Activity of the botanical compound thymol against kiwifruit rot caused by Fusarium tricinctum and the underlying mechanisms

BACKGROUND Kiwifruit rot is an important disease caused by different fungal pathogens, which can lead to huge economic loss in the kiwifruit industry. The aims of this study were to discover an effective botanical compound that significantly inhibits the pathogens causing kiwifruit rot, evaluate its control efficacy against this disease, and reveal the underlying mechanisms. RESULTS A strain of Fusarium tricinctum (GF-1), isolated from diseased kiwifruit, could cause fruit rot in both Actinidia chinensis var. chinensis and Actinidia chinensis var. deliciosa . Different botanical chemicals were used for antifungal activity test against GF-1 and thymol was the most effective one with a 50% effective concentration (EC 50 ) of 30.98 mg L −1 . The minimal inhibitory concentration (MIC) of thymol against GF-1 was 90 mg L −1 . Control efficacy of thymol against kiwifruit rot was evaluated and the results indicated that thymol could effectively decrease the occurrence and spread of kiwifruit rot. The mechanisms underlying the antifungal activity of thymol against F. tricinctum were investigated, and it showed that thymol could significantly damage the ultrastructure, destroy the plasma membrane integrity, and instantaneously increase energy metabolisms of F. tricinctum . Further investigations indicated that thymol could extend shelf life of kiwifruit by increasing their storability. CONCLUSION Thymol can effectively inhibit F. tricinctum that is one of the causal agents of kiwifruit rot. Multiple modes of action are involved in the antifungal activity. The results of this study indicate that thymol can be a promising botanical fungicide to control kiwifruit rot and provide useful references for thymol application in agriculture system. © 2023 Society of Chemical Industry.