| In the evolution of linear genomes,it is crucial to protect the ends of natural chromosomes to prevent triggering of DNA damage repair mechanisms and enzymatic attack.Telomeres are tightly regulated complexes composed of repetitive G-rich DNA and specific proteins.The MRN complex is a major member of the repair mechanism and consists of the Mre11,RAD50 and NBS1 proteins.The protein encoded by the Rad50 gene regulates the activity of the MRN complex.The function of Rad50 in the pathogen of Fusarium graminearum is still unclear.The deletion mutant was obtained by the double-joint PCR method,and the growth rate of ?FgRad50 on the PDA medium was reduced by about 30%compared with the wild type and Complement returned to wild-type levels;the deletion mutant ?FgRad50 was reduced by 40%in the CMC compared with the wild type and Complement returned to wild-type levels;?FgRad50 Sexual reproduction was affected,and the vesicle shell produced by ?FgRad50 was reduced by half compared to wild type after black light induction and Complement returned to wild-type levels;?FgRad50 increased sensitivity to carbendazim,H2O2,caffeine and Mgig,and decreased sensitivity to tebuconazole and SDS.The pathogenicity was determined by connecting PH-1 and ?FgRad50 to field wheat ears.The results showed that the infectivity of the mutant was only infected at the inoculation point on the flowering wheat ear,the pathogenicity was significantly reduced,and ?FgRad50 The yield of deoxynivalenol was reduced by about 6 times,and this result should be confirmed.qRT-PCR was used to detect the transcription level of Tri gene in the process of inducing toxin production.It was found that in ?FgRad50,the expression level of Tri gene series was greatly reduced compared with wild type PH-1.In conclusion,the results of this study indicate that FgRad50 not only plays a key role in the regulation of fungal development,secondary metabolism and virulence,but also plays a key role in multiple stress responses in Fusarium graminearum. |
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