Effects Of Different Plants Feedings And Starvation On The Digestive Enzyme Activities In Agasicles Hygrophila

Agasicles hygrophila Selman&Vogt is a special natural enemy of Alternanthera philoxeroides(Mart.)Griseb,and scholars at china and abroad have done a lot of research on the Agasicles hygrophila.The molecular mechanism is rarely reported,which undoubtedly affects the process of synergetic evolution between the flee bettle and its host plants.The digestive enzymes in the body of insects including lipase,protease,amylase and cellulase,digestive enzyme activity determines the level of insects on the digestion and absorption of nutrients.In this paper,the digestive enzymes of the plants were studied after 12,24,48 and 96 h of starvation and fed on Alternanthera philoxeroides,Alternanthera sessilis,Beta vulgaris and Beta vulgaris var.cicla.We used biochemical methods to analyze the differences of nutrient,secondary metabolites and water content of four plants,and analyzed the changes of digestive enzyme activity Using the transcriptome database and the database of digital expression profiles,the differentially expressed digestive enzyme genes were screened,clustered and analyzed by RT-qPCR method.Furthermore,the expression of differentially expressed genes was detected by RT-qPCR method.The relationship between digestive enzyme gene and different plants was discussed from the molecular level,which provided the theoretical basis for clarifying the specificity of the parasite.The main findings are as follows:The biochemical analysis of four kinds of plants showed that the content of soluble sugar was from high to low:B.vulgaris>A.sessilis>A.philoxeroides>B.vulgaris var.cicla,protein and tannin content from high to low were:B.vulgaris var.cicla>A.sessilis>A.philoxeroides>B.vulgaris.There were significant differences in the water content of the four host plants between 84.59%-93.98%.B.vulgaris var.cicla has the highest water content,and the water content of A.philoxeroides was the lowest.The digestive enzyme activity assay showed that,the activity of protease activity was the highest at 64.95 ?g·mg-1·min-1 after 24 h starvation treatment,and the activity of fed on A.sessilis protease was the higher after 48 h treatment,and the activity of protease was 125.29 ?g·mg-1·min-1 after treatment for fed on B.vulgaris var.cicla 96 h;and the activity of amylase was the highest at 12,24 and 48 h after starvation,which was 18.36,23.53,23.48 U/mg separately,followed by the higher amylase activity of fed on B.vulgaris,which was 16.78,20.28,22.46,16.91 U/mg respectively,and there were significant differences among these treatments.The cellulase activity of fed on B.vulgaris and B.vulgaris var.cicla was higher than that of A.philoxeroides and A.sessilis at 24?48 and 96 h,and fed on A.sessilis was the lowest after 12?24?48?96 h.The result of phylogenetic analysis of digestive enzyme genes showed that 221 genes related to digestion were screened,including amylase??-glucosidase??-galactosidase??-glucosidase?trypsin?lipase genes respectively.The expression of RPS13,RPL32 and RPS20 were screened out by geNorm and NormFinder software.The optimal expression of RPS13,RPL32 and RPS20 were screened out by using 10 candidate internal reference genes in different plants and starvation conditions.The differentially digestive enzyme expressed genes of A.hygrophila were analysis by RT-qPCR method.(1)After treatment for 48 h fed on A.sessilis,Tryl was the highest,control of 4.67 times.(2)After treatment for 96 h,the Am2 of fed on A.sessilis was the highest,which was 9.19 times of that of the control.(3)After treatment for fed on A.sessilis 48 h,the expression of ?-Amyl was significantly increased 2.71 fold(P<0.01).(4)The expression level of ?-Glu4 was the highest at 24?48 h after fed on B.vulgaris var.cicla,which separately was 15.19?9.36 times of that of control.The expression level of ?-Glu4 was the highest after starvation,which was 37.18 times to control(P<0.05).(5)The expression level of a-Glu was the highest after 48 h of starvation,which was 3.58 times to control(P<0.01).(6)After fed on A.sessilis the expression level of Lip5 was higher than that of the control.The expression level of Lip8 was the highest after starvation 48 h,which was 6.12 times to control.