Exogenous prohydrojasmon treatment improves potato resistance to specialist and generalist herbivores and enhances biological control

BACKGROUND: The increasing challenges of pesticide resistance and environmental harm highlight the need for innovative plant-based crop protection strategies. This study investigated the potential of prohydrojasmon (PDJ), a synthetic jasmonate derivative that is primarily used as a growth regulator, to enhance plant resistance against specialist (Phthorimaea operculella Z) and generalist (Thrips tabaci) herbivores in potato (Solanum tuberosum L.). RESULTS: We examined the effects of exogenous PDJs on plant growth, herbivore performance, insect host preferences, volatile organic compound (VOC) emissions and defense-related gene expression. Our results revealed that PDJ treatment reduced herbivore feeding damage, survival and oviposition in a dose-dependent manner without compromising plant growth or physiological parameters. Remarkably, PDJ treatment simultaneously enhanced the attraction and efficiency of P. operculella eggs parasitoid, Trichogramma chilonis ishii and thrips predator, Orius insidiosus Wolff. Substantial increases in defensive VOCs, particularly β-caryophyllene, copaene and 3-carene, were found upon PDJ treatment. Y-tube olfactometer assays confirmed that these VOCs effectively repelled herbivores while attracting their natural enemies. Furthermore, PDJ treatment strongly up-regulated the jasmonic acid biosynthesis genes (StAOS, StAOC) while down-regulating salicylic acid pathways genes (StEDS1, StNPR1). CONCLUSION: This study sheds light on the use of PDJ as a promising elicitor for integrated pest management, capable of enhancing direct and indirect herbivore defense mechanisms in potato without fitness costs, offering an environmentally sustainable approach to crop protection.