Identification of root exudate components during the Fusarium graminearum-maize interaction and their antifungal activity
In order to clarify the effects of fungal pathogen Fusarium graminearum infection on the root exudates of maize,liquid chromatography-mass spectrometer(LC-MS)technology and non-targeted metabolomics were used to identify the differential components.The antifungal effects of these differen-tial components were further analyzed.The results showed that a total of 34 root exudate components were differentially expressed in response to F.graminearum infection,mainly including organic hetero-cyclic compounds,benzene and organic oxygen compounds.Among them,four components containing niflunic acid,ethyl caffeate,4-methyl-3-nitrobenzoic acid and vanillin acetate,exhibited significant in-hibitory effects on F.graminearum.The niflunic acid exerted the strongest antifungal activity against F.graminearum.The inhibitory rate of 100 μg/mL niflunic acid on spore production and spore germina-tion reached 96.0%and 87.0%,respectively.In addition,vanillin acetate treatment caused reactive oxy-gen species(ROS)accumulation in the mycelium of F.graminearum;niflunic acid and 4-methyl-3-ni-trobenzoic acid treatments not only induced ROS accumulation in the spores of F.graminearum,but al-so caused cell death of mycelium and spores.Taken together,the four components have the potential to control maize stem rot.