Oligogalacturonides Enhance Resistance against Aphids through Pattern-Triggered Immunity and Activation of Salicylic Acid Signaling.

The remarkable capacity of the generalist aphid to resist most classes of pesticides, along with the environmental and human health risks associated with these agrochemicals, has necessitated the development of safer and greener solutions to control this agricultural pest. Oligogalacturonides (OGs) are pectin-derived molecules that can be isolated from fruit industry waste. OGs have been shown to efficiently stimulate plant defenses against pathogens such as and . However, whether OGs confer resistance against phytophagous insects such as aphids remains unknown. Here, we treated plants with OGs and recorded their effects on the feeding performance and population of aphids. We also identified the defense mechanism triggered by OGs in plants through the analysis of gene expression and histological approaches. We found that OG treatments increased their resistance to infestation by reducing the offspring number and feeding performance. Furthermore, this enhanced resistance was related to a substantial accumulation of callose and reactive oxygen species and activation of the salicylic acid signaling pathway.