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Póster presentado en Estocolmo (Suecia) entre el 29 de junio y el 3 de julio de 2015., Following an herbivore attack plants can reduce damage by inducing a wide variety of highly specific chemical and physical defences. Plants are able to recognize, integrate and respond accordingly in a specific manner to the biotic stimuli provoked by different herbivore species. This specificity of induced defences is particularly important for long-lived plants (e.g. pines) which have to face against multiple biological aggressions during their life cycle. In this sense, it has been recently documented that induction of mono- and sesquiterpenes (the volatile fraction of oleoresin) in pine trees is specific to plant species, herbivore identity and plant tissue. However, much less attention has been paid to understand the sources of phenotypic variation of diterpenes, the non-volatile fraction of oleoresin that seals the wounds after oxidization.

Trabajo presentado en Estocolmo (Suecia) entre el 29 de junio y el 3 de julio de 2015., Only in Sweden 360 million conifer seedlings are planted each year but a substantial proportion of these are killed by pine weevils (Hylobius abietis) and black spruce beetles (Hylastes cunicularius). A high survival rate is essential for a high primary production of forest raw materials and biomass. There is currently no suitable non-insecticide plant protection option for a large part of these seedlings. One option may, however, be to trigger the seedlings´ own induced defense by treating them with a plant activator at the nursery so that they are prepared when they later becomes attacked by pine weevils in the field. The induced defense is under natural conditions generally expressed after damage by, e.g. a pest insect, whereas constitutive defenses are permanently present. Constitutive defenses serves to inhibit an initial attack whereas the induced defense serves to actively and vigorously stop the attack. The induced defense is powerful but the time lag after an initial attack before the induced defenses are fully expressed may be detrimental for a plant when the pest pressure is high. This weakness of the induced defense can be circumvented by applying a plant activator to trigger the induced defense of the plant before it is exposed to attacks. There is a suitable plant activator to trigger the induced defense of conifers available. That is methyl jasmonate which is a substance that also is produced naturally when a plant is attacked. It triggers the production of traumatic resin channels and different types of chemical defense substances. In this talk I will present some recent results related to the potential of this method to protect conifer seedlings against pine weevils.

Póster presentado en Estocolmo (Suecia) entre el 29 de junio y el 3 de julio de 2015. Following an herbivore attack plants can reduce damage by inducing a wide variety of highly specific chemical and physical defences. Plants are able to recognize, integrate and respond accordingly in a specific manner to the biotic stimuli provoked by different herbivore species. This specificity of induced defences is particularly important for long-lived plants (e.g. pines) which have to face against multiple biological aggressions during their life cycle. In this sense, it has been recently documented that induction of mono- and sesquiterpenes (the volatile fraction of oleoresin) in pine trees is specific to plant species, herbivore identity and plant tissue. However, much less attention has been paid to understand the sources of phenotypic variation of diterpenes, the non-volatile fraction of oleoresin that seals the wounds after oxidization.

In my PhD work I analyze conifer constituents that seedlings produce and emit into the environment. The aim is to identify chemical resistance markers in Scots pine Pinus sylvestris against the large pine weevil Hylobius abietis. This insect is one of the economically most important forest pests in Sweden and almost 90% of the seedlings could die without protective measures such as shelterwood and soil scarification (1). Insecticides add to the protection of the seedlings but the future prohibition call for replacement. Aiming to explore the role of induced defences in pine resistance to this weevil we analyzed the chemical responses of pine seedlings to weevil damage and to the application of methyl jasmonate, a signal hormone that, exogenously applied, mimicks insect herbivory (2,3). Based on biological results from greenhouse trials in Sweden and in Spain, I evaluate stress responses from seedlings using GC-MS and LC-MS. From this I have found induction of ß-pinene in Scots pine (Pinus sylvestris) after pretreatment with methyl jasmonate, and in Maritime pine (P. pinaster) and Monterey pine (P. radiata) after pine weevil infestation. The induction is observed in both stem and needles. Further I investigate possible activation of the (-)-pinene-synthase using chiral analysis with 2D-GC-MS., The research is supported by the Swedish Foundation of Strategic Research