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.
2005
Forfattere
Øystein Johnsen Carl Gunnar Fossdal Nina Elisabeth Nagy Jørgen A.B. Mølmann OG Dæhlen Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Sammendrag
In field experiments, clones of Norway spruce [Picea abies (L.) Karst.] showed different degrees of resistance against pathogenic fungi inoculated into the bark that correlate with differences in polyphenolic parenchyma (PP) cells of the bark. Cells of spruce callus cultures, particularly towards the callus surface, resemble PP cells and this study looks at changes in callus cells during infection and the relative resistance of cultures from clones of low (weak) or high (strong) resistance to fungal infection. Callus cultures, initiated from trees with different resistance, were co-inoculated with Ceratocystis polonica (Siem.) C. Moreau and Heterobasidion annosum (Fr.) Bref. Callus cells from strong clones resemble PP cells of bark tissue from strong clones, having more polyphenolic bodies, while callus cells from weak clones are more similar to PP cells from those clones, which have less extensive phenolic bodies. Callus cultures from trees with weak resistance were more quickly overgrown by both species of pathogenic fungi than cultures from trees with strong resistance. Callus cells of infected cultures showed changes similar to activated PP cells of bark, including enhanced accumulation of polyphenolics. Phenolic bodies were more numerous and more extensive (larger and denser) in callus cells of strong versus weak clones under all conditions. Thus, callus cells may perform similar functions in defense as PP cells in the bark. Callus from trees of varying resistance seem to reflect the relative resistance of the trees from which they are derived, and this study indicates that some mechanisms of resistance can be studied using callus from trees of different resistance.
Sammendrag
Rhizoctonia solani was frequently isolated in the Italian Alps from ursery-grown European beech (Fagus sylvatica) seedlings displaying symptoms of cotyledon rot. Koch?s postulates were verified and mode of infection of the associated isolates was investigated with light and scanning electron microscopy. Population structure of the pathogen was investigated by scoring the anastomosis reaction type in pairings between different isolates from the same seedbed. One pathogen genotype showed a large distribution area within the seedbed, this implying that the inoculum had been building up in the seedbed over a longer time period. Hyphal anastomosis tests and sequence analysis of the internal transcribed spacer (ITS) region of ribosomal DNA indicated that the pathogen belongs to AG 2-1 of R. solani. ITS sequence analysis indicates that the isolates from beech are closely related to R. solani isolates causing a disease on tulip. The striking similarities between the two diseases are discussed.
Sammendrag
*Strawberry Fragaria × ananassa (cv. Korona) was inoculated with Botrytis cinerea by dipping berries in a conidial suspension. *Colonization by the pathogen was monitored using real-time PCR, ELISA and ergosterol assays, the first showing the highest sensitivity. The expression of pathogen B-tubulin and six polygalacturonases (Bcpg1-6) and three host defence genes (polygalacturonase-inhibiting protein (FaPGIP) and two class II chitinases) were monitored using real-time RT-PCR. *The maximum transcript levels of the host defence genes occurred at 16 h postinoculation (hpi) at the presumed initial penetration stage. The unique transcript profile of Bcpg2 over the 96-h incubation time and its high transcript levels relative to those of the other Bcpgs at 8-24 hpi suggest that the gene has a specific role in the penetration stage. *Bcpg1 was expressed constitutively at a relatively high level in actively growing mycelia throughout the experimental period. Comparison of the transcript profiles indicated that Bcpg1 and Bcpg3-6 were coordinately regulated.
Forfattere
Axel Schmidt Zeneli Gazmend Ari Hietala Carl Gunnar Fossdal Paal Krokene Erik Christiansen Jonathan GershenzonSammendrag
Det er ikke registrert sammendrag
2004
Redaktører
Arne StensvandSammendrag
Livssyklus gjennom året ble undersøkt for potetsikade. Sprøyting med pyretroid ga 5-20% avlingsøkning. Det arbeides med å utvikle en bekjempingsterskel for potetsikade.
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Forfattere
Guro BrodalSammendrag
Det er ikke registrert sammendrag
Forfattere
Helge Sjursen Arne Hermansen Elisa Gauslaa Ragnhild Nærstad Berit Nordskog Christer Magnusson Bonsak HammeraasSammendrag
Det er ikke registrert sammendrag