensitivity and so on.