Effects Of PKG On Migratory Characteristics Of Mythimna Separata(Walker)

Mythimna separata(Walker)belongs to Insecta,Lepidoptera,Noctuidae,which is a typical seasonal migratory pest in China.Previous studies have shown that the density of larvae of M.separata affected the migratory behavior of adults,and the adults with high density have tendency to migrate.It has been reported that the PKG gene affected the foraging behavior of insects.Therefore,this paper determined the effect of PKG on the migratory characteristics of M.separata using the candidate gene method,and aims to provide the basic data for clarifying the molecular mechanism of the migratory behavior of M.separata.In this experiment,6 feeding densities(1 larvae/jar,5 larvae/jar,10 larvae/jar,15 larvae/jar,20 larvae/jar,30 larvae/jar)were set up for larvae,and the mRNA expression of PKG gene of the fifth instar larvae in 6 rearing densities was detected by RT-qPCR technique.The results showed that PKG gene expression in the larvae head was different at different densities,and the expression level of PKG in 1 larvae/jar was significantly higher than that of 10 larvae/jar(P<0.05).PKG gene mRNA expression level in the two life-types adult head(1 larvae/jar and 10 larvae/jar)was also different.The expression of PKG in 10 larvae/jar was significantly higher than that of 1 larvae/jar(P<0.05).In addition,the activity of PKG protein in two lifetype adults head was examined by UV spectrophotometry.The results showed that the activity of PKG protein of adult in 10 larvae/jar was higher than that in 1 larvae/jar,but the difference was not significant.The distribution position of PKG in adult brain was detected by the method of immunohistochemistry.The results showed that PKG was positive in the nerve lamina of the optic lobe and the vision cells of compound eye.The PKG protein of the larvae(10 larvae/jar)was activated by pharmacological means.The PKG protein agonist(8-Br-cGMP)was fed to the larvae,and the PKG activity,flight ability and the amount of energy substances of the adult were determined.The results showed that the activity of PKG protein of adults was increased when larvae were fed in 8-BrcGMP,but the increase not significant,which indicated that the activation of PKG protein in larval stage had no significant effect on the PKG protein of adult.From the flight ability,the cGMP-activated treatment group showed a decreasing trend compared with the control group.From the glycogen value,the treatment group showed an increasing trend,and from the glyceride content,the treatment group showed a decreasing trend compared with the control group,but the difference was not significant.It was shown that PKG protein activity was altered during larval stage had no significant effect on flight ability and the amount of energy substances of adults.But the PKG activity of adult is treats whether the migratory ability of the adult has a significant impact or not,it need to be further study.