Physiological Mechanisms Of Interaction Among Barley Yellow Dwarf Virus,Wheat Aphid And Wheat

In order to explore the physiological mechanism of interactions between virus,wheat aphids and wheat,we analyzed the the protective enzymes such as peroxidase POD,catalase CAT,superoxide dismutase SOD,and acid phosphatase ACP,alkaline phosphatase AKP,acetylcholinesterase AchE and other detoxification enzymes activity changes of three aphids(Schizaphis graminum,Sitobion avenae,and Rhopalosiphum padi)and wheat leaves.According to the change of enzyme activity,the genes of SOD and AchE were selected to determine the gene expression level.This study will lay a foundation for exploring the mechanism of insect-virus-plant interaction,and at the same time provide a theoretical basis for the cause of the popular of wheat yellow dwarf and population dynamics of wheat aphid.The following results were obtained in this study: 1.The results of wheat leaf enzyme activity study showed that when BYDV and S.graminum were used together to treat wheat,the late aphid feeding stage would lead to a decrease in CAT activity in wheat,and the previous feeding stage would lead to increasing of ACP activity,BYDV infection increased CAT and AKP activity significantly;when BYDV and S.avenae were treated together,the previous/late feeding stage and BYDV could all significantly affect wheat POD activity.Previous feeding resulted in a significant increase in CAT,SOD,and ACP activity,and late feeding together with BYDV counteracted this effect.BYDV infection caused a significant increase in AKP activity.When BYDV and Rhopalosiphum padi were used together to treat wheat,previous stage feeding resulted in a significant decrease in POD activity,and aphid feeding together with BYDV infection resulted in an increase in CAT activity.The late stage feeding will increase SOD and ACP activity significantly,and BYDV infection will offset this effect.Late stage feeding resulted in decreasing of AKP activity,while BYDV significantly increased AKP activity.The results of the three wheat apid enzyme activities showed that the BYDV-infected wheat resulted in a significant decrease in POD,SOD,CAT,AKP,and AchE activity when BYDV and S.graminum were co-treated.The combination of BYDV and predose feeding resulted in a decrease in POD and AchE activity.Both BYDV and pre-feeding resulted in a decrease in CAT activity,and the decline in AKP activity was caused by pre-feeding,while BYDV alone resulted in a decrease in SOD activity.When BYDV was co-treated with S.avenae,the activities of POD,SOD,ACP and AKP in BYDV infected wheat increased significantly.The activities of POD and SOD were mainly caused by pre-feeding,while BYDV reduced this effect.Both prefeeding and BYDV increased ACP activity.The increase in AKP activity was caused by the combination of pre-feeding and BYDV infection.When BYDV was co-treated with the S.avenae,the activities of SOD,AKP,and AchE were decreased significantly and the AKP activity was significantly increased in the Rhopalosiphum padi.The combination of pre-feeding and BYDV infection led to a decrease in AKP and AchE activity,while only BYDV decreased the activity of SOD.Both pre-feeding and BYDV infection lead to increased AKP activity.The relative expressions of SOD and AchE genes in wheat aphids were consistent with their corresponding enzyme activities.The above results indicate that wheat can adapt to the coinfection of aphids and viruses by changing the enzymatic activity in vivo,and wheat aphids may adapt to the feeding of plant viruses and pre-stage aphids by changing protective enzymes or detoxifying enzymes in vivo.