Ammoides pusilla Essential Oil: A Potent Inhibitor of the Growth of Fusarium avenaceum and Its Enniatin Production

Abstract

Enniatins are mycotoxins produced by Fusarium species contaminating cereals and various agricultural commodities. The co-occurrence of these mycotoxins in large quantities with other mycotoxins such as trichothecenes and the possible synergies in toxicity could lead to serious food safety problems. Using the agar dilution method, Ammoides pusilla was selected among eight Tunisian plants for the antifungal potential of its essential oil (EO) on Fusarium avenaceum mycelial growth and its production of enniatins. Two EO batches were produced and analyzed by GC/MS-MS. Their activities were measured using both contact assays and fumigant tests (estimated IC50 were 0.1 µL·mL−1 and 7.6 µL·L−1, respectively). The A. pusilla EOs and their volatiles inhibited the germination of spores and the mycelial growth, showing a fungistatic but not fungicidal activity. The accumulation of enniatins was also significantly reduced (estimated IC50 were 0.05 µL·mL−1 for the contact assays and 4.2 µL·L−1 for the fumigation assays). The most active batch of EO was richer in thymol, the main volatile compound found. Thymol used as fumigant showed a potent fungistatic activity but not a significant antimycotoxigenic activity. Overall, our data demonstrated the bioactivity of A. pusilla EO and its high potential to control F. avenaceum and its enniatins production in agricultural commodities.

Characterization of Fusarium acuminatum: A Potential Enniatins Producer in Tunisian Wheat

“…The mycelial growth inhibiting effect of TC EO was higher than that of AP EO for both species. The same level of inhibition of ENNs’ accumulation in the FDM-agar medium by F. acuminatum 33T was observed here for both EOs, whereas AP EO was more effective than TC EO for F. avenaceum [ 15 ]. The effectiveness of AP and TC EOs on two members of the F. tricinctum complex is a strength for their putative use for controlling these ENN producers and limiting the accumulation of the mycotoxins in plant products.…”

“…The antifungal activity of the same eight EOs from Tunisian plants used ( Figure 5 ) here was previously tested against a strain of F. avenaceum , which was significantly more affected by AP and TC EOs than by the other EOs [ 15 ], as F. acuminatum 33T was in the present study ( Figure 5 ). The mycelial growth inhibiting effect of TC EO was higher than that of AP EO for both species.…”

“…The latter point is primordial for the development of different formulations to potentialize the EOs as the scale-up of their production in the aim of field application is a complicated task. Finally, the determination of the contribution of different compounds constituting an EO in its biological activity provides a better understanding of the different interactions among the compounds and their activity [ 15 , 44 ]. Hence, formulations focusing on the mixture of the main active compounds in their synthetic form is a promising area of investigation to provide biofungicide alternatives.…”

“…The effects of EOs from eight Tunisian plants (Ammoides pusilla, Artemisia absintum, Carum carvi, Mentha spicata, Myrtus communis, Origanum vulgare, Schinus terbentofonius, Thymus capitatus) on the mycelial growth and production of ENNs by one of the isolates, F. acuminatum 33T, were measured in FDM-agar as described by Chakroun et al [ 15 ] and in Section 2.7 . Briefly, the EOs were diluted at 0.1 µL mL −1 in FDM-agar medium poured into 90 mm Petri dishes.…”

“…The use of non-toxic and eco-friendly plant essential oils (EOs) is one alternative. Some EOs have been shown to be effective against Fusarium species and their production of mycotoxins [ 12 , 13 , 14 , 15 ]. Finding alternatives to synthetic fungicides for controlling local populations of Fusarium spp.…”