Effect Of Wheat Varieties On Activities And Gene Expression Levels Of Three Detoxification Enzymes In Sitodiplosis Mosellana (Diptera: Cecidomyiidae)

The orange wheat blossom midge,Sitodiplosis mosellana(Gehin),is a key pest of wheat crops in the northern hemisphere.Planting resistant varieties is the most economical and effective way to manage S.mosellana populations.This study aims to explore the effect of content of secondary chemicals in wheat kernels on detoxification enzymes in Sitodiplosis mosellana larvae.Selected eight varieties,were assayed the contents of ferulic acid,tannins,flavonoids and total phenols in wheat kernels of different varieties,and detected the activity and gene expression of glutathione S transferase(GSTs),carboxylesterase(CarE)and cytochrome P450(CYP450s)in Sitodiplosis mosellana larvae feeding different wheat varieties by ELISA and qPCR.The main results in this study were as follows:1.Significant differences were found in the contents of ferulic acid,tannins,flavonoids and total phenols in wheat kernels of different varieties(P < 0.05).The contents of ferulic acid and tannins in resistant variety Kenong 1006 were the highest,significantly higher than four susceptible varieties.The highest content of total phenols was found in resistant variety Jinmai 47 and the lowest in Shannong 33;Xinong 88 had the highest content of flavonoids,while Xiaoyan 6 had the lowest.Our results indicated that ferulic acid in kernels of wheat was closely associated with the resistance of wheat varieties to S.mosellana,and the higher the content of ferulic acid the higher resistance.2.The activities of CarE,GST and CYP450 s in S.mosellana larvae feeding different wheat varieties were significantly different.The activities of CarE,GST in S.mosellana larvae feeding susceptible varieties were lower than those of resistant varieties,outside Xiaoyan 6.The highest activity of CYP450 s was recorded in larvae feeding Xiaoyan 6,the lowest was founded in those feeding Kenong 1006.The correlation analysis showed that the ferulic acid in kernels of wheat was significantly positively correlated with the activities of CarE and GST.The correlation between the contents of tannins and the activities of CYP450 s was significantly negative.3.The impact of different wheat varieties on the expression levels of SmGSTd1?SmGSTd2?SmCarE-1?SmCarE-2 and SmCYP6M1 in S.mosellana larvae was significant.Expression levels of SmGSTd1?SmGSTd2 and SmCarE-2 in S.mosellana larvae feeding resistant varieties were higher than those feeding susceptible varieties.Larvae feeding Shanmai 139 had the highest expression levels of SmCarE-1,while those feeding Xiaoyan 6 had the lowest.Expression levels of SmCYP6M1 were the highest feeding Xinong 88,those feeding Yaoyan 6 had the lowest expression level.4.The correlation analysis showed that the expression levels of SmGSTd1,SmGSTd2 and SmCarE-2 were significantly positively correlated with activities of GSTs and CarE.There were no significant correlation between the expresion level of SmCarE-1,neither SmCYP6M1 and activity of CarE,CYP450 s.