Effects Of Two Kinds Of Ecdysteroid In Plant On Detoxifying Enzymes Of Harmonia Axyridi

In order to find out the effects of ecdysterone and cyasterone on the activities and gene expression of detoxifying enzymes of the third instar larva of Harmonia axyridi(Pallas)(Coleoptera:Coccinellidae)and find out the safe dose of ecdysteroid in plant.In this article,the RT-PCR and biochemical methods were used to determine the effects of five different concentrations of ecdysterone and cyasterone,which were O.lmg/L?0.5mg/L?1mg/L?5mg/L and 10mg/L,on the activities of carboxylesterase(CarE)?acid phosphatase(ACP)?alkaline phosphatase(ALP)?glutathione S-transferase(GSH-ST)and Cytochrome P450(P450)and CarE mRNA expression of H.axyridi(Pallas)third instar larva treated by spraying those phytoecdysteroids.The results showed that the CarE mRNA expression and CarE activity of the larva treated by ecdysterone under the concentration less than 1mg/L appeared a regular pattern,that was increased first,then returned to and maintained at normal level or decreased slightly,increased again,then returned to the normal level again quickly.When the concentration reached to 5mg/L,CarE mRNA expression and CarE activity did not increased but decreased continously.When the concentration reached to 10mg/L,CarE mRNA expression and CarE activity appared been restrained state at all the observing time;Activity of ACP in the larvae treated by different concentrations ecdysterone maintained been restrained state at all the observing time.When the concentration was less than lmg/L,after treated 48h,activity of ACP returned to the normal level.If the larvae was treated by 5 mg/L or 10mg/L ecdysterone,the inhibition effect increased with the increasing of treated time;Activity of ALP appeared that been actived at the begining,then been restrained,then returned to normal level.When treated by 5mg/L ecdysterone,activity of ALP in those larvae maintained decreased after treated 12 hours.When the concentration reached 10mg/L,activity of ALP maintained been restrained states at all the times been observed;Treated by the concentrations under 5mg/L,activity of GSH-ST were increased.When the concentration reached 10mg/L,activity of GSH-ST maintained been restrained states at all the observing time;When the concentration was under 1mg/L,content of P450 maintained increased after treated 24 hours.When the concentration reached 10mg/L,content of P450 also maintained been restrained states.Treated by five different concentrations of cyasterone,CarE activity of the larva appeared that increased first,then decreased,then back to the nomal level;Except treated by 0.1 mg/L cyasterone,activity of ACP of larvae treated by the other concentrations appeared that smothered first,then back to the nomal level.When treated by 0.1 mg/L,activity of ACP was not significantly difference compared with that of the control group;Activity of ALP appeared that been actived first,then been restrained.When treated by 0.1 mg/L or 0.5mg/L cyasterone,activity of GSH-ST was not significantly affected comparing with that of control group.Treated by 1mg/L or 5mg/L,activity of GSH-ST was actived at the 12thh after treatement and returned to the normal level after treated 24h.Treated by 10mg/L,activity of GSH-ST appeared been actived from 4thh to 12thh and backed to nomal level after treated 24 hours.Treated by five different concentrations cyasterone,the content of P450 appeared been active after treated for more than 24 hours.In conclusion,ecdysterone and cyasterone have significant influence on the activities of detoxifying enzymes of the third instar larva of H.axyridi(Pallas).Cyasterone is conparatively safe in those two phytoecdysteroids.When the phytoecdysteroid is going to be used in the field,the using concentration should be carefully considered.