The Systemic Resistance Of The Kidney Bean Induced By Frankliniella Occidentalis(Pergande)(Thysanoptera:Thripidae)

Western flower thrips,Frankliniella occidentalis(Pergande)(Thysanoptera:Thripidae),is a typical rasping-sucking mouthparts insect,which had caused great harm to vegetables,flowers and other economic crops in the world.There are many host plants of western flower thrips.Kidney bean,as the main host plant of western flower thrips,has been studied on defensive response,which showed that it could get local defensive response after feeding by western flower thrips.This study investigated the systemic resistance of the kidney bean plant induced by western flower thrips on biochemistry and molecule level,on the basis of previous studies of our research group.The local and systemic changes of the contents of secondary metabolism substance(tannins and flavonoids),the key defensive enzymes(lipoxygenase,LOX;phenylalanine ammonialyase,PAL and β-1,3-glucanase,PR-2)of the jasmonic and salicylic pathway and their corresponding defense genes(LOX,PAL and PR-2)were studied.The research shows that the western flower thrips feeding not only cause the defensive response of damaged leaves,but also of the healthy upper and lower leaves.The followings were the results:1.The contents of secondary metabolism substance at different parts of kidney bean leaves induced by western flower thripsThe contents of tannins and flavonoids in different parts of kidney bean leaves were all differently after feeding by western flower thrips.The contents of tannin in the leaves of damaged plants were not significantly induced.The contents of tannin in the damaged middle leaves was 3.12-fold as high as that of the control at 48 h,and1.64-fold as high as that of the control in the upper healthy leaves and 1.95-fold as high as that of the control in the lower healthy leaves at the same time.The contentsof flavo-noid in the damaged middle leaves and the upper healthy leaves reached the peak at 48 h in damaged plant,which were 4.81-fold and 2.88-fold as high as that of the control respectively.The contents of flavonoid in the lower healthy leaves of damaged plant reached the peak at 72 h,which was not significantly different with that of the control.2.The contents of the defensive enzyme activity at different parts of kidney bean leaves induced by western flower thripsThe enzyme activities of LOX,PAL and PR-2 were different in the kidney bean leaves after feeding by western flower thrips.The activities of LOX in e damaged leaves and lower healthy leaves of the damaged plant were not significantly different with that of the control.The activity of LOX in the upper healthy leaves reached the peak at 72 h,which was 4.22-fold as high as that of the control.The activity of PAL in the damaged leaves at 96 h decreased significantly.The activities of PAL in upper healthy leaves and lower healthy leaves in the same plant respectively reached the maximum at 24 h and 96 h,which were respectively 8.67-fold and 10.81-fold as high as that of the control.The activity of PR-2 was significantly suppressed at different parts of kidney bean leaves in the feeding plant.3.The expression of the defense genes at different parts of kidney bean leaves induced by western flower thripsThe expression levels of LOX,PAL and PR-2 in the damaged middle leaves,the healthy upper and lower leaves of kidney bean plant were all significantly induced by western flower thrips,but changed more rapidly in the damaged middle leaves.The expression modes of genes changed with time.The relative expression level of LOX in the damaged middle leaves was significantly higher than that of the control(non-inoculated leaves),and increased with the time extension,which was209.54-fold as high as that of the control at 96 h.The expression level of LOX increased first and then decreased and finally rose again in the healthy upper and lower leaves.The expression level of PAL reached the maximum in both damaged middle leaves and healthy upper leaves at 48 h after infestation of western flower thrips,which were 52.70-and 41.20-fold as high as that of the control,respectively.However,its expression level reached the peak at 72 h in the healthy lower leaves,which was 47.06-fold as high as that of the control.The expression level of PR-2reached the maximum at 48 h after infestation of western flower thrips in the healthy upper leaves,at 96 h in both damaged middle leaves and healthy lower leaves.PR-2was barely expressed in the healthy lower leaves at 24 h after infestation of western flower thrips.