Hexanal-containing dip treatment enhances kiwifruit resistance to Botrytis cinerea

This study evaluated the effectiveness of a hexanal-based enhanced freshness formulation (EFF), containing antioxidants such as geraniol, α-tocopherol and ascorbic acid, to inhibit the fungal decay caused by Botrytis cinerea in ‘Y368’ kiwifruit. In vitro and in vivo experiments using three treatments: control (untreated), 0.03 and 0.06 % (v/v) EFF were set up. In the in vitro experiment, mycelial growth and spore germination of Botrytis cinerea exposed to EFF were examined. In the in vivo experiment, disease incidence, lesion diameter, activity of defense-related enzymes (Phenylalanine Ammonia Lyase, Guaiacol Peroxidase, β-1,3-glucanase and Chitinase), total phenolics and flavonoids were evaluated. The results demonstrated that 0.03 and 0.06 % EFF treatments reduced mycelial growth of Botrytis cinerea by 41 and 89 %, respectively. The lesion diameter of the 0.03 and 0.06 % EFF-treated fruit was 28 and 76 % smaller than the control. Furthermore, EFF-treated fruit exhibited significantly higher activities of defense-related enzymes compared to the control, with total phenolic content increasing by 1.2 and 1.3-fold for the 0.03 and 0.06 % treatments, respectively. These findings provide compelling evidence regarding the efficacy of EFF in suppressing Botrytis cinerea and highlight the role of defense-related enzymes in enhancing the fruit's resistance to decay. Overall, the study underscores the potential of EFF as a valuable and practical method for controlling fungal decay in kiwifruit during postharvest storage. • Hexanal-containing formulation reduced symptoms of fungal infection in kiwifruit. • Enhanced freshness formulation inhibited fungal growth of Botrytis cinerea. • EFF dip treatment contributed to the tolerance against B. cinerea in kiwifruit. • EFF-treated fruit had higher phenolic contents and activities of defence enzymes.