Metabolomic and Functional Evidence for Psoralen Associated with Resistance of Pepper against the Whitefly

<i>Bemisia tabaci</i> is a major global pest causing severe crop losses through phloem feeding and virus transmission, with heavy insecticide use driving resistance. Pepper (<i>C. annuum</i>) is naturally resistant to the MEAM1 whitefly, offering a model for studying inducible plant defenses. Metabolomic analysis revealed that psoralen accumulates in pepper leaves after whitefly feeding, a secondary metabolite known for insecticidal properties. Bioassays showed that psoralen significantly reduces adult survival and oviposition. Biochemical assays further indicated that psoralen inhibits key whitefly detoxification enzymes (GSTs, CarEs) and digestive enzymes (cellulase, α-amylase). These findings identify psoralen as an inducible defense metabolite contributing to pepper resistance against <i>B. tabaci</i> and highlight its potential for sustainable whitefly control through crop improvement or botanical insecticide development.