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

Abstract

Objectives: The purpose of this study was to evaluate the effect of <em>Cuminum cyminum</em> (<em>C. cyminum</em>) essential oil on the growth and <em>FUM1 </em>gene expression of fumonisin-producing <em>Fusarium verticillioides</em> (<em>F. verticillioides</em>) strains isolated from maize. <br/>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 <em>F. verticillioides</em> species specific, which selectively amplified the intergenic space region of rDNA. The other set of primers was specific to<em> FUM1</em> gene region of fumonisin-producing <em>F. verticillioides. FUM1 </em>transcript levels were quantified using a reverse transcription-polymerase chain reaction (RT-PCR) protocol. <br/>Results: Minimum inhibitory concentration (MIC) values of <em>C. cyminum</em> oil against <em>F. verticillioides</em> 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 <em>FUM1</em> gene expression revealed that DNA fragment of 183 bp was amplified in all the isolates of <em>F. verticillioides</em> before treatment with <em>C. cyminum</em> essential oil. Based on RT-PCR analyses, reduction in the expression of fumonisin biosynthetic genes was significant only for <em>FUM1 </em>gene (<em>p</em><0.05), while no effect was observed on <em>ITS</em> gene. <br/>Conclusions: This study showed that all <em>F. verticillioides</em> isolates were susceptible to <em>C. cyminum</em> essential oil, indicating a significant reduction in the growth of fungal isolates. In addition, this oil completely inhibited the expression of <em>FUM1 </em>gene in concentrations dose-dependently.