Occurence Dynamic Of Carposina Sasakii In Apple Cultivating Area Of Yan'an And Its Olfactory Recognition Mechanisms

The Carposina sasakii Matsumura is a widely distributed fruit pest,which mainly damages the fruit trees of Rosaceae and Rhamnacea.The large-scale occurrence of C.sasakii severely limits the sustainable development of fruit industry in China.In order to avoid the adverse effects caused by chemical insecticides on the environment,the development of new-type botanical attractants is the most effective means.At present.the fluctuation of this pest in Hezhuangping town of Baota district,Yangquan Town of Fuxian county,Xiasiwan town of Ganquan county,and Yanhewan town of Ansai county were investigated with the help of sex lure.Using the second generations sequencing technology and bioinformatics analyses,a large number of olfactory related genes were identified in the antennae.The recombinant Csas GOBP2,Csas OBP14,Csas OBP15 and Csas CSP5 were prokaryotically expressed,and the host plant volatiles were screened that strongly bounded to the above recombinant proteins by fluorescence competitive combination tests.The expression patterns of Csas GOBP2,Csas OBP14 and Csas OBP15 in different tissues were detected by real-time fluorescence quantifications,and the physiological functions of these three olfactory proteins were speculated.The main experimental results are as follows:(1)The trapping experiment from April to October in 2018,showed that at least two generations occurred within this period,and whether the third generation occurred is still uncertain.The overwintering individuals extremely synchronously emerged since late May.There are two peaks of trapping in the whole year,from the late June to the Early July,and from the early to the middle August,with the peak number of 38.18 and 31.04 moths per sticky trapper respectively.A total of 8261 C.sasakii were trapped,with an average of 172.4 trapper.The rate of bored fruit was controlled 14.5% and 22.9%,and the control effect effeciency was between 66.2% and 83.8%.(2)Csas GOBP2,Csas OBP14 and Csas OBP15 were expressed in all tissues.Except that Csas GOBP2 expressed higher in the abdomen higher than the antenna,Csas OBP14 and Csas OBP15 in the antenna expressed significantly higher than other tissues(P < 0.05),implying an important role of these genes in the antenna of the C.sasakii.Csas GOBP2 in the abdomen was higher than that in the antennae,suggesting that it may be involved in the olfactory recognition and OBPs transport of insects.Csas GOBP2 expressed about 78.9-folds higher in the antennae of females than males(P < 0.05),Csas GOBP2 is also highly expressed in the abdomen of females,higher than that of both sexes.In addition,Csas GOBP2 was also highly expressed rich in the thorax and wings,and slightly expressed in the head.Csas OBP14 and Csas OBP15 expressed 16 times higher in the antennae of the males than females.(3)A total of 118 olfactory related genes were identified in the antennae of the C.sasakii,including 26 OBPs,16 CSPs,46 ORs,28 IRs and two SNMPs.The prokaryotic expression systems of Csas GOBP2,OBP14,OBP15 and CSP5 were successfully constructed and the active recombinant proteins were purified.r Csas CSP5 was expressed in the supernatant.The fluorescence binding competition experiments revealed that r Csas GOBP2 had strong binding activities to N-dodecyl alcohol(Ki= 3.82 ?M),and to Neroli tertiary alcohol(Ki= 3.30 ?M)(Ki< 20 ?M).r Csas OBP14 had the strongest binding affinity to Pear ester(Ki= 2.65 ?M),while had weak binding affinities towards other substances.r Csas OBP15 had a wide binding spectrum,it had a strong affinity with the main sex pheromones of C.sasakii(Ki= 5.07 ?M).r Csas OBP15 also stongly bounded to 1-Decanol(Ki= 9.11 ?M),Dodecyl alcohol(Ki= 5.46 ?M),Neroli tertiary alcohol(Ki= 1.53 ?M),Decyl aldehyde(Ki= 8.04 ?M),and Pear ester(Ki= 4.86 ?M)(Ki< 20 ?M).Six odor substances were screened in this study: Pear ester,Dodecyl alcohol,1-Decanol,Neroli tertiary alcohol,Decyl aldehyde,and Dodecyl aldehyde.