Effects and possible mechanisms of tea tree oil vapor treatment on the main disease in postharvest strawberry fruit

The purpose of this study was to investigate the effect of tee tree oil (TTO) against the main fungal disease in strawberries and a possible mechanism for the effects. TTO vapor exhibited a higher activity against spore germination and mycelial growth of Botrytis cinerea and Rhizopus stolonifer under in vitro conditions. TTO vapors at 0.9 g/L significantly reduced artificially inoculated gray mold and soft rot in vivo, and treated strawberries maintained a fresher quality than untreated strawberries during storage. In addition, this treatment also enhanced the resistance of strawberries against B. cinerea, which caused a higher hydrogen peroxide (H2O2) level and activities of superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), peroxidase (POD) and β-1,3-glucanase during the first period of incubation. These results indicate that TTO can reduce fruit decay, possibly by inhibiting pathogen growth directly and inducing disease resistance indirectly, and TTO vapor may provide an alternative means of controlling disease in strawberries.

► Tea tree oil (TTO) vapor treatment alleviated gray mold and soft rot in strawberries. ► TTO vapor treatment maintained a higher quality of freshness than untreated fruit in storage. ► Spore germination and mycelial growth of Botrytis cinerea and Rhizopus stolonifer were inhibited by TTO. ► TTO induced H2O2 levels and SOD, PAL, POD and β-1,3-glucanase activities in strawberries.