title: The primary module in Norway spruce defence signalling against H. annosum s.l. seems to be jasmonate-mediated signalling without antagonism of salicylate-mediated signalling.
abstract: A key tree species for the forest industry in Europe is Norway spruce [Picea abies (L.) Karst.]. One of its major diseases is stem and butt rot caused by Heterobasidion parviporum (Fr.) Niemelä & Korhonen, which causes extensive revenue losses every year. In this study, we investigated the parallel induction of Norway spruce genes presumably associated with salicylic acid- and jasmonic acid/ethylene-mediated signalling pathways previously observed in response to H. parviporum. Relative gene expression levels in bark samples of genes involved in the salicylic acid- and jasmonic acid/ethylene-mediated signalling pathways after wounding and inoculation with either the saprotrophic biocontrol fungus Phlebiopsis gigantea or with H. parviporum were analysed with quantitative PCR at the site of the wound and at two distal locations from the wound/inoculation site to evaluate their roles in the induced defence response to H. parviporum in Norway spruce. Treatment of Norway spruce seedlings with methylsalicylate, methyljasmonate and inhibitors of the jasmonic acid/ethylene signalling pathway, as well as the Phenylalanine ammonia lyase inhibitor 2-aminoindan-2-phosphonic acid were conducted to determine the responsiveness of genes characteristic of the different pathways to different hormonal stimuli. The data suggest that jasmonic acid-mediated signalling plays a central role in the induction of the genes analysed in this study irrespective of their responsiveness to salicylic acid. This may suggest that jasmonic acid-mediated signalling is the prioritized module in the Norway spruce defence signalling network against H. parviporum and that there seems to be no immediate antagonism between the modules in this interaction.
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: Jenny
authors.initials: J
authors.lastname: Arnerup
authors.forename: Miguel
authors.initials: M
authors.lastname: Nemesio-Gorriz
authors.forename: Karl
authors.initials: K
authors.lastname: Lundén
authors.forename: Frederick O
authors.initials: FO
authors.lastname: Asiegbu
authors.forename: Jan
authors.initials: J
authors.lastname: Stenlid
authors.forename: Malin
authors.initials: M
authors.lastname: Elfstrand
mesh_terms: D001487:Basidiomycota / Q000502:physiology*; D003517:Cyclopentanes / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D054884:Host-Pathogen Interactions; D007189:Indans; D063065:Organophosphonates; D054883:Oxylipins / Q000378:metabolism*; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D028222:Picea / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D024301:Plant Bark / Q000378:metabolism; D010935:Plant Diseases; D012459:Salicylates / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: C411146:2-aminoindan-2-phosphonic acid; D003517:Cyclopentanes; D005030:Ethylenes; D007189:Indans; D063065:Organophosphonates; D054883:Oxylipins; D012459:Salicylates; C011006:jasmonic acid; C036216:ethylene; D010650:Phenylalanine Ammonia-Lyase