Identification And Expression Profile Analysis Of Chemosensory Genes In Phyllotreta Striolata( Fabricius)

Phyllotreta striolata（Fabricius）is one of the major pest of cruciferae vegetable, which cause serious damage to the cruciferae vegetable production in south of China. The pest control strategy of P. striolata rely principally on chemical control, but overuse of pesticides cause insecticide resistance and food security hidden danger. Therefore, we need to develop novel control strategy for this pest. The application of attractants and repellents would be the future direction of development of pest control technicians. In addition, the understanding of chemoreception on molecular level is limited. The study of chemosensory gene would be essential to expanding understanding this field, and provides scientific information for functional characterization.Based on previous transcriptome data of P. striolata in our laboratory, the chemosensory genes of P. striolata were identified using BLAST search, RACE and bioinformatics.The characteristics of chemosensory gene were also defined and phylogenic analysis of P. striolata chemosensory gene was carried out. The q TR-PCR technology was employed to investigate the differential expression genes between olfactory tissue and non-olfactory tissue in P. striolata. Through the research, the following results were obtained: 1) Identification and bioinformatics of P. striolata chemosensory geneBy means of the bioinformatics methods and RACE, we identified three odorant-binding proteins, two chemosensory proteins, one odorant receptors, seven Ionotropic receptors, two sensory neuron membrane proteins, one gustatory receptors.Then we constructed the evolution tree with selected chemosensory genes of other insects. The phylogenetic analysis indicated that the evolutionary relationships of P. striolata chemosensory genes were closed with Coleoptera insect such as Tribolium castaneum.（1）Pstr OBP1, Pstr OBP2 and Pstr OBP3 share the highest homology with Monochamus alternatus Malt OBP4、Malt OBP3 and Tribolium castaneum Tcas OBP19 d, the homologys are 52%、41% and 42% respectively.（2）Pstr CSP1 and Pstr CSP2 show the highest homology with Tenebrio molitor Tmol CSP3 and T. castaneum Tcas CSP6, the homologys are 57% and 37%.（3）Pstr SNMP1 and Pstr SNMP2 share the highest homology with Dendroctonus ponderosae Dpon SNMP（AFI45066.1） and T.castaneum Tcas SNMP2-like（XP₀08198962.1）, the homologys are 49% and 46% respectively.（4）Pstr IR1, Pstr IR2, Pstr IR5, Pstr IR6 and Pstr IR7 are all homologous with glutamate receptor ionotropic, kainite, Pstr IR3 and Pstr IR4 share the highest homology with T.castaneum glutamate receptor 2 and T.castaneum glutamate [NMDA] receptor subunit 1, the homologys are 59% and 87%. Phylogenetic tree show that Pstr IR1, Pstr IR2, Pstr IR5, Pstr IR6 and Pstr IR7 claded with Tcas Glu RK1, Pstr IR3 claded with Tcas IR75, Pstr IR4 claded with Tcas|XP₉69654.1.（5）Pstr OR2 shares the highest homology with T.castaneum Tcas OR37,the homology is 34%.（6）Pstr GR1 shows the highest homology with Tcas GR10, the homology is 69%, and they were both homologous with Drosophila melanogaster Dmel GR21 a.2) The expression analysis between olfactory tissue and non-olfactory tissueq RT-PCR technology was employed to investigate the differential expression of Pstr OBP1, Pstr OBP2, Pstr OBP3, Pstr CSP1, Pstr IR1, Pstr IR2, Pstr IR3, Pstr SNMP1 and Pstr SNMP2 between antennae and abdomen apiculus in P. striolata. The results showed that 1) Pstr OBP1 and Pstr OBP2 are predominantly expressed in antennae, and the expression level of Pstr OBP1 in male antennae is higher than female, the expression levels of Pstr OBP2 in male and female antennae are approximate. The expression level of Pstr OBP3 in male abdomens is the highest, and the difference between that in male antennae and female is not significant. We hypothesize that Pstr OBP1 respond to female sex pheromone, Pstr OBP2 respond to ordinary odors, and Pstr OBP3 might assist releasing of aggregation pheromone into the environment, and it also might respond to the aggregation pheromone. 2) Pstr CSP1 expresses both in antennae and abdomens, the expression level of female abdomen is the lowest and the expression levels in other tissues are approximate. 3) Pstr IR1, Pstr IR2 and Pstr IR3 all express in antennae and abdomens, and the expression level of male are higher than female. 4) Pstr SNMP1 and Pstr SNMP2 both express in antennae and abdomens, and the the difference between antennae and abdomens is not significant.