Effects of methyl jasmonate on chemical defenses of conifer seedlings in relation to feeding by Hylobius abietis

The chemical elicitor methyl jasmonate (MeJA) could replace insecticides in Europe and Asia for protection of young conifers against the pine weevil (Hylobius abietis). This thesis mainly focuses on the effects of MeJA treatment on chemical defenses of conifers from seedling batches with documented field resistance. Tissues of three pine species and one spruce species, with various treatments, were here extracted in hexane, whereafter volatile contents of tissues were separated and analyzed by 2D GC-MS. Induced responses of seedlings of Maritime pine (Pinus pinaster) and Monterey pine (Pinus radiata) to the folivore pine processionary (Thaumetopoea pityocampa), and the phloem-feeder H. abietis, have been studied. Amounts of mono- and sesqui-terpenes (and also non-volatile resin) in conifer tissues (needles and phloem) were less induced by T. pityocampa than by H. abietis. The MeJA-treated seedlings of Scots pine (Pinus sylvestris) changed their composition of phloem monoterpenes (induction of (-)-β-pinene), and were better protected in field than the seedlings of Norway spruce (Picea abies), which increased their total amounts of monoterpenes. Orientation bioassays with H. abietis showed deterrent effects of (-)-β-pinene, (+)-3-carene, (-)-bornyl acetate and 1,8-cineole. Conversely, (-)-α-pinene (induced in P. abies but not in P. sylvestris) was non-deterrent. MeJA-treated seedlings fed on by H. abietis contained higher amounts of the H. abietis antifeedant 2-phenylethanol, in tissues and emissions. Phloem of control seedlings instead induced the (+)-α-pinene, which is one of the enantiomers of the H. abietis attractant α-pinene. In response to MeJA treatment, the relative amounts of the (+)-α-pinene increased in the phloem of  P. radiata, while it decreased in P. pinaster phloem. The preference of H. abietis in the field for P. radiata before P. pinaster may be explained by these changes in enantiomers of the H. abietis attractant α-pinene.Barrträd är viktiga för skogsindustrin. I Sverige består 57% av ytan av produktiv skogsmark, och av dessa träd utgörs 80% av gran och tall. Som försvar mot insekter och sjukdomar, producerar barrträden kådämnen. För unga barrträd i Europa och Asien är snytbaggen (Hylobius abietis) en allvarlig skadegörare, som orsakar skogsnäringen stora kostnader. För att skydda små gran- och tallplantor före utplanteringen, skulle växthormonet metyljasmonat (MeJA) kunna användas. I denna avhandling har effekter av MeJA-behandling och insektsangrepp undersökts på de två viktigaste barrträden i Sverige, tall och gran (Pinus sylvestris och Picea abies) och på två arter i medelhavsområdet (Pinus radiata och Pinus pinaster). De kemiska försvarsämnena i barrträd har analyserats för att utvärdera effekterna av MeJA-behandling. Vävnader från barrträd med olika behandling har extraherats i organiska lösningsmedel och dofterna från plantorna har insamlats genom fastfas-mikroextraktion. De flyktiga ämnena har separerats och identifierats med hjälp av gaskromatografi och masspektrometri (GC-MS). Dessutom har optiskt aktiva doftämnen separerats med hjälp av en tvådimensionell GC-MS. Plantornas olika försvarsreaktioner har studerats vid angrepp av snytbaggen, som är en floemätare, och av tallfjärilslarv (Thaumetopoea pityocampa), som huvudsakligen äter barr. De lättflyktiga ämnena (mono- och seskviterpener) och de icke-flyktiga ämnena (kådsyror) ökade mer i stam och barr från angrepp av H. abietis än av T. pityocampa. Sammansättning av monoterpener ändrades i de MeJA-behandlade tallplantorna i Sverige, specifikt ökade (-)-β-pinene i stamfloemet. Tallplantorna var bättre skyddade i fält än granplantorna, där den totala mängden monoterpener ökade. (-)-β-Pinene, (+)-3-carene, (-)-bornyl acetate och 1,8-cineole visade sig ha en negativ effekt på snytbaggens orientering mot talldoft i orienteringstester. En av monoterpenerna, (-)-α-pinene, som av MeJA-behandlingen inducerats i granen, men inte i tallen, hade ingen negativ effekt på snytbaggen. MeJA-behandlade tallplantor som angripits av snytbaggen, innehöll större mängder av snytbagge-äthämmaren 2-fenyletanol, både i vävnader och i emissioner. Stam från kontrollplantor inducerade istället (+)-α-pinene, vilken är en av de optiska isomererna av snytbagge-attrahenten α-pinene. För de spanska arterna, som svar på MeJA-behandling, ökade de lättflyktigaste terpenerna i barren hos P. radiata men inte hos P. pinaster, vilken redan innehöll en hög terpenhalt. De relativa mängderna av (+)-α-pinene ökade också i stammen hos P. radiata, medan de minskade i P. pinaster. I fält väljer snytbaggen att gå till P. radiata- framför P. pinaster-plantor, vilket kan vara kopplat till de skillnader i α-pinene-isomerer, vilka här har observerats.QC 20160304</p

Kvinnors upplevelser under cytostatikabehandling vid bröstcancer

Bakgrund: Bröstcancer är den vanligaste cancerformen kvinnor diagnostiseras av världen över. Cytostatikabehandling är en frekvent metod som används vid bröstcancer och bidrar till en mängd olika biverkningar. När kvinnan går från frisk till sjuk sker en transition, vilket innebär förändringar i livet. Syfte: Att beskriva kvinnors upplevelser av sin vardag under cytostatikabehandlingen vid bröstcancer.Metod:En litteraturöversikt med kvalitativ design. Sexton artiklar söktes fram i databaserna CINAHL, MEDLINE och PsycINFO. En modell av Friberg i fem steg användes i analysen. Resultat: Upplevelsen av cytostatikabehandlingen gav kvinnorna en förändrad bild av sin vardag. De upplevde att vardagen blev påverkad när kroppen förändrades och de fick olika känslor när biverkningarna kom. Kvinnorna fick existentiella tankar kring livslust och döden.  Yttre faktorer som familjestöd, stöd från sjuksköterskan, arbetsrelaterade upplevelser samt hur kvinnan upplever sin vardag vid fysisk aktivitet under cytostatikabehandlingen var fynd som framkom. Slutsats: Cytostatikabehandlingen bidrog till att kvinnorna upplevde en känsla av förlorad identitet likväl ett nytt synsätt på livet. Familj och vänner hade en betydelsefull roll under behandlingsperioden. Sammanfattningsvis uttrycks transitionen varierande beroende på kvinnans förutsättningar.

Effects of methyl jasmonate on the concentration of volatile terpenes in tissues of Maritime pine and Monterey pine and its relation to pine weevil feeding

QC 20181009</p

Inducibility of chemical defences by two chewing insect herbivores in pine trees is specific to targeted plant tissue, particular herbivore and defensive trait

There is increasing evidence that plants can react to biotic aggressions with highly specific responses. However, few studies have attempted to jointly investigate whether the induction of plant defences is specific to a targeted plant tissue, plant species, herbivore identity, and defensive trait. Here we studied those factors contributing to the specificity of induced defensive responses in two economically impor- tant pine species against two chewing insect pest herbivores. Juvenile trees of Pinus pinaster andP. radiata were exposed to herbivory by two major pest threats, the large pine weevil Hylobius abietis (a bark-fee- der) and the pine processionary caterpillar Thaumetopoea pityocampa (a folivore). We quantified in two tissues (stem and needles) the constitutive (control plants) and herbivore-induced concentrations of total polyphenolics, volatile and non-volatile resin, as well as the profile of mono- and sesquiterpenes. Stem chewing by the pine weevil increased concentrations of non-volatile resin, volatile monoterpenes, and (marginally) polyphenolics in stem tissues. Weevil feeding also increased the concentration of non-vol- atile resin and decreased polyphenolics in the needle tissues. Folivory by the caterpillar had no major effects on needle defensive chemistry, but a strong increase in the concentration of polyphenolics in the stem. Interestingly, we found similar patterns for all these above-reported effects in both pine spe- cies. These results offer convincing evidence that induced defences are highly specific and may vary depending on the targeted plant tissue, the insect herbivore causing the damage and the considered defensive compound.Peer reviewe

Variation in Methyl Jasmonate-Induced Defense Among Norway Spruce Clones and Trade-Offs in Resistance Against a Fungal and an Insect Pest

An essential component of plant defense is the change that occurs from a constitutive to an induced state following damage or infection. Exogenous application of the plant hormone methyl jasmonate (MeJA) has shown great potential to be used as a defense inducer prior to pest exposure, and could be used as a plant protection measure. Here, we examined (1) the importance of MeJA-mediated induction for Norway spruce (Picea abies) resistance against damage by the pine weevil Hylobius abietis, which poses a threat to seedling survival, and infection by the spruce bark beetle-associated blue-stain fungus Endoconidiophora polonica, (2) genotypic variation in MeJA-induced defense (terpene chemistry), and (3) correlations among resistance to each pest. In a semi-field experiment, we exposed rooted-cuttings from nine different Norway spruce clones to insect damage and fungal infection separately. Plants were treated with 0, 25, or 50 mM MeJA, and planted in blocks where only pine weevils were released, or in a separate block in which plants were fungus-inoculated or not (control group). As measures of resistance, stem area debarked and fungal lesion lengths were assessed, and as a measure of defensive capacity, terpene chemistry was examined. We found that MeJA treatment increased resistance to H. abietis and E. polonica, but effects varied with clone. Norway spruce clones that exhibited high constitutive resistance did not show large changes in area debarked or lesion length when MeJA-treated, and vice versa. Moreover, insect damage negatively correlated with fungal infection. Clones receiving little pine weevil damage experienced larger lesion lengths, and vice versa, both in the constitutive and induced states. Changes in absolute terpene concentrations occurred with MeJA treatment (but not on proportional terpene concentrations), however, variation in chemistry was mostly explained by differences between clones. We conclude that MeJA can enhance protection against H. abietis and E. polonica, but the extent of protection will depend on the importance of constitutive and induced resistance for the Norway spruce clone in question. Trade-offs among resistances do not necessarily hinder the use of MeJA, as clones that are constitutively more resistant to either pest, should show greater MeJA-induced resistance against the other.

Resin acids as inducible chemical defences of pine seedlings against chewing insects.

Inducibility of defences in response to biotic stimuli is considered an important trait in plant resistance. In conifers, previous research has mostly focused on the inducibility of the volatile fraction of the oleoresin (mono- and sesquiterpenes), leaving the inducibility of the non-volatile resin acids largely unexplored, particularly in response to real herbivory. Here we investigated the differences in the inducibility of resin acids in two pine species, one native from Europe (Pinus pinaster Ait.) and another from North America (Pinus radiata D. Don), in response to wounding by two European insects: a bark chewer, the pine weevil (Hylobius abietis L.), and a defoliator, the pine processionary caterpillar (Thaumetopoea pityocampa Schiff.). We quantified the constitutive (control) and induced concentrations of resin acids in the stem and needles of both pine species by gas chromatography techniques. Both pine species strongly increased the concentration of resin acids in the stem after pine weevil feeding, although the response was greater in P. pinaster than in P. radiata. However, systemic defensive responses in the needles were negligible in both pine species after pine weevil feeding in the stem. On the other hand, P. radiata locally reduced the resin acid concentration in the needles after pine caterpillar feeding, whereas in P. pinaster resin acid concentration was apparently unaffected. Nevertheless, systemic induction of resin acids was only observed in the stem of P. pinaster in response to pine caterpillar feeding. In summary, pine induced responses were found highly compartmentalized, and specific to herbivore identity. Particularly, plant defence suppression mechanisms by the pine caterpillar, and ontogenetic factors might be potentially affecting the induced response of resin acids in both pine species

Improved forest regeneration by triggering the induced defense of conifer seedlings against bark-feeding insects

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.Peer reviewe

Diterpene-based induced defences in pine trees in response to a bark chewing weevil and a folivorous caterpillar

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.Peer reviewe

Cambios en metabolitos secundarios de pinos en respuesta a la larva de procesionaria del pino y el gran gorgojo del pino

Comunicación presentada en la Reunión celebrada en la ETSI Montes, Forestal y del Medio Natural de la Universidad Politécnica de Madrid, el día 8 de octubre de 2015.Pine trees are long -lived, widespread organisms that have to cope with multiple biotic stresses during their life cycle. To face against biological aggressions pine trees harbour terpenoids and phenolics as major chemical defences that may avoid or deter the attack providing resistance. Mono and sesquiterpenes, the volatile fraction of oleoresin, have been found to be adaptive resistance traits and to differ between and within species. However much less attention has been paid to sources of phenotypic variation in diterpenes, the non- volatile fraction of oleoresin that seals the stem wounds after oxidization. We examined the induced defensive responses of the diterpene fraction in two pine species, one native (Maritime pine) and one exotic (Monterey pine) to Europe, against two native insect herbivores, the bark chewing pine weevil and the pine processionary caterpillar; and explored the association between the induced chemical profile of diterpenes in each species and the subsequent damage. We found that the two pine species showed different constitutive and induced diterpene concentration in stem and needles. Whereas Pinus pinaster increased total di terpene concentration only in the stem against the two herbivores, P. radiata diterpene defences were locally induced in the damaged tissue due to herbivore feeding activity. Regarding to the chemical diterpene profile, the native P. pinaster produced a ge neral induced response increasing diterpene concentration against the two herbivores in the stem, whereas the exotic P. radiata showed a weevil -induced increase and a caterpillar -induced decrease in the most abundant diterpenes in the needles.Peer reviewe