Fusarium verticillioides is one of the most important fungal pathogens to cause destructive diseases of maize worldwide.Fumonisins produced by the fungus are harmful to human and animal health.In Fusarium verticillioides, conidia are the primary inoculum and the main source for disease dissemination in the field.In this study, we identified and characterized the Fvmcml gene that was disrupted in two mating mutants called FGSC7603 (FvA149) and FGSC7600 (FvA102) producing abnormity microconidian.27% and 14.55% abnormity microcondian were produced in FvA149 and FvA102 mutants 149-20 or 102-44, respectively.Deletion of FvMCM1 resulted in the loss of perithecium production and FB1.It rarely produced macroconidia that were abnormal in conidium morphology.Interestingly, during microconidium germination, we noticed that the Fvmcm1 mutant (102-44) often produced microconidia instead of germ tubes at early stages.The Fvmcm1 mutants were reduced to approximately 30% in the production of microconidia in 5-day-old CMC cultures.In yeast two-hybrid assays, FvMCM1 interact with MAT1-1-1 but not with MAT1-2-1.The Fvmcm1 mutant was defective in phialide formation and defective in self-inhibition of conidium germination.These results demonstrate that FvMcm1 plays critical roles in the regulation of sexual across, condia development, fumonisin biosynthesis.