Functional Characterization Of Kin4 Kinase And Its Conserved Amino Site In Fusarium Graminearum

Fusarium head blight?FHB?,mainly caused by Fusarium graminearum,is a very significant disease among wheat production.It could cause yield losses,and infected wheat grains have poor commodity value.Besides,it could produce some mycotoxins which are detrimental to our human being and domestic animals when their quantity over a criterion.Moreover,the resistant strains of FHB are difficult to breed,and until now,there still do not have immune or highly resistant strains.Therefore,it is possible to provide theoretical basis for the prevention of FHB by studying the pathogenic mechanism of Fusarium graminearum.As a result of this,yield losses caused by FHB could be controlled and reduced.KIN4 is a kind of serine/threonine protein kinase which has a conservative kinase domain.At present,the function of KIN4 in yeast has been studied more clearly,it was reported to have a strong relationship with mitosis.In budding yeast,when the spindle is mispositioned in the anaphase,KIN4 could prevent exit from mitosis by inhibiting mitotic exit network?MEN?,and thus significantly reducing the amount of cell with no nuclear or two nuclears.This research through sequenced the of secretory protein Fg592 mutants found that there is an amino acid missing on FgKIN4,and it could cause significant phenotypic defection just because of the lack of the this amino acid.In order to understand the functions of FgKIN4gene and this single amino acid,this research studied a series of phenotypes between Fgkin4and amino acid missing mutant Fgkin4^375K,and found that Fgkin4 had a decrease of 27%in growth rate when compared with the wild type;The length of conidium increased by about 30%where the production of conidium was not seen any drastic change;The ability of producing DON fell by 44%in infected wheat grains;The pathogenicity fell by 94%in infecting wheat spikes and 80%in infecting corn silks respectively;And Fgkin4 unable to produce perithecia completely.All the phenotypes of Fgkin4^375K are exactly the same as Fgkin4.In addition,through subcellular localization of,we found that FgKin4 could locate in the septum of hyphae and spores where FgKin4^375K could locate in the same place with FgKin4,but the green fluorescent was obviously weaken than it in FgKin4.By qRT-PCR,the expression of FgKIN4 gene in Fgkin4^375K was reduced by 33%when compared to Fgkin4 comp,the complementary strains of Fgkin4.Finally,FgKin4 and FgKin4^375K also had a slight difference in protein structure.It indicated that missing amino acid play a important role in maintaining the protein structure of FgKin4.