Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2004
Authors
Christer Magnusson Hans Overgaard Hans Nyeggen Karl Thunes Solveig Haukeland Bonsak HammeraasAbstract
In this survey of 2002, 600 samples were collected from 83 forest blocks in the counties Akershus, Buskerud, Oppland and Østfold. The sampling activity involved 16 municipallities situated mainly within the three zone sites A, B, and C. Samples from Scots pine (Pinus sylvestris) formed 89%, while samples of Norway spruce (Picea abies) made up 10% of the total sample volume. Timber and forest debris were the most common objects sampled. Sixty-five percent of the pine samples and 81% of the spruce samples showed signs of Monochamus activity. Nematodes were common and occurred in 94% of the samples analysed. Thirteen samples of pinewood were positive for the genus Bursaphelenchus. Bursaphelenchus mucronatus was recorded for the third time in Norway, and was detected in forest debris attacked by Monochamus at Bjørdalen in the municipality of Eidsberg in the county of Østfold. The pine wood nematode Bursaphelenchus xylophilus was not detected in this survey.
Abstract
In this survey of 2003, 600 samples were collected from 96 forest blocks in the counties of Aust-Agder and Vest-Agder in southern Norway. The sampling activity involved 19 municipalities situated mainly within the two zone sites D and E close to Kristiansand and Arendal. Samples from Scots pine (Pinus sylvestris) formed 92%, while samples of Norway spruce (Picea abies) made up 8% of the total sample volume. Timber and forest debris was the most common objects sampled. Ninety-eight percent of the samples, regardless of tree species, showed signs of Monochamus activity. Nematodes were common and occurred in 90% of the samples analysed. Eight samples of pinewood were positive for the genus Bursaphelenchus. This genus did not occur in spruce. Bursaphelenchus mucronatus was detected in 6 samples of forest debris of pine attacked by Monochamus and collected in the county of Aust-Agder. In the municipality of Evje and Hornes B. mucronatus was detected at Skjerkelia and Sutestad. In the municipality of Froland the nematode was found in two samples from Budalsfjellet, and in one sample from Mjålandsvatn. In the municipality of Birkenes one sample from Vågsdalen contained B. mucronatus. This is the fourth report on the occurrence of B. mucronatus in Norway. The pine wood nematode Bursaphelenchus xylophilus was not detected.
Abstract
Introduction: The objectives of the present study were to monitor H. annosum colonization rate (Hietala et al., 2003) and expression of host chitinases in clonal Norway spruce material with differing resistances. Transcript levels of three chitinases, representing classes I, II and IV, were monitored with real-time PCR.Material and MethodsInoculation experiment: Ramets of two 32 -year-old clones differing in resistance were employed as host material. Inoculation and wounding was performed. A rectangular strip containing phloem and cambium, with the inoculation site in the middle, was removed 3, 7 and 14 days after inoculation.Quantification of fungal colonizationMultiplex real-time PCR detection of host and pathogen DNA was performed (Hietala et al., 2003). Quantification of gene expression: Chitinase levels were monitored with Singleplex real-time PCR.Results and ConclusionsThe colonization profiles provided by the quantitative multiplex real-time PCR procedure (Hietala et al., 2003), when combined with spatial and temporal transcript profiling of 3 chitinases, provide a useful basis for identifying defense related genes, and for assessing their impact on pathogen colonization rates.Three days after inoculation, comparable colonization levels were observed in both clones in the area immediately adjacent to inoculation. Fourteen days after infection, pathogen colonization was restricted to the area immediately adjacent to the site of inoculation for the strong clone (589), but had progressed further into the host tissue in the weak (409) clone.Transcript levels of the class II and IV chitinases increased following wounding or inoculation, while the transcript level of the class I chitinase declined following these treatments. Transcript levels of the class II and class IV chitinases were higher in areas immediately adjacent to the inoculation site in 589 than in similar sites in 409 three days after inoculation, suggesting that the clones differ in the rate of chitinase-related signalperception.
Abstract
We have monitored the H. annosum colonization rate and expression of host chitinases in Norway spruce material with differing resistances. Transcript levels of three chitinases, representing classes I, II and IV, were monitored with real-time PCR. Ramets of two 32 -year-old clones differing in resistance were employed as host material and inoculation and wounding was performed. Quantification of fungal colonization: Multiplex real-time PCR detection of host and pathogen DNA was performed. Chitinase transcript levels were also monitored with real-time PCR. Three days after inoculation, comparable colonization levels were observed in both clones in the area immediately adjacent to inoculation. Fourteen days after infection, pathogen colonization was restricted to the area immediately adjacent to the site of inoculation for the strong clone (589), but had progressed further into the host tissue in the weak clone (409). Transcript levels of the class II and IV chitinases increased following wounding or inoculation, while the transcript level of the class I chitinase declined following these treatments. Transcript levels of the class II and class IV chitinases were higher in areas immediately adjacent to the inoculation site in 589 than in similar sites in 409 three days after inoculation, suggesting that the clones differ in the rate of chitinase-related signal perception. The spatiotemporal accumulation patterns obtained for the two clones used are consistent with their resistance classifications, these warranting further and more detailed studies on these chitinases.
Abstract
Pathogen colonization and transcript levels of three host chitinases,putatively representing classes I, II, and IV, were monitored with real-time PCR after wounding and bark infection by Heterobasidion annosum in 32-year-old trees of Norway spruce (Picea abies) with low (clone 409) or high (clone 589) resistance to this pathogen. Three days after inoculation, comparable colonization levels were observed in both clones in the area immediately adjacent to inoculation. At 14 days after infection, pathogen colonization was restricted to the area immediately adjacent to the site of inoculation for clone 589 but had progressed further into the host tissue in clone 409. Transcript levels of the class II and IV chitinases increased after wounding or inoculation, but the transcript level of the class I chitinase declined after these treatments. Transcript levels of the class II and class IV chitinases were higher in areas immediately adjacent to the inoculation site in clone 589 than in similar sites in clone 409 3 days after inoculation. This difference was even more pronounced 2 to 6 mm away from the inoculation point, where no infection was yet established, and suggests that the clones differ in the rate of chitinase-related signal perception or transduction. At 14 days after inoculation, these transcript levels were higher in clone 409 than in clone 589, suggesting that the massive upregulation of class II and IV chitinases after the establishment of infection comes too late to reduce or prevent pathogen colonization.
Authors
Karl Thunes John Skartveit Ivar Gjerde Josef Stary Torstein Solhøy Arne Fjellberg Sverre Kobro Sueo Nakahara R. Zur Strassen Gijsbertus Vierbergen Ryszard Szadziewski Daniel V. Hagan William. L. Grogan Jr Terje Jonassen Kjetil Aakra Johannes Anonby Lita Greve Berend Aukema Kai Heller Verner Michelsen Jean-Paul Haenni Alexandr F. Emeljanov Per Douwes Kai Berggren Jutta Franzen R. Henry L. Disney Sabine Prescher Kjell Arne Johanson Boris Mamaev Sigitas Podenas Stig Andersen Stephen D. Gaimari Emilia Narchuk Geir Einar Ellefsen Søli Laszlo Papp Fred Midtgaard Arild Andersen Michael von Tschirnhaus Gerhard Bächli Kjell Magne Olsen Hans A. Olsvik Mihaly Földvari Jan Emil Raastad Lars Ove Hansen Per DjursvollAbstract
No abstract has been registered
Authors
Fadi Suliman Helen French Lars Egil Haugen Petter D. Jenssen Bjørn KløveAbstract
No abstract has been registered
Abstract
Using information from a regional survey of vascular plants of 130 sites in western Norway, a selection of sites based on a heuristic iterative complementarity-based nature reserve selection procedure was performed. The results indicate that conservation of traditionally managed hay meadows is of major importance as they contributed 60.1% of all native species recorded; afforested grasslands (deciduous woodlands < 70 years old) contributed 26.8%, whereas artificially fertilized hay meadows and intensively cultivated grasslands taken together contributed 13.1% of the species. The species composition of the meadows was significantly nested. Thus, if you conserve the most species-rich meadows, you also conserve most of the species in the less species-rich meadows. Nestedness in meadows was significantly correlated with within-meadow habitat diversity and soil pH. The most species-rich meadows were traditional meadows, characterized by high habitat diversity and high soil pH. These meadows will support nearly all species including habitat specialists and regionally rare species, whilst artificially fertilized hay meadows only support the generalist subset, i.e. common species. Area was not significantly correlated with nestedness suggesting that it is more important to cover many habitats than to preserve large traditional meadows just because they are large.
Authors
Carl Gunnar Fossdal Øystein Johnsen Nina Elisabeth Nagy R Baumann Jørgen A.B. Mølmann Tore SkrøppaAbstract
Introduction: Survival and competitive successes of boreal forest trees depend on a balance between exploiting the full growing season and minimising frost injury through proper timing of hardening in autumn and dehardening in spring. Our research indicates that the female parents of Norway spruce adjust these timing events in their progeny according to the prevailing temperature conditions during sexual reproduction. Reproduction in a cold environment advances bud-set and cold acclimation in the autumn and dehardening and flushing in spring, whereas a warm reproductive environment delays these progeny traits by an unknown non-Mendelian mechanism. We are now looking for molecular mechanisms that can explain this “epigenetic” phenomenon. Material and methods: We have performed identical crosses with the same Norway spruce (Picea abies) parent, as discussed by Skrøppa & Johnsen (1994) and Johnsen et al. (1995), in combination with timed temperature treatments during shorter and longer periods from female meiosis, pollen tube growth, syngamy and embryogenesis and tested the progenies for bud-set and frost hardiness. We have followed the transcription of the spruce phytochromes PHYO, PHYP and PHYN and the class IV chitinase PaChi4 using Quantitative Multiplex Real-Time PCR. Results and conclusions: The effect of temperature on Adaptive properties is most likely a response to accumulated heat during embryogenesis and seed maturation. Our first attempt to look for a molecular mechanism has revealed that transcription of PHYO, PHYP and PHYN and the class IV chitinase PaChi4 (relative to alphaTubulin) all show higher transcription levels in progenies born under cold conditions than their full-sibs born under warmer conditions. This result is consistent with preliminary findings that methylation of cytosine in total DNA is higher in progenies reproduce under warm conditions than their colder full-sib counterparts. If these observations are related to methylation or other epigenetic effects, we may explain why progenies with a memory of a past time cold embryogenesis are more sensitive to short days than their full-sibs with a warmer embryonic history.
Authors
Carl Gunnar Fossdal Øystein Johnsen Rüdiger Baumann Jørgen A. Mølmann Ola Gram Dæhlen Nina Elisabeth Nagy Tore SkrøppaAbstract
Research indicate that the female parents of Norway spruce adjust these timing events in their progeny according to the prevailing temperature conditions during seed development. Reproduction in a cold environment advances bud-set and cold acclimation in the autumn and dehardening and flushing in spring, whereas a warm reproductive environment delays these progeny traits by an unknown non-Mendelian mechanism. We have performed identical crosses in combination with timed temperature treatments during shorter and longer periods from female meiosis, pollen tube growth, syngamy and embryogenesis, tested the progenies for bud-set and frost hardiness, and concluded that the effect of temperature most likely is a response to accumulated heat during embryogenesis and seed maturation. Our first attempt to look for a molecular mechanism has revealed that transcription of PHYO, PHYP and PHYN and the class IV chitinase PaChi4 (using RealTime PCR) all show higher transcription levels in progenies born under cold conditions than their full-sibs born under warmer conditions. This result is consistent with preliminary findings that methylation of cytosine in total DNA is higher in progenies reproduce under warm conditions than their colder full-sib counterparts. If these observations are related to methylation, we may explain why progenies with a memory of a past time cold embryogenesis are more sensitive to short days than their full-sibs with a warmer embryonic history.