| Fusarium head blight(FHB)is one global crop desiease that affects food yeild and security.Under suitable climate,the disease uaually prevails in a large area and hard to be controlled.In China,Fusarium graminerium is the main pathogen of FBH.Due to the lack of resistant resources,today chemical pestcide is the main“weapon”to control FHB,which can control the desiease in some degree but has the risk of large area break out.So,it’s important to search the pathogenic mechanism of F.graminerium deeply.cAMP-dependent protein kinase A(cAMP-PKA)is one wide distributed and conserved kinase in eukaryote.It regulates cell activity in many processes,such as cell growth and response to nutrients and stress,et.PKA also plays a role in pathogenic process of fungi.In F.graminerium,two genes named CPK1 and CPK2 encode the catalytic subunits of PKA.The cpk1cpk2 double mutant was significantly reduced in vegetative growth,conidiation and totally lost the ability of perithecium formation,wheat infection and deoxynivalenol(DON)production.The cpk1cpk2 double mutant can produce spontaneous suppressors on PDA plate.In this study we totally collected 25 sectors.Compared with the cpk1cpk2 double mutant,the sectors were totally recovered in colony morphology,and partially recovered in sexual reproduction and wheat infection,and produced less conidia.Through whole genome sequencing,we identified the mutant gene FgSFL1 in sectors.Combined with normal sequencing,we found that all the 25 sectors have mutations in FgSFL1,totaly at 10 sites,9 of which result in the frame-shift or termination mutation in FgSfl1 protein,which seriously affect the protein function.The deletion of FgSFL1 can suppress the morphology of cpk1cpk2 double mutant.The deletion mutant of FgSFL1 in PH-1 had defects in conidiation,sexual process and plant infection.Comparing the function of FgSFL1 in cpk1cpk2 double mutant and the wild type,we can see that,FgSFL1 can negetively control colony morphology,positively control conidiation and has both positive and negetive effection on sexual process and pathogenicity.We respectively construct site-mutation mutant in 3 putative PKA phosphoralation sites,and found that FgSFL1~S559D559D mutation can result in less conidiation and fewer perithecia.So we can speculate that S599site of FgSfl1 maybe one important phophoralation site of PKA. |
