Efficacy of Cuminum cyminum essential oil on FUM1 gene expression of fumonisin-producing Fusarium verticillioides strains

OBJECTIVES The purpose of this study was to evaluate the effect of Cuminum cyminum (C. cyminum) essential oil on the growth and FUM1 gene expression of fumonisin-producing Fusarium verticillioides (F. verticillioides) strains isolated from maize. MATERIALS AND METHODS All fungal strains were cultured on potato dextrose agar (PDA) slopes at 30°C for 7 days. The antifungal activity was evaluated by broth microdilution assay. One set of primers was F. verticillioides species specific, which selectively amplified the intergenic space region of rDNA. The other set of primers was specific to FUM1 gene region of fumonisin-producing F. verticillioides. FUM1 transcript levels were quantified using a reverse transcription-polymerase chain reaction (RT-PCR) protocol. RESULTS Minimum inhibitory concentration (MIC) values of C. cyminum oil against F. verticillioides strains varied from 0.195 to 0.781 µl.ml(-1) (mean MIC value: 0.461 µl.ml(-1)) indicating 54.5% of the fungal strains inhibited at 0.390 µl.ml(-1). PCR analysis of FUM1 gene expression revealed that DNA fragment of 183 bp was amplified in all the isolates of F. verticillioides before treatment with C. cyminum essential oil. Based on RT-PCR analyses, reduction in the expression of fumonisin biosynthetic genes was significant only for FUM1 gene (p<0.05), while no effect was observed on ITS gene. CONCLUSIONS This study showed that all F. verticillioides isolates were susceptible to C. cyminum essential oil, indicating a significant reduction in the growth of fungal isolates. In addition, this oil completely inhibited the expression of FUM1 gene in concentrations dose-dependently.