The Research On The Function Of Rdrp Gene In Fusarium Oxysporum F.Sp.Conglutinans

RDRP protein is formed by RNA as a template to form complementary RNA,which is an important amplification signal molecule in RNAi.In plant pathogenic fungi,RDRP protein is a global regulator.In many filamentous fungi,it has been found that it can regulate both sexual sporulation and asexual sporulation,and can also regulate the changes of metabolites.Cabbage blight is a soil-borne disease caused by Fusarium oxysporum f.sp.Conglutinans,which is harmful to cabbage industry.Preliminary studies in our laboratory found that RDRP protein was related to the growth,development and pathogenicity of Fusarium oxysporum.In order to further explore the mechanism of Rdrp gene in Fusarium oxysporum,based on the bioinformatics analysis of Rdrp gene,Fusarium oxysporum f.sp.Conglutinans,the mucin-specified Fusarium oxysporum physiology No.1 race FOX-A8 wild type and its RDRP1and RDRP2 deletion mutant(FOX-A8-?Rdrp1,FOX-A8-?Rdrp2)spores were used as materials for compare growing developmentt,metabolome,pathogenicity and resistance to cabbage.1.In Fusarium oxysporum RDRP1 protein,the?helix is the most,and the?helix is connected by short loop or?folding strand,and the?fold is the most in RDRP2 and RDRP3,forming the?propeller structure.functionally,they are non-transmembrane hydrophilic proteins with multiple phosphorylation sites,and the subcells are located in the intima and may have signal transduction function or participate in related signal transduction pathways.The evolutionary analysis of the RDRP protein sequence of Fusarium oxysporum and 30 other fungi showed that the sequence similarity of RDRP protein was as high as 87.08%,and there was some differentiation in evolution,which indicated that they performed different functions in Fusarium oxysporum.2.On PDA medium,the mycelium growth rate of Rdrp1 deletion mutant became slower,the colony edge was neat and dense,the mycelium branched more and the extension growth slowed down,while in PDB culture medium,the conidia of Rdrp deletion mutant became smaller and changed from short rod to nearly spherical.The mycelium of the Rdrp1 deletion mutant strain grew less and gathered in the petri dish,the mycelium of the Rdrp2 deletion mutant strain broke more than that in PDA,and the pigment production of the FOX-A8-Wild,Rdrp2 deletion mutant strain was less than that of the FOX-A8-Wild,Rdrp2 deletion mutant strain on VBC medium,and the color was light yellow.On the medium without H₂O₂,the FOX-A8-Wild and Rdrp1deletion mutants were completely inhibited,while the Rdrp2 deletion mutants grew slowly.3.The metabolic groups of FOX-A8-Wild and Rdrp deletion mutants were compared,and the results showed that.The differential metabolites screened by B v A,C v A and B v C in positive ion mode were 139,131,137 respectively.It was found that compared with FOX-A8 wild type could cause changes in the number,species and content of a large number of metabolites between wild-type and mutant strains of Fusarium oxysporum.Among the screened differential metabolites,organic acids,amino acids,esters,carbohydrate metabolites,alcohols,phosphates and lipids and amine metabolites are regulated by Rdrp gene,in which organic acids and amino acid metabolites play an important role in sporulation of Fusarium oxysporum.The differential metabolites involved were significantly enriched in organic acid metabolism,amino acid metabolism,ester metabolism,sugar metabolism,alcohol metabolism and phosphate metabolism pathway.It has been confirmed that organic acids and amino acid metabolites are closely related to the sporulation of Fusarium oxysporum,which is consistent with the results in 2.4.Using Brassica oleracea L as material,the pathogenicity and resistance of cabbage treated with metabolites of FOX-A8-Wild and Rdrp deletion mutants and pathogens were compared.The results showed that compared with the control group,the whole plant wilted until death occurred in all treatments from 9 to 12 days.The morphogenesis and substance accumulation of cabbage treated with pathogens were significantly lower than those of the control group.However,the morphogenesis and substance accumulation of cabbage plants treated with metabolites were significantly lower than those treated with bacterial suspension,showing a trend of increase at first and then decrease.The permeability regulating substances in the treatment group increased at first and then decreased.Especially in the later stage of infection,the content of soluble protein in cabbage decreased significantly.The index of stress resistance was significantly higher than that of the control.However,the activities of three antioxidant enzymes treated with metabolites were significantly lower than those treated with bacterial suspension.All of them showed a trend of increasing at first and then decreasing.To sum up,we believe that RDRP protein may regulate organic acid and amino acid metabolites and their participating organic acid metabolism and amino acid metabolic pathways through small RNA,thus affecting the conidia morphology and sporulation mode of Fusarium oxysporum,and regulating toxin metabolites and their metabolic pathways,thus affecting the pathogenicity of Fusarium oxysporum.