Chlorogenic acid induces resistance against Penicillium expansum in peach fruit by activating the salicylic acid signaling pathway

The objective of this study was to investigate the effect of chlorogenic acid (CGA) treatment on induction of resistance against pathogens in peach fruit. Treatment with CGA at 25-150 mg L−1 was effective at reducing lesion diameter and decay index of peach fruit during storage at 25 °C after Penicillium expansum infection. CGA treatment had also significant beneficial effects on fruit quality parameters including firmness, soluble solids contents, pH value, and titratable acidity. Activities of main defense-related enzymes and expression of key genes involved in the salicylic acid (SA) signaling pathway, such as PAL, ICS, WRKY, NPR1, PR1, CHI, GLU, PR5, and POD, were enhanced by CGA treatment. These findings suggest that CGA treatment is a promising approach to controlling postharvest blue mold rot in peach fruit, and activation of the SA signaling pathway may play a potential role in mechanisms involving CGA-induced plant disease resistance.