Targeting Fumonisin Biosynthetic Genes.

Area of Science:

• Agricultural Science
• Mycology
• Molecular Biology

Background:

• Fusarium fungi cause significant agricultural losses through plant diseases and mycotoxin contamination.
• Species within Fusarium exhibit substantial variation in gene clusters responsible for mycotoxin synthesis and their genomic locations.
• Accurate identification and quantification of Fusarium species are crucial for disease management and food safety.

Purpose of the Study:

• To develop a quantitative real-time PCR (qPCR) assay for distinguishing and estimating the biomass of two closely related maize pathogens: Fusarium proliferatum and Fusarium verticillioides.
• To utilize the species-specific genomic location of the fumonisin biosynthesis gene cluster as the basis for the qPCR assay design.
• To validate the qPCR assay's efficacy in quantifying fungal biomass in both pure cultures and infected plant tissues.

Main Methods:

• Designed species-specific qPCR primers targeting unique sequences flanking the fumonisin gene cluster in F. proliferatum and F. verticillioides.
• Extracted DNA from pure cultures and maize seedlings inoculated with individual or mixed Fusarium species.
• Quantified Fusarium biomass using species-specific primers and maize biomass using maize-specific primers (targeting ribosomal gene L17).

Main Results:

• The developed qPCR assay successfully distinguished between F. proliferatum and F. verticillioides.
• The assay accurately estimated the biomass of each Fusarium species in pure cultures and infected maize seedlings.
• Biomass was reliably expressed as the ratio of Fusarium DNA to maize DNA, demonstrating the assay's quantitative capability.

Conclusions:

• Genetic variation in the presence and genomic location of secondary metabolite (SM) gene clusters is a valuable resource for developing precise qPCR diagnostic tools.
• The developed qPCR method provides an effective means for distinguishing and quantifying F. proliferatum and F. verticillioides in agricultural settings.
• This approach has broader implications for developing qPCR assays to identify and quantify other fungal pathogens in plants based on unique genetic markers.