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.
2008
Forfattere
Nina TrandemSammendrag
Det er ikke registrert sammendrag
Forfattere
Nina TrandemSammendrag
Det er ikke registrert sammendrag
Forfattere
Nina TrandemSammendrag
Det er ikke registrert sammendrag
Forfattere
jihong liu clarke Carl Jonas Jorge Spetz Sissel Haugslien Dag-Ragnar Blystad Merete Wiken Dees Shaochen Xing Roar MoeSammendrag
Abstract Poinsettia (Euphorbia pulcherrima Willd. Ex Klotzsch), is a contemporary symbol of Christmas in most parts of the world. Today, Europe and North America represent the largest volume of production and sales, but demand is growing quickly in the other regions as poinsettia becomes more popular each year. In Norway, poinsettia is one of the most important pot plants, with a yearly production close to 6 million plants. Its ornamental value and innovation potential have laid the foundation for extensive research in Norway and elsewhere. Poinsettia mosaic virus (PnMV) can cause diseases in modern poinsettia cultivars. PnMV is a single-stranded, positive-sense RNA virus that belongs to the family Tymoviridae. Infection of poinsettia plants with PnMV results in mosaic symptoms during parts of the growing season, which in turn decreases the commercial value of this ornamental plant. Thus, growers are interested in the potential benefits of growing PnMV-free poinsettias. PnMV-free poinsettia plants can be obtained by heat treatment or in vitro culture of apical meristems, which are time-consuming and cost-ineffective methods. There is a need for a new and effective alternative approach, like Agrobacterium-mediated transformation, which can overcome these difficulties. Therefore, we have developed an Agrobacterium-mediated transformation approach for poinsettia for the first time. Internode stem explants of poinsettia cv. Millenium were transformed by Agrobacterium tumefaciens, strain LBA 4404, harbouring three hairpin (hp) RNA gene constructs to induce RNA silencing-mediated resistance to Poinsettia mosaic virus (PnMV). Prior to transformation, an efficient somatic embryogenesis system was developed for poinsettia cv. Millenium in which about 75 % of the explants produced somatic embryos. In five experiments utilizing 868 explants, 18 independent transgenic lines were generated. Stable integration of transgenes into the poinsettia nuclear genome was confirmed by PCR and Southern blot analysis. Both single- and multiple-copy transgene integration into the poinsettia genome were detected among transformants. Northern blot analysis confirmed the production of transgene-derived small interfering RNAs (siRNAs). Transgenic lines showing resistance to mechanical inoculation of PnMV were detected by double antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISA). The Agrobacterium-mediated transformation methodology developed in the current study should facilitate improvement of this ornamental plant with enhanced disease resistance, quality improvement and desirable colour alteration. Because poinsettia is a non-food, non-feed plant and is not propagated through sexual reproduction, this is likely to be more acceptable even in areas where genetically modified crops are currently not cultivated.
Sammendrag
Poinsettia (Euphorbia pulcherrima Willd. Ex Klotzsch), is a contemporary symbol of Christmas in most parts of the world. Today, Europe and North America represent the largest volume of production and sales, but demand is growing quickly in the other regions as poinsettia becomes more popular each year. In Norway, poinsettia is one of the most important pot plants, with a yearly production close to 6 million plants. Its ornamental value and innovation potential have laid the foundation for extensive research in Norway and elsewhere. Poinsettia mosaic virus (PnMV) is a RNA virus that belongs to the family Tymoviridae. Infection of poinsettia plants with PnMV results in mosaic symptoms during parts of the growing season and decrease the commercial value of this ornamental plant. Thus, growers are interested in the potential benefits of growing PnMV-free poinsettias. PnMV-free poinsettia plants can be obtained by heat treatment or in vitro culture of apical meristems, which are time-consuming and cost-ineffective methods. There is thus an urgent need for a new approach, like Agrobacterium-mediated transformation, which can overcome these difficulties. We have therefore developed an Agrobacterium-mediated transformation approach for poinsettia. Transgenic poinsettia plants with improved resistance against PnMV by expressing hairpin RNA constructs which targeted various regions of the virus genome were produced. Mechanical inoculation of PnMV and subsequent enzyme-linked immunosorbent assay (ELISA) confirmed the PnMV resistance. The siRNA analysis has demonstrated gene silencing mediated resistance. The PnMV resistant transgenic poinsettia lines produced are in the process of being commercialized. Because poinsettia is a non-food, non-feed plant and is not propagated through sexual reproduction, this is likely to be more acceptable even in areas where genetically modified crops are currently not cultivated.
Forfattere
Trond HofsvangSammendrag
Det er ikke registrert sammendrag
Forfattere
Claire E. Sansford Richard H. A. Baker John P. Brennan Frank Ewert Beniamino Gioli Alan Inman Anne Kinsella Håkon A. Magnus Franco Miglietta Gordon M. Murray Angelo Porta-Puglia John Roy Porter Trond Rafoss Luca Riccioni Fionnula ThorneSammendrag
Tilletia indica, soppen som forårsaker sjukdommen Karnal bunt i hvete, er listet som en I/AI karanteneskadegjører i EU (Anon., 2000a). Dette betyr at den anses som fraværende fra EU området, er potensielt skadende og dermed ikke ønsket innført til EU. Oppføringen som en karanteneskadegjører for EU er resultatet av en pest risiko analyse (PRA) (Sansford, 1996, 1998), som vurderte potensialet for innførsel, etablering og uønskede virkninger for Storbritannia og EU etter de første rapportene om utbrudd av denne sjukdommen i USA i 1996 (Ykema et al., 1996). Denne PRA"en ble oppdatert i 2004 (Sansford, 2004) og nylig grundig revidert (Sansford et al., 2006) for EU området. Denne nye EU-PRA"en fortsetter å støtte oppfatningen om at T. indica har potensial til å ankomme, etablere seg og forårsake uønskede økonomiske virkninger ute i store deler av hvete dyrkings områdene i EU. To nylig publiserte artikler (Jones, 2007a,b) har utfordret denne oppfatningen og EU-PRA"en for T. indica (Sansford et al., 2006). I dette brevet oppsummerer vi arbeidet av et fireårig samarbeidsstudie og går igjennom hovedpunktene som Jones (2007a,b) tar opp og tilbakeviser hans konklusjoner, spesielt angående (i) tidligere muligheter for innførsel av patogene til Europa; (ii) de klimatiske kravene for gjennommføring av livssyklus for T. indica, som leder til sjukdommen Karnal bunt; (iii) inokulum terskler; (iv) potentsiell økonomisk skade forårsaket av sjukdommen i Europa; og (v) kostnader ved kontroll og bekjemping. De fulle resultatene fra studiet er tilgjengelige on line (http://karnalpublic.pestrisk.net/) sammen med publiserte resultater for teliospore overlevelse og spiring i Europa (Inman et al., 2008) og mottakelighet i europeiske hvetesorter for T. indica (Riccioni et al., 2008).
Sammendrag
Foredrag om nyere prosjekter på flerårig vandrende ugras, hovedsakelig kveke, åkertistel og åkerdylle.
Forfattere
Ari Lehtinen Asko Hannukkala Björn Andersson Arne Hermansen Vinh Hong Le Ragnhild Nærstad May Bente Brurberg Bent J Nielsen Jens G Hansen Jonathan YuenSammendrag
A total of 743 single-lesion isolates of Phytophthora infestans were collected in summer 2003 from Denmark, Finland, Norway and Sweden. Most of the isolates were tested for mating type, snd subsets for sensitivity to fungicides and virulence (host specific pathogenicity). Approximately 60 % of the isolates were A1 mating type in each country. Both mating types were present in 40 % of the fields where more than one isolate was tested,indicating strong potential for sexual reproduction. The proportion of metalaxyl-resistant isolates dropped under 15 % from the 60% observed in the early 1990s in Norway and Finland, possibly due to lower selection pressure because of decreased use of metalaxyl. PropamocarbHCl sensitivity remained unchanged in the Nordic countries compared to the situation in 1997-2000 in Finland. Four isolates collected from Finland and Sweden were able to sporulate in the presence of this fungicide at a concentration of 1000 mg L-1. In Norway and Finland the frequencies of virulence factors and pathotypes remained nearly unchanged since 1990s, but the mean number of virulence factors per isolate increased from 5.6 to 6.3. In Denmark and Sweden virulence factors 2 and especially 6 were more common than in Norway and Finland. In addition, in the Swedish population the frequencies of pathotypes were quite even while in other countries pathotype 1.3.4.7.10.11 was most prevalent.
Sammendrag
Svartskurv kan gi mange ulike symptomer i potet. Et av disse er vekstsprekk i knoller.