Identification And Expression Profiling Of Odorant-binding Proteins In Bactrocera Dorsalis

Bactrocera dorsalis is important quarantine pests in the world, due to this pestbeing serious damage to fruit and vegetable industry. The main methods in pestcontrol for B. dorsalis are chemic control, sexual attractants, manual-packingprotection at home and abroad. However, the above control strategies have manydefects, and be ineffective. Therefore, it will be necessary to develop the novelcompounds interfere with insect behavior by molecular biology techniques. Studieshave reported that insect odorant-binding proteins as molecular targets, and provide todrug design using the protein structure, thereby to develop the novel efficientchemicals. It foreshows the develop direction of the future method for pest control.To identify the odorant-binding proteins genes, based on antennal transcriptomewe have established, both bioinformatic methods were employed to obtain thefull-length of15OBPs. Bioinformatic methods also were employed to analyze thecharacteristic of insect OBPs, and the phylogenic analysis with other flies. Our resultsshow that all BdorOBPs we identified are in accordance with conserved features ofOBPs, only conservative cysteine sites of Cont₆4, Cont₈3, Cont₁03, Cont₁13and Cont₁26b are a slight deviation. And Cont₄, Cont₇5, Cont₈9, Cont₁13arewithout signal peptide amino acids. The result of phylogenetic analysis showed that1)Cont₄, Cont₇5, Cont₈6, Cont₁15, Cont₁26b and Cont₁28with GOBPs of C.capitata clade the same limb of the evolutionary tree.2) Cont₈0, Cont₈3, Cont₈9,Cont₁03and Cont₁29with PBPs of other fruit flies clade the same limb.3) Cont₅,Cont₆4, Cont₈8, Cont₁13with entirety OBPs of Drosophila melanogaster, C.capitata other fruit flies clade the same limb respectively.To investigate BdorOBPs expression in different adult stage, Double-standardCurves method of relative quantification PCR were employed to detect expressionpattern of BdorOBP61. The result showed that the expression of BdorOBP61wasdetected in the whole adult. BdorOBP61expression of male and female in the firstday after eclosion were highest, and it were decreasing in a few days afterwards.During1-20day after eclosion, female expression were higher than male, and the expression peak was appeared in17day. Besides that, BdorOBP61expression in maleand female was little difference.In order to examine further the potential functions of BdorOBPs binding the sexpheromone or oviposition attractants, the relative quantification method-2－ΔΔCTwereemployed to detect tissue-differential expression of15BdorOBPs both in male andfemale. The result showed that1) Cont₄, Cont₅, Cont₆4, Cont₈0, Cont₈3,Cont₈6, Cont₈9, Cont₁13, Cont₁16, Cont₁26b, Cont₁28and Cont₁29hadhigher transcription levels in antennae. Of the12OBP genes, two （Cont₆4andCont₈6） in male had significantly higher than famle.2) Cont₅, Cont₈0, Cont₈3,Cont₈9, Cont₁13, Cont₁26b, Cont₁28and Cont₁29antennae transcriptionlevels in female had significantly higher than male.3) Cont₆4, Cont₈3, Cont₁13,Cont₁15and Cont₁29belong to antennae-higher transcription;4) Cont₇5,Cont₈8and Cont₁03had higher transcription levels in head, and Cont₇5belonghead-specific.