Study On The Mechanism Of Antifungal Action Of Fenprofenone

The pathogenic is one of the main dieases of agricultural disasters,which causing150 billion kilogramsof food loss every year.The biological fungicide Psoralea corylifolia L.seed extract was used in agricultural production to control various plant diseases such as rice blast,Valsa mali,Fusarium moniliforme Sheld and Colletotrichum orbiculare v.Arx.Studies have shown that the seeds of Psoralea corylifolia L.contains bakuchiol,psoralen,psoralidin,bavachin and isobavachalcone,and other active ingredients.Isobavachalcone is a major active ingredient.In this study,we explored the mechanism of isobavachalcone against the rice blast fungus through transcriptomics,proteomics and computer simulation technology.The spore suspension of Pyricularia oryzae cultured for 5 days was subjected to transcriptome analysis after being treated with 10 mg/L Isobavachalcone for 2 hours,which found that the expression of pyruvate dehydrogenase complexes E1 component,pyruvate dehydrogenase E2 component,dihydrolipoamide dehydrogenase,2-oxoglutarate dehydrogenase E1 component,2-oxoglutarate dehydrogenase E2 component,pyruvate carboxylase of TCA cycle were down-regulated significantly.Then the expression of six genes were verified by RT-q PCR,which revealing that pyruvate dehydrogenase E1 component was the down-regulated significantly when treated with IBC at 0.5h.Meanwhile,the activity of pyruvate dehydrogenase E1 of the Pyricularia oryzae was measured by the method of 2,6-dichloroindophenol,which found that the pyruvate dehydrogenase activity of Pyricularia oryzae when treated with IBC was obvious lower than control group and the enzyme activity of pyruvate dehydrogenase in experimental groups were 0.87,0.8,0.74,0.62 and 0.45 times as much as the control group at 1h,2h,4h,8h and 16 h respectively.The 3D structure model of the pyruvate dehydrogenase from Pyricularia oryzae was established based on homology modeling,which was predicted active site.Molecular docking and molecular dynamics simulations were carried out to explore the interaction between isobavachalcone and pyruvate dehydrogenase.Results showed that isobavachalcone binds to the residue ASP217 of pyruvate dehydrogenase by hydrogen bonding,and has a pi-pi stacking effect with the residue TYR139,and these non-polar residues such as PHE111,VAL188,MET250 and HIS313 were able to form strong hydrophobic interactions.The average RMSD of the protein trend to be stable from80 ns during 100 ns molecular dynamics simulations,the complexes had certain conformational stability.Protein-ligand interactions are divided into three types:Hydrogen Bonds,Hydrophobic and Water Bridges,which giving a stable binding mode for isobavachalcone-pyruvate dehydrogenase.TMT quantitative proteomics found that the expression of some proteins in the Pyricularia oryzae changed significantly after treated with 10mg/L isobavachalcone for2 hours.FC > 1.2,FC < 0.83,p-value < 0.05 was the screening stanard of differential proteins in the two samples,which obtained 50 differentially expressed proteins,including 17 down-regulated differential proteins and 33 up-regulated differential proteins.These down-regulated proteins mainly affect the remodeling of fungal cell walls,inhibit the pathways of ribosome metabolism,glycolysis and signal transduction,making the mycelium gradually collapse and die.The up-regulated differential proteins mainly include some resistance proteins and heat shock proteins.The above underlying mechanism would be helpful to discover new drug targets and efficient fungicides.