| Kiwifruit is subjected to postharvest fungal decay, resulting in significant economic losses during transport and storage. Chemical methods have been mainly employed on kiwifruit to extend shelf life. Increasing concerns about fungicide residues and food safety, however, have created great interest in exploring and developing alternative strategies for the management of postharvest diseases.In this study, the effect of hot water treatment (HWT) is investigated on fruit quality, disease incidence, physiological and biochemical characteristics in kiwifruit stored at 25 ℃ and 4 ℃; The pathogens on infected kiwifruit are isolated and identified. Then, the effect of HWT on germination and physiological and biochemical characteristics of the pathogen spores is evaluated; After 24 h of B. cinerea infection, we utilize an iTRAQ-based quantitative proteomic analysis to study the resposne of kiwifruit to B. cinerea. The main findings are as follows:(1) HWT (45 ℃ for 10 min) has no effect on soluble solids, titratable acid, hardness in kiwi fruit, but significantly reduces the natural disease incidence, and improves the activity of catalase, peroxidase and the content of total phenol in kiwifruit stored at 4 ℃ and 25 ℃. HWT triggeres defense system, and improves disease resistance in kiwifruit.(2) HWT effectively inhibites spore germination and germ tube elongation of B. cinerea and P. expansum. Reactive oxygen species (ROS) accumulation and protein impairment in the fungi triggered by HWT contribute to the inhibitory effect. Results of in vivo studies show that HWT effectively controls gray and blue mold in kiwifruit stored at 4 and 25 ℃. HWT damages the pathogen, inhibites spore germination and growth, and reduces the pathogenic ability.(3)The iTRAQ-based quantitative proteomic analysis of kiwifruit in response to B. cinerea infection and water infection as a control group has been conducted. The main differentially expressed proteins involves in basic metabolism, immune response, stress response, transcriptional regulation, regulation of enzyme activity, cytoskeleton, antioxidant response, etc. A total of 227 up-regulated proteins and 101 down-regulated proteins are identified. Most of the proteins are associated with disease resistance, such as peroxidase, chitinase, antifungal proteins, the synthesis of mitochondrial enzymes, heat shock proteins, and transcription factor.These findings indicate that the inhibition of postharvest decay in kiwifruit by HWT is associated with the inhibition of fungal spore germination and the elicitation of defense response in the kiwifruit host. Moreover, HWT used in this study doesn’t impair fruit quality. HWT appeares to represent a potential nonchemical alternative for the effective management of postharvest decay of kiwifruit. The mechanism of gray mold pathogenesis in kiwifruit is associated with peroxidase, chitinase, antifungal proteins, the synthesis of mitochondrial enzymes, heat shock proteins, and transcription factor. |
