Lars Sandved Dalen
Senior Adviser
Abstract
Using decades of satellite observations, Finnish and Norwegian scientists calculated the warming effect caused by changes in the snow and ice cover of the Arctic and Antarctic regions.
Authors
Samuel Wilkinson Lars Sandved Dalen Thomas Olufsen Skrautvol Jurriaan Ton Paal Krokene Melissa MagerøyAbstract
Norway spruce (Picea abies) is an economically and ecologically important tree species that grows across northern and central Europe. Treating Norway spruce with jasmonate has long-lasting beneficial effects on tree resistance to damaging pests, such as the European spruce bark beetle Ips typographus and its fungal associates. The (epi)genetic mechanisms involved in such long-lasting jasmonate induced resistance (IR) have gained much recent interest but remain largely unknown. In this study, we treated 2-year-old spruce seedlings with methyl jasmonate (MeJA) and challenged them with the I. typographus vectored necrotrophic fungus Grosmannia penicillata. MeJA treatment reduced the extent of necrotic lesions in the bark 8 weeks after infection and thus elicited long-term IR against the fungus. The transcriptional response of spruce bark to MeJA treatment was analysed over a 4-week time course using mRNA-seq. This analysis provided evidence that MeJA treatment induced a transient upregulation of jasmonic acid, salicylic acid and ethylene biosynthesis genes and downstream signalling genes. Our data also suggests that defence-related genes are induced while genes related to growth are repressed by methyl jasmonate treatment. These results provide new clues about the potential underpinning mechanisms and costs associated with long-term MeJA-IR in Norway spruce.
Authors
Lars Sandved DalenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Lars Sandved DalenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Ceratocystis polonica and Heterobasidion parviporum are important fungal pathogens in Norway spruce (Picea abies). Tree susceptibility to these pathogens with respect to phenology was studied using artificial fungal inoculations at six stages of bud development, and assessed by measuring phloem necroses in the stems of 2- and 8-year-old trees. Tree capacity for resistance was assessed by measuring phloem nonstructural carbohydrates at each stage. Phloem necroses were significantly larger in trees with fungal versus control inoculations and increased significantly over time. Changes in nonstructural carbohydrates occurred in the trees; a significant decline in starch and a slight but significant increase in total sugars occurred over time. These results suggest that susceptibility to fungal pathogens and carbohydrate levels in the stems of the trees were related to fine-scale changes in bud development. A trade-off may occur between allocation of starch (the major fraction of the stem carbohydrate pool) to bud development/shoot growth versus defence of the stem. Previous tests of plant defence hypotheses have focused on herbivory on plants growing under different environmental conditions, but the role of phenology and the effect of pathogens are also important to consider in understanding plant resource allocation patterns.
Abstract
No abstract has been registered
Authors
Lars Sandved Dalen Heather Danforth John Einset Carl Gunnar Fossdal Aksel Granhus Harald Kvaalen Nina Elisabeth Nagy Paivi Liisa Rinne Linda Ripel Sissel Torre Gunnhild Søgaard Christiaan van der SchootAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Nina Elisabeth Nagy Lars Sandved Dalen D. L. Jones B. Swensen Carl Gunnar Fossdal Toril EldhusetAbstract
No abstract has been registered
Authors
Nina Elisabeth Nagy Carl Gunnar Fossdal Lars Sandved Dalen Anders Lønneborg Inger Heldal Øystein JohnsenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
O. Janne Kjønaas Harald Aalde Lars Sandved Dalen Helen Agnes de Wit Toril Drabløs Eldhuset Bernt-Håvard ØyenAbstract
No abstract has been registered
Abstract
No abstract has been registered