Effect Of ?-1,3-mannosyltransferase Gene FpALG3 On The Growth And Pathogenicity Of Fusarium Pseudograminearum

Wheat Crown Rot is a worldwide disease caused by many pathogens and the main pathogens are Fusarium graminearum,Fusarium cu1 morum,and Fusarium pseudograminearum.In Australia,F.pseudograminearum is the main cause of Crown Rot.Noteworthy,in the Huanghuai wheat area of China,Crown Rot has became increasingly serious,one of the most important of serious is F.pseudograminearum.However,Most of the studies only stay in its morphology or classification,and few study focused on the mechanism of its pathogenesis so far.In this paper,the molecular mechanism of the infection process of F.pseudograminearum will be revealed in the N-glycosylation of protein.At present,previous studies have shown that protein glycosylation plays a key role in regulating the growth,reproduction and development of mycelium of pathogenic fungi.These key genes of glycosylation play an essential role in the pathogenesis of pathogenic fungi.This paper explored the molecular mechanism of F.pseudograminearum infection in the process of protein Nglycosylation.Based on the results of transcriptome analysis of wheat infected by F.pseudograminearum,it was found that differential expression of a homologous gene Fp ALG3 on the N-terminal glycosylation pathway of secreted proteins modified mannotransferase.Through these datas,we know that the Fp ALG3 gene contains 1409 nucleotides,with 2 introns and 432 amino acids residues.Therefore,the gene of ?-1,3-mannosytransferase is selected as the focus of this study.In this paper,we use the reverse genetics research idea,the hygromycin-resistant transformants were obtained through gene knockout techniques.Further PCR screening of the ?fpalg3 deletion mutants was carried out by four pairs of primers,then confirmed by Southern Blot analysis.After that,the Fp ALG3 gene was recombined by homologous recombination into the knockout mutants through protoplast transformation to obtain the complemented transformants,which were confirmed to be true by their phenotype,pathogenicity,and PCR validation.The ?fpalg3 knockout mutants showed significant differences in growth traits compared to the wild type: slow growth,irregular colony growth,light yellow pigmentation,reduced conidia production by more than 90%,and more bifurcations at the edges of colonies.The pathogenicity experiments on barley leaves,wheat coleoptiles and wheat roots in pot showed that the mutant exhibited significant small size,short extent lesions,no inhibition on root,respectively,compared to wild-type.Cterminal GFP fusion fragment of Fp ALG3 gene with 2kb native promoter was successefull complement the phenotype of deletion mutant.Taken together,?-1,3-mannosytransferase in F.pseudograminearum plays an important role in regulating the vegetative growth,conidiation,and the infection of hosts.Fp ALG3 gene of F.pseudograminearum might be the determinant factor of pathogenicity functioning in the early infection stage.