Effects of exogenous jasmonic acid on the metabolites of Panax notoginseng（Burk.）F. H. Chen root system and the induction of disease resistance in Panax notoginseng（Burk.）F. H. Chen by key metabolites

【Objective】This study aimed to inresligate the metabolic changes of Panax notoginseng（Burk.）F. H. Chen root system induced by jasmonic acid（JA）spraying on leaves，and clarify the significantly changed metabolites， so as to provide a basis for biological control of P. notoginseng diseases.【Method】P. notoginseng was used as experiment materials. This study determined the content of endogenous hormone JA in P. notoginseng after inoculation on leaves with Alternaria panax strain SL17 for 4 and 8 d. Metabolic changes in P. notoginseng root system were analyzed by using gas chromatography-mass spectrometry（GC-MS）after exogenously spraying on leaves with different concentrations of JA. This study measured the effects of significantly changed metabolites on resistance against major root rot pathogens and the induction of black spot disease resistance in P. notoginseng after root irrigation.【Result】The content of JA and Jasmonic acid leucine chelate（JA-ile）in the leaves increased while the content of the both substances in the root system decreased after inoculation on leaves for 4 d. The content of JA in the leaves was significantly increased（P＜0.05，the same below），and the contents of two substances in root system were extremely significantly increased（P＜0.01）after inoculation for 8 d.After exogenously spraying different concentrations of JA， the metabolism change analysis of P. notoginseng root system showed that 125 metabolites were detected in the root system of P. notoginseng，mainly categorized as organic acids， amino acids， esters， sugars， amines， nucleotides and their derivatives and ketones， of which sugars， organic acids and amino acids were the main components. Compared with the blank control，the content of oxalic acid and dihydroorotic acid in the root system of P. notoginseng increased significantly after exogenously spraying JA on the leaves. Further study on significantly changed differential matebolities revealed that oxalic acid and dihydroorotic acid had certain inhibitory effect against the major root rot pathogens of P. notoginseng. Among them，dihydroorotic acid with the concentration of 0.001 μg/mL had the best inhibitory effect against Fusarium solani strain F3 and Ilyonectria destructans strain RS6. Dihydroorotic acid with the concentration of 0.010 μg/mL had the best inhibitory effect against I. destructans strain RS8. Dihydroorotic acid with the concentration of 0.100 μg/mL had the best inhibitory effect against Phytophthora cactorum strain D-6. Oxalic acid with the concentration of 0.001 μg/mL had the best inhibitory effect against F. solani strain F3. Oxalic acid with the concentration of 10.000 μg/mL had the best inhibitory effect against P. cactorum strain D-6. Oxalic acid and dihydroo-rotic acid significantly reduced the lesion area of black spot disease on leaves of P. notoginseng after root irrigation and represented the most induction of disease resistance in the concentration of 10.000 μg/mL.【Conclusion】Exogenously spraying JA can alter P. notoginseng root system metabolism and promote the accumulation of dihydroorotic acid and oxalic acid，which enhance plant resistance against black spot disease and show inhibitory effect against main root rot pathogens.