Active compound identification by screening 33 essential oil monomers against Botryosphaeria dothidea from postharvest kiwifruit and its potential action mode

The antifungal activity of postharvest kiwifruit against the pathogen Botryosphaeria dothidea was evaluated for 33 essential oil monomers. The possible mechanism for the known active compounds were further assessed in this study. The results show all the EO components exhibit inhibitory effects on the pathogen to different degrees except for Farnesol. Carbon chain length and C-2-C-3 double bonds had a great effect on the antifungal activities of aldehydes. Of all of these, carvacrol had the strongest antifungal activity with EC50 of 12.58 mu L/L and EC90 of 22.08 mu L/L. Carvacrol also exhibits significant inhibitory effects on the pathogen, both in vivo and in vitro. Carvacrol evidently alters the hyphal morphology of B. dothidea and severely damages cell membrane and inhibits the formation of lipid components on the membrane. As cell membrane permeability increases, intracellular homeostasis including ion and biomacromolecules were destroyed by carvacrol. Furthermore, carvacrol appears to significantly inhibit mitochondrial activity and respiration rates, resulting in cell death of B. dothidea. Our results provide evidence that carvacrol could be a very useful compound for controlling postharvest rot soft in kiwifruit.