Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2006
Forfattere
Magnus Karlsson Ari M. Hietala Harald Kvaalen Halvor Solheim Åke Olson Jan Stenlid Carl Gunnar FossdalSammendrag
Norway spruce (Picea abies (L.) Karst.) has a natural distribution in the northern parts of Europe and Asia and is economically the most important tree species grown in the Nordic countries. A common threat to Norway spruce is the basidiomyceteous fungus Heterobasidion parviporum Niemelä and Korhonen. H. parviporum mainly attacks Norway spruce, although Siberian fir (Abies sibirica Ledeb.) and Scots pine (Pinus sylvestris L.) occasionally get infected. One obstacle to studying host/pathogen interaction in conifers has been the limited availability of mature clones for controlled inoculations, as genetic variation within the host material and the lack of replicates complicate interpretation of the results. Somatic embryogenesis, rooted cuttings, and tissue cultures may provide solutions for this problem. Tissue cultures from mature Norway spruce trees have been proposed as a possible model system for assessing resistance toward fungal pathogens. Recent data on chitinase isoform activity in the Norway spruce/H. parviporum pathosystem are encouraging; clonal variation was observed in the isoforms affected by inoculation, and the isoforms showing increased band intensity following bark inoculation by H. parviporum were also induced in the inoculated tissue cultures of the corresponding clones. To investigate the biological relevance of tissue cultures in host-pathogen interaction studies, transcript levels of selected host and pathogen genes in tissue cultures of Norway spruce were compared to those in bark of 33-year-old ramets of the same clones upon challenge by the pathogenic fungus H. parviporum. Similar transcript profiles of the pathogen and host genes were observed in both tissues, this supporting the use of tissue cultures as experimental material for the pathosystem. Higher transcript levels of the host genes phenylalanine ammonia lyase, peroxidase, and glutathione-S-transferase were observed in the more resistant clone #589 than in the less resistant clone #409 during the early stages of colonization. The most striking difference between the spruce clones was related to gene transcript levels of a class IV chitinase, which showed a continuous increase in clone #409 over the experimental period, with a possible association of this gene product to programmed cell death. Several of the fungal genes assayed were differentially expressed during colonization, including putative glutathione-S-transferases, laccase, cellulase, cytochrome P450 and superoxide dismutase genes. The transcriptional responses suggest an important role for the antioxidant systems of both organisms.
Forfattere
Joha W. Grobbelaar Michael J. Wingfield P. Bloomer Halvor Solheim Brenda D. WingfieldSammendrag
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Forfattere
Torstein KvammeSammendrag
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Forfattere
Torstein KvammeSammendrag
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Sammendrag
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Sammendrag
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