Exploring the genetic and physiological effects of EMS mutagenesis on Fusarium proliferatum: Implications for Pokkah Boeng disease management, nitrogen metabolism, and secondary metabolites production

Ethyl methanesulfonate (EMS) mutagenesis is a common technique for developing genetic diversity in microorganisms. The present study investigates the genetic and biological effects of EMS mutagenesis in Fusarium proliferatum ( F. proliferatum ), the causative agent of Pokkah Boeng Disease (PBD) of sugarcane in China. F. proliferatum wild-type strain (PB6-3) was treated with different EMS concentrations of 0.0%, 1.0%, 2.5%, 5.0%, and 7.5%, and exposure times were kept at 30, 60, 90, and 120 minutes (mins) for the development of EMS mutagenesis. The EMS-mutagenized strains were screened for changes in virulence using detached sugarcane leaf assays. The strain with the most notable mutations relative to PB6-3, denoted MPB6-3, showed reduced virulence, an altered phenotype, and reduced growth and sporulation. Molecular markers were used to validate the successful induction of EMS mutagenesis in MPB6-3, and subsequent research showed that varying nitrogen (N) sources affected growth and sporulation rate, as well as the synthesis rate of secondary metabolites (SMs), e.g., phytohormones and mycotoxins. The study showed that N sources significantly affected metabolic rates in both PB6-3 and MPB6-3. Notably, the MPB6-3 showed varied rates of N assimilation. The results highlighted the applicability of EMS mutagenesis for developing biological mutants with altered virulence and metabolite profiles, and also provided valuable insights into F. proliferatum , enabling the development of a novel disease control strategy for sugarcane.