Volatile organic compound emissions induced by the aphid Myzus persicae differ among resistant and susceptible peach cultivars and a wild relative

Abstract

Little is known on aphid-induced emissions of volatile organic compounds (VOCs) from trees and particularly on their intraspecific variability in association with resistance traits. We compared VOC emissions from five peach cultivars (Prunus persica (L.) Batsch) and a wild relative (Prunus davidiana (Carrière) Franch) that differ in their level (susceptible/resistant) and type (antixenosis, antibiosis) of resistance to the green peach aphid, Myzus persicae (Sulzer). Additionally, the kinetics of VOC induction in response to aphids was compared with that by mechanical wounding. Qualitative and overall quantitative differences among peach genotypes were found in VOC emissions that were mainly composed of methyl-salicylate, farnesenes, (E)-β-ocimene and (E)-4,8-dimethyl-1,3,7-nonatriene. Irrespective of the type of resistance, all resistant genotypes had increased VOC emissions upon aphid attack, while in susceptible genotypes emissions remained low. Emission increases were highest in the genotypes that express increased aphid resistance during second infestations, which had also the highest proportions of methyl-salicylate in their emissions. VOC induction by aphids proceeded slowly with a delay of several hours. Artificial wounding of leaves did not result in emissions of aphid-induced VOCs but caused an immediate burst of green leaf volatiles and benzaldehyde. We conclude that VOC induction in resistant peach cultivars is part of a general defence syndrome that is being avoided or suppressed by M. persicae in the susceptible genotypes. The induction likely involves an aphid-specific elicitor and (methyl)-salicylate in the subsequent signalling and regulation processes that should include gene activation due to the marked delay in the emission response. The results are compared with those of the literature and discussed in view of their ecological and environmental significance.

Quantitative patterns between plant volatile emissions induced by biotic stresses and the degree of damage

“…Terpenoid emissions in Z. mays elicited by oral secretion of Spodoptera littoralis increased with decreasing soil water availability (Gouinguené and Turlings, 2002), and increased curvilinearly with air humidity, light intensity, and temperature (Gouinguené and Turlings, 2002). These environmental responses are analogous to observations in other species (Staudt and Lhoutellier, 2007; Staudt et al, 2010; Staudt and Lhoutellier, 2011), and are consistent with the strong connection of the production of induced terpenoid volatiles and photosynthetic carbon metabolism (see above). In addition, due to high water-solubility of some of the induced compounds such as linalool, methanol and LOX pathway volatiles, variations in stomatal openness during the day and in response to soil drought can directly affect the emissions of water-soluble volatiles (Niinemets et al, 2002; Niinemets et al, 2004; Harley et al, 2007; Harley, 2013).…”

Disentangling olfactory and visual information used by field foraging birds

“…MeSA is an aromatic compound naturally produced by plants under attack from phloem-feeding herbivores like aphids (Staudt et al, 2010). The role of MeSA in plant-plant and plant-insect interactions has been demonstrated in cereal plant species (Ninkovic et al, 2003) as well as other plant systems (James, 2005;Orre, Wratten, Jonsson, & Hale, 2010;Snoeren et al, 2010;Tang, Zhao, & Gao, 2013).…”

Monoterpene and sesquiterpene emissions from <i>Quercus coccifera</i> exhibit interacting responses to light and temperature

“…Other sources of emission variation such as the stress dose dependent induction kinetics (e.g. Copolovici et al, 2011;Staudt et al, 2010) or endogenous circadian clocks (e.g. Kunert et al, 2002) come into play and thus veil possible short-term light and temperature effects on emissions.…”