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Turlings, Ted

Nom
Turlings, Ted
Affiliation principale
Fonction
Professeur ordinaire
Email
ted.turlings@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/330

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  • Publication
    Métadonnées seulement
    Volicitin, an elicitor of maize volatiles in oral secretion of Spodoptera exigua: Isolation and bioactivity
    (2000)
    Turlings, Ted 
    ;
    Alborn, Hans
    ;
    Loughrin, John H
    ;
    Tumlinson, James H
    Plants respond to insect-inflicted injury by systemically releasing relatively large amounts of several volatile compounds, mostly terpenoids and indole. As a result, the plants become highly attractive to natural enemies of the herbivorous insects. In maize, this systemic response can be induced by the uptake via the stem of an elicitor present in the oral secretions of caterpillars. Such an elicitor was isolated from the regurgitant of Spodoptera exigua larvae, identified as N-(17-hydroxylinolenoyl)-L-glutamine, and named volicitin. Here we present details on the procedure that was used to isolate volicitin and the biosasays that demonstrate its potency as an elicitor of maize volatiles that attract parasitoids. With a series of liquid chromatography purification steps, volicitin was separated from all other inactive substances in the regurgitant of larvae of the noctuid moth S. exigua. Maize seedlings that were incubated in very low concentrations of pure natural volicitin released relatively large amounts of terpenoids and became highly attractive to the parasitoid Microplitis croceipes. The identification of this and other insect-derived elicitors should allow us to determine their precise source and function, and better understand the evolutionary history of the phenomenon of herbivore-induced volatile emissions in plants.
  • Publication
    Métadonnées seulement
    Herbivore-induced volatile emissions from cotton (Gossypium-hirsutum L) seedlings
    (1994)
    McCall, Philip J
    ;
    Turlings, Ted 
    ;
    Loughrin, John H
    ;
    Proveaux, Adron T
    ;
    Tumlinson, James H
    The effect of herbivory on the composition of the volatile blends released by cotton seedlings was investigated by collecting volatiles from undamaged, freshly damaged (0-2 hr after initiation of feeding), and old damaged (16-19 hr after initiation of feeding) plants on which com earworm caterpillars (Helicoverpa zea Boddie) were actively feeding. A blend of 22 compounds was consistently observed to be emitted by the old damaged plants with nine occurring either only in, or in significantly greater amounts in old damaged, as compared with freshly damaged plants. These were (Z)-3-hexenyl acetate, hexyl acetate, (E)-beta-ocimene, (3E)-4,8-dimethyl-1,3,7-nonatriene, (Z)-3-hexenyl butyrate, (E)-2-hexenyl butyrate, (Z)-3-hexenyl 2-methylbutyrate, (E)-2-hexenyl 2-methylbutyrate, and indole, The nature of this response is compared with other studies where herbivore-induced volatile responses are also known. The presence of large amounts of terpenes and aldehydes seen at the onset of feeding and the appearance of other compounds hours later suggest that cotton defense mechanisms may consist of a constitutive repertoire that is augmented by an induced mechanism mobilized in response to attack. A number of the induced compounds are common to many plants where, in addition to an immediate defensive function, they are known to be involved in the attraction of natural enemies.
  • Publication
    Métadonnées seulement
    Systemic release of chemical signals by herbivore-injured corn
    (1992)
    Turlings, Ted 
    ;
    Tumlinson, James H
    Corn seedlings respond to insect herbivore-inflicted injury by releasing relatively large amounts of several characteristic terpenoids and, as a result, become highly attractive to parasitic wasps that attack the herbivores. Chemical evidence showed that the induced emission of volatiles is not limited to the sites of damage but occurs throughout the plant. This evidence was obtained by comparing the release of volatiles from leaves of unharmed (control) seedlings with the release of volatiles from undamaged leaves of seedlings with two injured leaves treated with caterpillar regurgitant. Immediately after injury no differences were measured in the released volatiles, but several hours later the undamaged leaves of injured plants released the terpenoids linalool, (3E)-4,8-dimethyl-1,3,7-nonatriene, and (3E,7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene in significantly larger amounts than leaves of unharmed plants. Other volatiles that are released by herbivore-injured leaves were detected occasionally only in trace amounts from the undamaged leaves of a damaged seedling. The systemic release of volatiles by injured corn coincided with attractiveness to the parasitoid Cotesia margin-iventris; undamaged leaves of injured plants became significantly more attractive than leaves from control seedlings. These findings show conclusively that when a plant is injured by an insect herbivore the whole plant emits chemical signals.
  • Publication
    Métadonnées seulement
    Larval-damaged plants - source of volatile synomones that guide the parasitoid cotesia-marginiventris to the microhabitat of its hosts
    (1991)
    Turlings, Ted 
    ;
    Tumlinson, James H
    ;
    Eller, Fred J
    ;
    Lewis, W Joe
    Single and dual choice tests in a flight tunnel revealed that plants damaged by host larvae are the main source of the volatiles that attract females of the parasitoid Cotesia marginiventris (Cresson) to the microhabitat of its hosts. Frass and host larvae, the other two major components of a complete plant-host complex, were significantly less attractive than the damaged seedlings; frass alone was more attractive than larvae alone. However, a recombination of larvae with the damaged seedlings was significantly more attractive than the damaged leaves alone, or damaged leaves with frass. This was due to the additional feeding damage done by the larvae. The role of plants in the host-finding behaviour of parasitoids is discussed.