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
Guro Brodal Oleif Nilsen Elen Ingerd Skow Hofgaard Heidi Udnes Aamot Erik Lysøe Sonja KlemsdalSammendrag
Det er ikke registrert sammendrag
Forfattere
Guro Brodal Oleif Nilsen Elen Ingerd Skow Hofgaard Heidi Udnes Aamot Erik Lysøe Sonja KlemsdalSammendrag
Det er ikke registrert sammendrag
Forfattere
Mathias Pasquali Erik Lysøe Publikasjonsforfatter Keong Seong Jon Menke J. Xu H. Corby KistlerSammendrag
To understand mycotoxin accumulation and the infection cycle of the wheat head blight pathogen Fusarium graminearum sensu stricto,fungal gene expression profiles were monitored during plant infection. Strains containing mutations in genes for three transcription factors were found to control deoxynivalenol (DON) accumulation in planta and pathogenicity. Expression profiles were compared between wildtype and these mutants during infection of wheat. Mutants deleted for the StuA gene were greatly decreased in sporulation and produced no perithecia in culture. Unlike "stuA mutants in F. oxysporum, F. graminearum "stuA mutants were greatly reduced in pathogenicity. Reduced pathogenicity may be due to decreased DON levels in planta, which in the mutant were
Sammendrag
The filamentous fungus Fusarium graminearum causes extensive losses on cereals world-wide and contaminates harvested grain with mycotoxins, whose levels in the food supply are strictly regulated. We deleted the FgStuA gene in Fusarium graminearum and demonstrate its involvement in several different processes, such as spore development, pathogenicity and secondary metabolism. The FgStuA protein is a members of the APSES family which regulate morphogenesis and virulence in ascomycetes. FgStuA is closely related to FoStuA in F. oxysporum and StuA in Aspergillus, but unlike FoStuA mutants, the FgStuA mutants were greatly reduced in pathogenicity both on wheat and apple slices. Reduced pathogenicity may be due to decreased levels of trichothecene mycotoxins (
Sammendrag
På seinsommaren 2008 vart bladskimmel for første gong påvist i lisespringfrø (Impatiens walleriana) i Noreg. Sjukdomen fører til misvekst, bladgulning, knopp og bladfall. Store angrep er registrert i Oslo og Bergen. Mikroskop-studium og molekylære analysar tilseier at det er arten Plasmopara obducens som har gitt skaden
Forfattere
Brita Toppe Maria Herrero May Bente BrurbergSammendrag
Fusarium foetens ble for første gang påvist i Norge i 2002 i Begonia x hiemalis. Deretter er betydlige angrep registrert i hiemalisbegonia, i den nye vertsplanten Begonia cheimanta (juleglede) og i den nye kultivaren Betulia. Utgang på mer enn 50% er observert i alle de tre vertsplantene i ulike gartneri. For identifikasjon av F. foetens ble det brukt real-time PCR basert på (mtSSU)rDNA.
Forfattere
Arne Hermansen May Bente Brurberg Vinh Hong Le Abdelhameed Elameen Ragnhild Nærstad Björn Andersson Asko Hannukkala Ari Lehtinen Bent Nielsen Jens G. Hansen Jonathan YuenSammendrag
Variability of the Nordic Phytophthora infestans population
Forfattere
Maria Herrero Brita Toppe Trond RafossSammendrag
In November 2002, P.ramorum was detected for the first time in Norway (1). It was isolated from Rhododendron catawbiense imported earlier the same year. After the first detection the Norwegian Food Safety Authority has carried out surveys from 2003 to 2006. The surveys were first directed to nurseries and garden centres. Most of the positive findings were on Rhododendron spp., but one sample of Pieris japonica, one of Kalmia sp., one of Syringa sp. and one of Viburnum sp. were also positive. In 2005 and 2006, P. ramorum was isolated from well-established viburnum and rhododendron plants in private gardens, parks and public greens. Infections were detected on well-established plants from 9 different outdoor sites. While the positive samples from nurseries were spread over the country, the positives found on well-established plants were concentrated in and around the cities of Bergen and Stavanger on the southwestern coast of Norway. This part of the country has cool summers, mild winters and more than 2000 mm of annual precipitation. In 2006, P. ramorum was found in private gardens in the eastern part of the country on young recently introduced plants. P. ramorum was found in 12 import shipments, mainly on rhododendron, but also on a viburnum sample.
Forfattere
Maria Herrero Arthur de Cock Sonja Klemsdal Brita ToppeSammendrag
In 2006, a survey of root diseases in greenhouse pot plants started in Norway. During this survey an unknown Phytophthora sp. was isolated several times. The ITSrDNA region of these isolates were sequenced and compared to the GenBank database. The determined ITS sequences of the isolates matched the sequence of Phythophthora taxon niederhauserii.The diseased plants originated from 5 different greenhouse sites. Isolates were obtained from ivy (Hedera helix), begonia-hybrids (Begonia × hiemalis and Begonais × cheimantha), gloxinia (Sinninga speciosa) and kalanchoë (Kalanchoë blossfeldiana). Symptoms on begonia, gloxinia and ivy included necrotic roots and stems with the necrosis advancing to the leaves via the petioles. In the case of ivy and gloxinia, wilting of the whole plant was observed. In kalanchoë only discoloration of roots and reduced plant growth was seen. Koch postulates have been completed for ivy and gloxinia. The pathogen caused aggressive root-rot in 22 different ivy-cultivars.
Sammendrag
In 1996, a survey on cavity spot started in Norway. Among the Pythium species isolated from the lesions a pathogenic Pythium was found that could not be identified neither by morphological nor by molecular methods (ITS sequencing). This Pythium sp. was repeatedly detected using specific primers developed for this propose and in many cases isolated from cavity spots lesions. The isolates from the new species do not produce zoospores. Oogonia are smooth walled and mostly intercalary with an average size about 20µm. Oospores are aplerotic with an average diameter approximately 17 µm and wall less then 2 µm thick. Antheridia are mostly monoclinous with a sort stalk or sessil, but diclinous antheridia are also common. The modal number of antheridia per oogonium is one or two. Some differences are observed between the isolates studied. Some isolates have a daily growth rate of ca 23 mm on PCA at 25 °C while others have a growth rate around 28 mm. The isolates that grow slower have a tendency to produce one antheridium per oogonium while the isolates with higher growth rates normally produce two. These two groups could also be differentiated based on their ITS sequences which showed 97.8% identity in the 955 base pair rDNA fragment. By using the developed PCR primers it is possible to detect isolates that do not produce the sexual stage in single cultures. These isolates have the same ITS sequence and a similar growth rate and pattern than the fast growing fertile ones.