Study On The Mechanism Of Exogenous Application Of Ginsenoside Rg₁ To Enhance The Pathogenicity Of Fusarium Solani On Ginseng

Ginseng（Panax ginseng CA Meyer）is a perennial herbaceous plant in the Araliaceae family.Ginseng root rot is one of the most important reasons affecting the ginseng cultivation,and it is an urgent problem in production.In this study,ginseng in Northeast China was used to isolate and identify the pathogen of ginseng root rot,screen out the Rg₁ concentration that best induces the pathogen of ginseng root rot,and explore the optimal Rg₁ concentration to infect or defend against ginseng root rot.The influence of related enzyme activity and the effect on the activity of ginseng-related enzymes.Ginseng root rot fungus is affected by Rg₁ inducing conditions on ginseng infection or defense related enzyme activities,and transcriptome sequencing further reveals that Rg₁ induces ginseng root rot fungus to enhance the effect the molecular mechanism of the pathogenicity of ginseng.The contents of this paper are as follows:（1）The root rot pathogen of 130 ginseng strains in 6 regions was isolated,and the pathogen of ginseng root rot was isolated and identified.After morphological identification combined with molecular biological identification,the pathogen was determined to be Fusarium solani.（2）The growth rate method,the spore germination method,and the hyphal dry weight method were used to determine the chemotaxis of different concentrations of Rg₁ on the pathogen of ginseng root rot.The test results showed that when the concentration of Rg₁ was 5mg·L^-1,the chemotaxis of ginseng root rot fungi was the strongest,the mycelial growth promotion rate was 3.466%（P<0.05）,and the spore germination rate（SGR）was 35.17%on the 4th day.（P<0.05）,the dry weight of mycelium is 946.11±12.7297 mg（P<0.05）.（3）The optimal concentration affects the enzyme activity.According to the selected optimal concentration,the test group is set to determine peroxidase（POD）,polyphenol oxidase（PPO）,catalase（CAT）,and phenylalanine Acid ammonia lyase（PAL）,lipoxygenase（LOX）and superoxide dismutase（SOD）6 kinds of defense or infection-related enzyme activity changes.The results showed that when the concentration of Rg₁ was 5 mg·L^-1,the activities of the six enzymes increased to varying degrees（P<0.05）.（4）Determination of the defense or infection-related enzyme activities of ginseng plants and ginseng seedlings under different treatments with different concentrations of Rg₁.Under the aseptic treatment of different Rg₁ concentrations,when the Rg₁ concentration of ginseng plants is 2 mg·L^-1,the cellulase,pectinase,cutinase,and amylase activity concentrations all increase significantly,and the effect on ginseng plants is significant（P<0.05）.For ginseng seedlings,when the Rg₁ concentration was 10 mg·L^-1,the cellulase and pectinase activity concentration increased significantly（P<0.05）,and when the Rg₁ concentration was 2 mg·L^-1,the cutinase activity concentration increased significantly（P<0.05）.（5）Treatment of ginseng root rot fungi with different concentrations of Rg₁,when the Rg₁concentration is 10 mg·L^-1,the activity concentrations of cellulase,pectinase,cutinase,and amylase all increase significantly,which has the most inducing effect on Fusarium solani Obviously（P<0.05）.When the Rg₁ concentration of ginseng seedlings was 10 mg·L^-1,the activity concentrations of cellulase,pectinase,and cutinase all increased significantly（P<0.05）.（6）Transcriptome sequencing of ginseng samples at different periods under Rg₁ treatment,a total of 36.27 Gb Clean Data was obtained.The Clean Reads of each sample is compared with the designated reference genome,and the comparison rate ranges from 28.68%to 95.87%.A total of 69546 expressed genes were detected in this analysis,including 34401 known genes and 35145 new genes.There are 119041 expressed transcripts,including 29894 known transcripts and 89147 new transcripts.In the clustering heat map analysis of ginseng samples at different periods under Rg₁ treatment combined with Phi library analysis,30 functional genes with significant differential expression among the preferred groups were screened,including 2pathogenicity-enhancing genes and pathogenicity-loss genes 4,10 genes attenuated pathogenicity.