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
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Sammendrag
The difficulty in sub-culturing biotrophic fungi complicates etiological studies related to the associated plant diseases. By employing species-specific ITS sequence stretches, we used real-time PCR to investigate the spatial colonization profiles of T. areolata and a co-existing Phomopsis species in seedlings and saplings of Norway spruce showing bark necrosis. There was a strong gradient in the colonization level of T. areolata DNA along the lesion length, with the highest DNA amount levels being recorded in the area with dark brown phloem. The separate analysis of bark and wood tissues indicated that the initial spread of the rust to healthy tissues neighbouring the infection site presumably takes place in the bark. A Phomopsis species co-existing together with T. areolata in several cases showed very high DNA levels in the upper part of the lesion outside the brown phloem area, and even in the visually healthy proximal tissues above the lesions. This indicates that this ascomycete has a latent stage during early colonization of Norway spruce shoots. This mode of infection most probably explains the successful co-existence of Phomopsis with a biotrophic rust, as their mutual interest would be to avoid triggering host cell death.
Sammendrag
The root-rot causing fungus Heterobasidion annosum can attack both spruce and pine trees and is the economically most damaging pathogen in northern European forestry. We have monitored the H. annosum S-type (fairly recently named H. parviporum) colonization rate and expression of host chitinases and other host transcripts in Norway spruce material with differing resistances using quatitative realtime PCR. Transcript levels of three chitinases, representing classes I, II and IV, were monitored. Ramets of two 33-year-old clones differing in resistance were employed as host material and inoculation and wounding was performed. 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 pathogen perception and host defense signal transduction. This an earlier experiments using mature spruce clones as substrate indicate that it is the speed of the host response and not maximum amplitude of the host response that is the most crucial component in an efficient defense in Norway spruce toward pathogenic fungi such as H. annosum.
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Fusarium-toksiner i korn utgjør en helserisiko for mennesker og dyr, og fra 2006 har Mattilsynet fastsatt grenseverdier for innhold av noen slike toksiner i korn. Denne utgivelsen av Bioforsk TEMA omtaler dyrkingsforhold som har betydning for angrep av Fusarium og utvikling av toksiner i korn. På side 3 er det vist en tabell for vurdering av risiko for utvikling av Fusarium-toksiner i vekstsesongen.
Forfattere
jihong liu clarke Sonja Klemsdal Erling Fløistad A.K. Hvoslef-Eide Sissel Haugslien Roe Moe Dag-Ragnar BlystadSammendrag
Poinsettia, Euphorbia pulcherrima Willd & Klotsch, is an ornamental flower which grows in many countries. Two viruses i.e. poinsettia mosaic virus (PnMV) and poinsettia cryptic virus (PnCV) can cause diseases on modern poinsettia cultivars. To produce virus-resistant poinsettia plants, genetic transformation has been considerated. Since there is no established method available for the transformation of poinsettia, we have chosen an electrophoresis-based transformation method to generate poinsettia transformants. The main advantage of this method is that we can avoid the time-consuming tissue culture and regeneration procedure. To develop a reliable transformation method, the green fluorescent protein (GFP) gene has been used as a reporter gene. Here, we report our preliminary results.
Forfattere
jihong liu clarke Sonja Klemsdal Erling Fløistad A.K. Hvoslef-Eide Sissel Haugslien R Moe Dag-Ragnar BlystadSammendrag
Poinsettia (Euphorbia pulcherrima) is a major ornamental pot plant in many countries. Two viruses, poinsettia mosaic virus (PnMV) and poinsettia cryptic virus, often infect modern poinsettia cultivars. To produce virus-resistant poinsettia plants, genetic engineering has been considered. Since there is no established method available for the transformation of poinsettia, we have chosen an electrophoresisbased transformation method to generate poinsettia transformants. The main advantage of this method is that we can avoid the time-consuming tissue culture and regeneration procedure. To develop a reliable transformation method, the green fluorescent protein (GFP) gene has been used as a reporter gene. Here we report our preliminary results.
Sammendrag
Artikkelen skildrar effekten av klimatiske tilhøve (nedbør og temperatur) før sporekastinga tar til om våren på sporemodninga/sporekastinga seinare i sesongen hos epleskurvsoppen. Di fuktigare klimaet er siste månaden før sporekastinga tar til (som regel rundt grøn spiss), di større mengde sporar vert kasta tidleg i sesongen. Data er basert på innsamla bladverk med soppsmitte frå 11 ulike land.
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