Effect of ethanol treatment on disease resistance against anthracnose rot in postharvest loquat fruit

• Ethanol reduced disease incidence of anthracnose rot in postharvest loquat fruit.
• Ethanol treatment induced activities of several defense enzymes.
• Ethanol treatment inhibited the growth of C. acutatum.
• Decay reduction was due to the pathogen growth inhibition and disease resistance induction.

The effect of ethanol treatment on disease resistance against anthracnose rot in postharvest loquat fruit and its possible mechanism were investigated. Our data implied that treatment of loquat fruit with ethanol at 300 μl/l significantly inhibited the anthracnose rot caused by Colletotrichum acutatum and maintained the overall quality. Ethanol treatment suppressed activities of catalase and ascorbate peroxidase while increased superoxide dismutase activity in C. acutatum-inoculated loquat fruit, thus resulting in a higher level of H2O2, which might serve as a crucial role to activate disease resistance. Meanwhile, the activities of defense-related enzymes including phenylalanine ammonia-lyase, peroxidase, polyphenol oxidase, chitinase and β-1,3-glucanase were significantly enhanced by the ethanol treatment. In addition, 300 μl/l ethanol exhibited an effective antifungal activity against spore germination and mycelial growth of C. acutatum in vitro. Therefore, these results suggest that ethanol can inhibit anthracnose rot in postharvest loquat fruit, possibly via inhibiting pathogen growth directly and inducing disease resistance indirectly.