Expression Of Hsp70 And Hsp90 In Diapause Microplitis Mediator (Hymenoptera: Braconidae)

Microplitis mediator (Hymenoptera: Braconidae) is an endoparasitoid wasp parasitizing noctuid larva. It is an important biological agent to control cotton bollworm (Helicoverpa armigera) in the cotton field by parasitizing rate at 22.9%. The diapause habit of the wasp at its last instar in the cocoon makes it being convenient for commercializing the wasp to control the cotton bollworm. Illustrating molecular regulatory mechanism of diapause of the wasp will not only enrich knowledge of insect diapause, but direct utilization of the wasp to control the cotton bollworm. In the dissertation we set three kinds of temperature and photoperiod regimen to rear armyworm (Pseudelatia separata) larvae, another host, parasitized by the wasp, which will provide suitable materials to analyze regulatory mechanism of the wasp diapause under different temperature and photoperiod. Under the regimen 10h light and 14h dark photoperiod at 17℃, diapause wasp larvae kinking brown cocoons were reared. Under the regimens 24h dark photoperiod at 17℃and 16h light and 14h dark photoperiod at 26℃, nondiapause wasp larvae kinking green cococns were reared. Expression of the heat shock protein genes hsp70 and hsp90 were analyzed in the three treatments.Parts of hsp70 and hsp90 genes were sequenced. The sequenced length of hsp70 is 1022bp whose homology is over 70% compared with other organisms. The 1079bp sequenced length of hsp90 is also over 70% compared with the same organisms. Real-time PCR showed that the two genes expressed in a relative low level whenever they expressed in diapause or nondiapause wasps. There are no significant differences of hsp70 and hsp90 expression between diapause and nondiapause insects.SDS-PAGE analysis showed protein profiles were different between diapause and nondiapause larvae in level of content and kind. Hemolymphs of Pseudaletia separata larvae parasitized by M. mediator under the three regimens were analyzed with IEF (isoelectri focus) technique. The results showed that photoperiod and temperature affected protein profiles of the host hemolymph significantly.