Effects of Methyl Salicylate on Host Plant Acceptance and Feeding by the Aphid Rhopalosiphum padi

Abstract

Methyl salicylate (MeSA) is a volatile shown to act as an inducer of plant defense against pathogens and certain herbivores, particularly aphids. It has been shown to have potential for aphid pest management, but knowledge on its mode of action is lacking, particularly induced plant-mediated effects. This study investigated the effects of exposing plants to MeSA on the host searching, host acceptance and feeding behavior of the bird cherry-oat aphid Rhopalosiphum padi. Barley plants were exposed to volatile MeSA for 24 h, after which biological effects were tested immediately after the exposure (Day 0), and then 1, 3 and 5 days after the end of the exposure. Aphid settling on MeSA-exposed plants was significantly reduced on days 0, 1 and 3, but not on day 5. In olfactometer tests, aphids preferred the odor of unexposed plants on days 1 and 3, but not on day 0 or 5. Analysis of volatiles from exposed and unexposed plants showed higher levels of MeSA from exposed plants, most likely absorbed and re-released from plant surfaces, but also specific changes in other plant volatiles on days 0, 1 and 3. High doses of MeSA did not affect aphid orientation in an olfactometer, but lower doses were repellent. Analysis of aphid feeding by Electronic penetration graph (EPG) showed that MeSA exposure resulted in resistance factors in barley plants, including surface factors and induced systemic factors in other tissues including the phloem. The results support the potential of MeSA as a potential tool for management of aphid pests.

Volatile interactions between specific undamaged barley cultivars affect aphid feeding behavior and performance

“…However, the importance of the increased number of potential drops in plant resistance against aphids is still unknown (Sun et al 2018). Volatiles from damaged plants, such as methyl salicylate, induce effects on the leaf surface resistance factor, prolonging the time until the first probe on exposed, compared to unexposed, barley plants (Ninkovic et al 2021). The recent review paper suggested that volatile cues can induce early responses by changing the receiving plant surface (Brosset and Blande 2022).…”

Floral constituents of the Australian tar tree,

“…For example, barley exposed to deuterated methyl salicylate showed significant qualitative and quantitative changes in the chemical profile of the headspace. [51] Methyl salicylate is also known as a mobile signal to induce systemic acquired resistance against biotrophic pathogens in the tobacco plant. [52] Ethyl and methyl salicylates are the major aromatic constituents in solvent extracts of the tar tree flowers, while phenylpropanoids and phenylbutanoids are present only in minute amounts.…”

Exogenous Application of a Plant Elicitor Induces Volatile Emission in Wheat and Enhances the Attraction of an Aphid Parasitoid Aphidius gifuensis

“…GC-MS results showed that the volatile compounds and the release amount reached the maximum at 24 h after treated with 1 mmol/L and 0.5 mmol/L MeSA, and decreased gradually at 48 h and 72 h. However, D-limonene and MeSA emissions dramatically increased at 72 h. This may have opened up the de novo synthesis pathway of MeSA. This pathway could be opened after wheat was treated with MeSA and the release amount of MeSA was gradually increased [31].…”