Eliciting sweet pepper plant resistance to Aulacorthum solani and attractiveness on Aphelinus abdominalis by exposure to (Z)-3-hexenyl propanoate

It is widely documented that plants respond to herbivory by releasing volatile compounds mediated by phytohormone signaling pathways. Herbivore-Induced Plant Volatiles (HIPVs), among which are the green leaf volatiles, can repel herbivores, attract their natural enemies, and warn neighboring plants of herbivore attacks. Plants that receive these warning signals activate defense mechanisms and therefore become more resistant to pests and diseases. In this work, we tested whether plants activated by exposure to the green leaf volatile (Z)-3-hexenyl propanoate [(Z)-3-HP)] can enhance the management of one of the most important pests of sweet peppers, the aphid Aulacorthum solani (Kalt.) (Homoptera: Aphididae). Here, we show that sweet pepper plants exposed to (Z)-3-HP induce plant defenses that repel A. solani winged adults and attract females of Aphelinus abdominalis (Dalman) (Hymenoptera: Aphelinidae), an aphid parasitoid used to control a plethora of aphid pests, including A. solani. Additionally, (Z)-3-HP-exposed plants were less infested by A. solani than their non-exposed counterparts under greenhouse conditions. Significant transcriptional differences were obtained when studying the temporal gene expression pattern of three defense-related genes, ASR1, PIN2, and AMP1, markers of abscisic acid, jasmonic acid, and salicylic acid, respectively, during the duration of the greenhouse experiment. Our results demonstrate how the use of volatiles as plant defense inducers can play a role in the management of A. solani in sweet pepper and opens the door to exploring this technique on other aphid pests in other crops.