Induction of fresh produce defense response: Mechanism, challenges, and future directions

Induced resistance is a relatively novel and effective approach for managing postharvest disease. Fresh fruit and vegetables are highly susceptible to biotic and abiotic stresses, such as fungal pathogens and suboptimal temperatures, which lead to substantial postharvest losses and reduced shelf life. Once detached, fruit and vegetables continue ripening and senescence, which weakens the tissues, making them vulnerable to pathogens. Physical, chemical, and biological treatments could trigger the innate immune response of fruit and vegetables, which could reduce postharvest loss. This review aims to elucidate the mechanisms underlying the induction of defense responses in fresh produce. Chemical, biological, or physical inducers activate the fresh produce defense pathways, synthesizing defense-related proteins and metabolites, thus stimulating the plant's natural defense against pathogens and environmental stresses. Those inducers often trigger signaling cascades involving phytohormones, reactive oxygen species (ROS), and signals, orchestrating a complex network of molecular defensive combat fields. While there is progress in the induced resistance field, future challenges remain. These challenges include acquiring more knowledge of the specific defense pathways in different agricultural produce and their potential impact on produce quality and tolerance. Moreover, the inducer should be effective, economical, and safe. Adapting advanced technologies, such as omics approaches and biotechnological tools, holds the potential for the precise modulation of defense responses, leading to the development of tailored strategies for different produce types and specific biotic and abiotic stress.