Relationship between root exudates of grafted eggplants and Verticillium wilt resistance and their components identification

Effect of grafting on soil-borne disease(Verticillium wilt) resistance of eggplants was studied in this paper.The root exudates of grafted eggplants were collected with root soaking method.Components and contents of root exudates of grafted eggplants were determined by Gas chromatography/mass spectrometry,and the components′ variation of root exudates by grafting was analyzed.Effects of root exudates and their simulated allelochemicals on mycelium growth of Verticillium dahliae were studied.The relationship between root exudates of grafted eggplants and their resistance to Verticillium wilt was discussed.The results showed that grafted eggplants showed a decrease of disease incidence of Verticillium dahliae.The amounts of Verticillium dahliae in soil were significantly lower in grafted eggplant treatment than in self-rooted eggplant treatment with the development of eggplants.Mycelium growth was also inhibited by the root exudates of grafted eggplants.GC-MS analysis indicated that grafting changed the components of root exudates of eggplants.Hydrocarbon,ester,acohol,phenol,ketone,benzene and amine were detected in the root exudates of grafted eggplants,while acohol,benzene and amine were not in the root exudates of self-rooted eggplants.Alkyne and phenanthridine were detected in the root exudates of self-rooted eggplants,but not in grafted eggplants.The content of phenol(a allelochemical) in root exudates was lower in grafted eggplant treatment than in self-rooted eggplant treament.Effects of simulated root exudates of eggplants on mycelium growth of Verticillium dahliae showed that inhibitory effect of dibutyl phthalate on mycelium growth of Verticillium dahliae increased at concentrations ranging from 0.05 0.5 mmol.L-1,and reduced at the higher concentration.Inhibitory effects of tetradecanoic acid and hexadecanoic acid exhibited a decrease trend at the lower concentration range and an increase at the higher concentration range.