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The effect of magnetic field (MF) on the postharvest quality and energy metabolism of green chili was investigated. An MF of 4 mT intensity was applied during the refrigeration of green chili pepper. Conventional refrigeration (CR) was used as a control, and the chili pepper fruit was stored at 10 °C and sampled at 1, 5, 10, 20, and 30 d after harvest. The results showed that MF inhibited the senescence of chili pepper and quality deterioration, as evidenced by higher water content, vitamin C (VC) and flesh firmness as well as lower weight loss and decay incidence. The decrease of hue angle values and the chlorophyll content were remarkably depressed by MF treatment, indicating an efficient delay in the yellowing of chili pepper. In terms of metabolism, MF sustained high adenosine triphosphate (ATP) content, energy charge (EC), and activities of key enzymes engaged in energy metabolism (H+-ATPase, Ca2+-ATPase, succinate dehydrogenase, and cytochrome C oxidase). Additionally, there was an increase in the concentration of major energy metabolites, including citric-acid, isocitric-acid, D-Glucose-6-phosphate, and D-Fructose-6-phosphate. These results suggested that MF may be used as a promising strategy for preventing the decay of postharvest green chilies and prolonging their shelf life. [Display omitted] • MF slowed down senescence and quality deterioration of green chilies. • MF inhibited the loss of chlorophyll and VC content. • MF sustained ATP, EC, and key enzyme activities for energy metabolism. • Major energy metabolites were maintained at high level by MF. [ABSTRACT FROM AUTHOR]

The widespread use of synthetic fungicides has gradually increased drug resistance and has negatively impacted human health and caused environmental contamination. This study aimed to investigate the effects and mechanisms of action of protocatechuic acid methyl ester (PCAME), a plant-derived biologically active compound, against decay mold disease of postharvest strawberry fruit caused by Botrytis cinerea. PCAME inhibited in vitro mycelial growth and spore germination of B. cinerea and decreased the susceptibility of strawberries to B. cinerea invasion, as revealed by the lesion area. PCAME effectively altered the transcriptional profile of B. cinerea and enhanced the transcription of genes related to oxidative stress and cell membrane lipid peroxidation, ultimately causing membrane disturbance and cell death. These results were verified by increased extracellular conductivity, leakage of cytoplasmic constituents including sugars and nucleotides, and propidium iodide staining. Furthermore, PCAME treatment activated the expression of genes involved in antioxidant metabolism and defense-related proteins in strawberries infected with B. cinerea. These data suggest that PCAME inhibits postharvest gray mold disease in strawberries through direct antifungal activity and the enhancement of host resistance responses. PCAME can be considered as natural agent that alleviates postharvest gray mold decay in strawberries. [Display omitted] • PCAME exhibited in vitro and in vivo antifungal activity against B. cinerea. • PCAME disturbed the integrity of cell membrane of B. cinerea. • PCAME caused oxidative stress and membrane lipid peroxidation of B. cinerea. • PCAME induced resistance responses of strawberries. [ABSTRACT FROM AUTHOR]