Variation in Herbivory-induced Volatiles Among Cucumber (Cucumis sativus L.) Varieties has Consequences for the Attraction of Carnivorous Natural Enemies

Abstract

In response to herbivory by arthropods, plants emit herbivory-induced volatiles that attract carnivorous enemies of the inducing herbivores. Here, we compared the attractiveness of eight cucumber varieties (Cucumis sativus L.) to Phytoseiulus persimilis predatory mites after infestation of the plants with herbivorous spider mites (Tetranychus urticae) under greenhouse conditions. Attractiveness differed considerably, with the most attractive variety attracting twice as many predators as the least attractive variety. Chemical analysis of the volatiles released by the infested plants revealed significant differences among varieties, both in quantity and quality of the emitted blends. Comparison of the attractiveness of the varieties with the amounts of volatiles emitted indicated that the quality (composition) of the blend is more important for attraction than the amount of volatiles emitted. The amount of (E)-β-ocimene, (E,E)-TMTT, and two other, yet unidentified compounds correlated positively with the attraction of predatory mites. Quantities of four compounds negatively correlated with carnivore attraction, among them methyl salicylate, which is known to attract the predatory mite P. persimilis. The emission of methyl salicylate correlated with an unknown compound that had a negative correlation with carnivore attraction and hence could be masking the attractiveness of methyl salicylate. The results imply that the foraging success of natural enemies of pests can be enhanced by breeding for crop varieties that release specific volatiles.Electronic supplementary materialThe online version of this article (doi:10.1007/s10886-011-9906-7) contains supplementary material, which is available to authorized users.

Integrative Analyses of Nontargeted Volatile Profiling and Transcriptome Data Provide Molecular Insight into VOC Diversity in Cucumber Plants (Cucumis sativus)

“…Several cDNA contigs were identified as candidate sequences for volatile production based on high Pearson correlation coefficient (PCC) values between volatile emission data and gene expression data. Cucumber (E,E)-a-farnesene synthase and (E)-b-caryophyllene synthase were functionally characterized in vitro (Mercke et al, 2004).A recent study demonstrated that the volatile emission levels from infested cucumber leaves, including (E)-b-ocimene, (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene, and two other unknown compounds, correlated positively with the attraction of Phytoseiulus persimilis, a predatory mite species that targets herbivorous spider mites (Kappers et al, 2011). This result suggested that the VOCs can protect cucumber plants indirectly.…”

Comparative Study of the Volatiles’ Composition of Healthy and Larvae-Infested Artemisia ordosica

“…Releasing these volatile compounds can improve plants' resistance to attacking herbivores, and an important aspect of defence is the ability to attract the herbivore's natural enemies such as predators and parasitoids (Mumm et al, 2008;Zakir, 2011;Kappers et al, 2011). Many herbivore-induced volatiles are terpenoids, the largest class of natural products (Dicke et al, 1990;Turlings et al, 1990;Dicke, 1994;Takabayashi et al, 1994).…”

“…The procedure was similar to that described by Kappers et al (2011). Each aerial part was covered with an oven bag (48.26 cm x 23 cm x 1.27 cm; Reynolds, Richmond, CA, USA).…”

Compostos orgânicos voláteis na defesa induzida das plantas contra insetos herbívoros

“…16 Os voláteis induzidos após o ataque dos herbívoros apresentam grande variabilidade e dependem da espécie de planta, 24 do herbívoro 25 e do seu instar ou estadio. 26 Também variam com o genótipo 27 e, neste caso, entre partes da planta e de acordo com o tempo, 28 considerado pelo período de 24 horas, uma vez que as emissões destes variam de dia e noite. 29 Isto facilita a mediação de interações da planta com insetos diurnos e noturnos.…”