Abstract

Pre-washed vegetables are gaining market share as upgraded consumption and faster lifestyles drive demand for convenience, safety, and health. However, pre-washing destroys the natural protective layer of fruit and vegetables, causing physical damage and water residue, which creates conditions for the reproduction of pathogens. Our research found that Verticillium dahliae -secreted Asp f2-like protein (VDAL) and VDAL interacted protein (VIP) addition during washing had a significant anti-pathogenic effect on pre-washed sweetpotatoes, reducing the decay rate from 50% to approximately 20% on day 24. Both VIP and VIP+VDAL treatments significantly inhibited the lesion expansion of Ceratocystis fimbriata in sweetpotatoes. Unlike traditional antipathogen methods, the VIP and VIP+VDAL did not directly kill pathogen but induced the host resistance of sweetpotatoes by rapidly activating the ROS burst while reducing the peak of H 2 O 2 and ·O 2 - simultaneously. The malondialdehyde content was lowered and the DPPH radical scavenging rate was increased in the later stage of storage. The VIP and VIP+VDAL treated sweetpotatoes possessed higher contents of polyphenol and flavonoid than control. And the activity of key enzyme for phenolic biosynthesis, phenylalanine ammonia-lyase, was enhanced as well. Compared with control, the activities of antioxidant enzymes including peroxidase, catalase and superoxide dismutase were increased in VIP and VIP+VDAL treated groups. Besides, the enhanced series of responses involved in ascorbate–glutathione non-enzymatic antioxidant cycle strengthened resistance to black spot pathogen, and delaying quality deterioration of sweetpotatoes. This study provided new insights for developing green and efficient strategies for controlling postharvest diseases in horticultural products.