Functional Analysis Of Succinate Dehydrogenases FgSdhC And FgSdhD In Fusarium Graminearum

Fusarium graminearum is one of the dominant species of wheat scab.The pathogen not only reduces the yield and quality of wheat crops,but also produces fungal toxins that can seriously harm human and animal health.control mainly depends on the control of SDHIs class（succinate ehydrogenase inhibitors）fungicide main targets for Ⅱmitochondrial respiratory chain complexes,is a key part of the tricarboxylic acid cycle.For the study of complex Sdh C and SdhⅡD subunits in grass valley sickle bacterium function,this study adopts the split-Marker PCR was used to knock out Fg Sdh C1,Fg Sdh C2 and Fg Sdh D in fusarium gramineae,respectively,to obtain the antihydantomycin inverters.Three mutants were identified by PCR,and the reconstructing strains were constructed,and their biotypic functions were analyzed respectively.The results showed that:1)The defective gene FgSdhC1 in fusarium graminis significantly reduced the growth rate of mycelia and increased the bifurcation in different media.The culture medium of mutant ΔFg Sdh C1 was light yellow,while the wild type ph-1 was magenta.Stress experiment found that lack of gene Fg Sdh C1 organism acyl amine and thiazole bacteria acyl hydroxylamine resistance performance,ester of carbendazim,cyanide ene,luo e listed the fungus nitrile become sensitive to the cell wall osmosis ions and metal ions,SDS,Congo red,H₂O₂,Na Cl and CaCl₂ sensitivity,reduced susceptibility to Caffeine,and cannot make corn stigma and grain,asexual sexual reproduction defects,mycelium SDH activity decline.The Fg Sdh C2 gene deletion mutants showed no significant differences in growth,sporulation,pathogenicity and SDH.2)Compared with wild-type ph-1 and backcomplement,mutants ΔFg Sdh D showed a reduced growth rate,dense mycelia at the edge of the colony,no conidia and ascospores were produced,and the medium was pale yellow,which could not infect the corn stalk and ear of wheat.Fg Sdh D,the defective gene of fusarium gramineae,was less sensitive to the agents diazolimide and fluzolamide,and more sensitive to carbendazim,cyanozoyl esters,pentazolidol and roslonitrile,as well as to stress factors SDS,Congo red,H₂O₂,Na Cl and CaCl₂,and also affected the activity of the mycelium SDH.These results suggest that Fg Sdh C1 and Fg Sdh D genes are involved in the growth and development of fusarium graminis,cell wall integrity,pigment synthesis and pathogenicity.There was no significant change in Fg Sdh C2 of fusarium graminis.The results provide a theoretical basis for searching for new drug targets to inhibit fusarium gramineae,elucidate the pathogenic molecular mechanism of pathogenic fungi and study the resistance mechanism of fusarium gramineae to SDHIs fungicides.