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.
2012
Authors
Carl Gunnar Fossdal Nina Elisabeth Nagy Ari Hietala Harald Kvaalen Rune Slimestad Steve Woodward Halvor SolheimAbstract
No abstract has been registered
Authors
Flavio Paoletti Antonio Raffo Kristian Thorup-Kristensen Randi Seljåsen Torfinn Torp Nicolaas Busscher Angelica Ploeger Johannes KahlAbstract
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A survey of the prevalence of skin blemish diseases in potatoes after the growing seasons of 2008 and 2009 was carried out on 247 potato lots representing different cultivars and production regions in Norway. The results showed the presence of silver scurf (Helminthosporium solani) in all lots. Skin spot (Polyscytalum pustulans) and black scurf (Rhizoctonia solani) were found in 80% of the lots, and black dot (Colletotrichum coccodes) and common scab caused by Streptomyces spp. were present in 50–70%. Also, powdery scab (Spongospora subterranea) occurred in 65–80% of the lots, and root-lesion nematodes (Pratylenchus spp.) were detected in 60% of the sub-samples that exhibited symptoms of common scab.
Authors
Patrick Conaghan Pádraig O'Kiely Magnus Halling Frank O'Mara Lars NesheimAbstract
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Authors
Nina Elisabeth Nagy Simon Ballance Harald Kvaalen Carl Gunnar Fossdal Halvor Solheim Ari HietalaAbstract
Heterobasidion parviporum, a common pathogenic white-rot fungus in managed Norway spruce forests in northern and central Europe, causes extensive decay columns within stem heartwood of the host tree. Infected trees combat the lateral spread of decay by bordering the heartwood with a fungistatic reaction zone characterized by elevated pH and phenol content. To examine the mode of fungal feeding in the reaction zone of mature Norway spruce trees naturally infected by H. parviporum, we conducted spatial proWling of pectin and hemicellulose composition, and established transcript levels of candidate fungal genes encoding enzymes involved in degradation of the diVerent cell wall components of wood. Colonized inner heartwood showed pectin and hemicellulose concentrations similar to those of healthy heartwood, whereas the carbohydrate proWles of compromised reaction zone, irrespective of the age of fungal activity in the tissue, indicated selective fungal utilization of galacturonic acid, arabinose, xylose and mannose. These data show that the rate of wood decay in the reaction zone is slow. While the up-regulation of genes encoding pectinases and hemicellulases preceded that of the endoglucanase gene during an early phase of fungal interaction with xylem defense, the manganese peroxidase gene showed similar transcript levels during diVerent phases of wood colonization. It seems plausible that the reaction zone components of Norway spruce interfere with both lignin degradation and the associated co-hydrolysis of hemicelluloses and pectin, resulting in a prolonged phase of selective decay.
Abstract
The development of new tools able to select specific plant tissue is crucial for gene expression studies. During the last years, the use of laser microdissection, mainly tested on herbaceous plant tissue, has been found to be a useful technique for these purposes. This method is poorly tested on woody species, and so far no studies of gene expression have been applied on forest trees. For this reason the present work proposes the optimization of a functional protocol using laser microdissection pressure catapulting (LMPC) and real-time reverse transcription–polymerase chain reaction (RT-PCR) in bark stem tissue of Norway spruce (Picea abies). Bark tissue fragments were collected from Norway spruce trees and sliced with a cryostat. RNA was extracted from both whole cross-sections and microdissected bark cells. The feasibility of the method was confirmed by the amplification of the α-tubulin, an endogenous gene of P. abies, with efficiency comparable to that obtained from non-microdissected tissue. The proposed protocol, here adapted for bark tissue of woody species, represents a useful tool in a wide range of hosts that, unlike herbaceous plants, have scarcely been considered up to now.