Interference and Mechanism of Dill Seed Essential Oil and Contribution of Carvone and Limonene in Preventing Sclerotinia Rot of Rapeseed

<div><p>This study aimed to evaluate the inhibitory effects of dill (<i>Anethum graveolens</i> L.) seed essential oil against <i>Sclerotinia sclerotiorum</i> and its mechanism of action. The antifungal activities of the two main constituents, namely carvone and limonene, were also measured. Mycelial growth and sclerotial germination were thoroughly inhibited by dill seed essential oil at the 1.00 μL/mL under contact condition and 0.125μL/mL air under vapor condition. Carvone also contributed more than limonene in inhibiting the growth of <i>S</i>. <i>sclerotiorum</i>. Carvone and limonene synergistically inhibited the growth of the fungus. <i>In vivo</i> experiments, the essential oil remarkably suppressed <i>S</i>. <i>sclerotiorum</i>, and considerable morphological alterations were observed in the hyphae and sclerotia. Inhibition of ergosterol synthesis, malate dehydrogenase, succinate dehydrogenase activities, and external medium acidification were investigated to elucidate the antifungal mechanism of the essential oil. The seed essential oil of <i>A</i>. <i>graveolens</i> can be extensively used in agriculture for preventing the oilseed crops fungal disease.</p>