Functional Characterization Of The Enoyl CoA Hydratase In Fusarium Graminearum

Fusarium graminearum is the main pathogenic fungus of Fusarium head blight?FHB?,and its host is mainly cereal crops.It can cause the decrease of yield and quality of wheat.The residues of mycotoxins?deoxynivallenol,DON?cause serious damage to human and animal health.At the same time,it is also the important pathogenic factor which plays an important role for pathogenesis in wheat.Enoyl-CoA hydratase?Ech1?can degrade fatty acid to acetate units which is a critical process in?-oxidation.However,little is known about its functions in plant pathogenic fungi.Here we characterized an Ech1 orthologue FgEch1 in F.graminearum.In this study,bioinformatics method was used to get the one Fg Ech1 gene in genome of F.graminearum.We build knockout fragments of FgEch1 by Split-marker PCR;We get FgEch1 knockout mutant?Ech1 and replying strain?Ech1-C by PEG mediated the protoplast transformation.Studying the phenotypic changes of FgEch1 gene knockout mutants further can explain the function of FgEch1.The mutant has the following characteristics:1)The?Ech1 mutant has no effects on colony growth.2)Deletion of FgEch1??Ech1?affected the utilization of short chain fatty acids.Colony relative growth rate of mutant went down by 74.23%and 100%on the MM medium with butyric acid and caproic acid.However,on the MM medium with myristic acid,palmitic acid and oleic acid,its rate was decreased by 14.27%,13.12%and 8.28%,respectively.3)Deletion of FgEch1??Ech1?affected conidiation and conidial germination.Conidiation of the?Ech1 mutant was decreased by 80.19%compared with the WT.Moreover,the conidial germination declined by 56.85%and 13.25%at 6 h and 24 h,respectively.4)The?Ech1 mutant showed reduced virulence in wheat.The result of wheat head inoculation showed that the disease index of?Ech1 was decreased by 86.7%.5)The?Ech1 mutant increased tolerance to H₂O₂ stress.The mycelial inhibition rate of?Ech1 was increased by 7.533%,8.505%and 12.918%on CM medium supplemented with 0,1,5 and10m M H₂O_2.6)There was no significant difference on sexual reproduction between?Ech1mutant and PH-1.Taken together,These data indicate that mitochondrial FgEch1 is important for asexual reproduction,utilization of short chain fatty acids and plant infection.