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.
2017
Forfattere
John P. Clarkson Rachel J. Warmington Peter G. Walley Matthew Denton-Giles Martin J. Barbetti Guro Brodal Berit NordskogSammendrag
Sclerotinia species are important fungal pathogens of a wide range of crops and wild host plants. While the biology and population structure of Sclerotinia sclerotiorum has been well-studied, little information is available for the related species S. subarctica. In this study, Sclerotinia isolates were collected from different crop plants and the wild host Ranuculus ficaria (meadow buttercup) in England, Scotland, and Norway to determine the incidence of Sclerotinia subarctica and examine the population structure of this pathogen for the first time. Incidence was very low in England, comprising only 4.3% of isolates while moderate and high incidence of S. subarctica was identified in Scotland and Norway, comprising 18.3 and 48.0% of isolates respectively. Characterization with eight microsatellite markers identified 75 haplotypes within a total of 157 isolates over the three countries with a few haplotypes in Scotland and Norway sampled at a higher frequency than the rest across multiple locations and host plants. In total, eight microsatellite haplotypes were shared between Scotland and Norway while none were shared with England. Bayesian and principal component analyses revealed common ancestry and clustering of Scottish and Norwegian S. subarctica isolates while English isolates were assigned to a separate population cluster and exhibited low diversity indicative of isolation. Population structure was also examined for S. sclerotiorum isolates from England, Scotland, Norway, and Australia using microsatellite data, including some from a previous study in England. In total, 484 haplotypes were identified within 800 S. sclerotiorum isolates with just 15 shared between England and Scotland and none shared between any other countries. Bayesian and principal component analyses revealed a common ancestry and clustering of the English and Scottish isolates while Norwegian and Australian isolates were assigned to separate clusters. Furthermore, sequencing part of the intergenic spacer (IGS) region of the rRNA gene resulted in 26 IGS haplotypes within 870 S. sclerotiorum isolates, nine of which had not been previously identified and two of which were also widely distributed across different countries. S. subarctica therefore has a multiclonal population structure similar to S. sclerotiorum, but has a different ancestry and distribution across England, Scotland, and Norway.
Sammendrag
Helminthosporium solani causes silver scurf, which affects the quality of potato. The biocontrol agent Clonostachys rosea greatly limited the severity of silver scurf symptoms and amount of H. solani genomic DNA in laboratory experiments. Transcriptomic analysis during interaction showed that H. solani gene expression was highly reduced when coinoculated with the biocontrol agent C. rosea, whereas gene expression of C. rosea was clearly boosted as a response to the pathogen. The most notable upregulated C. rosea genes were those encoding proteins involved in cellular response to oxidative stress, proteases, G-protein signaling, and the methyltransferase LaeA. The most notable potato response to both fungi was downregulation of defense-related genes and mitogen-activated protein kinase kinase kinases. At a later stage, this shifted, and most potato defense genes were turned on, especially those involved in terpenoid biosynthesis when H. solani was present. Some biocontrol-activated defense-related genes in potato were upregulated during early interaction with C. rosea alone that were not triggered by H. solani alone. Our results indicate that the reductions of silver scurf using C. rosea are probably due to a combination of mechanisms, including mycoparasitism, biocontrol-activated stimulation of plant defense mechanisms, microbial competition for nutrients, space, and antibiosis.
Sammendrag
The genus Microbacterium contains bacteria that are ubiquitously distributed in various environments and includes plant-associated bacteria that are able to colonize tissue of agricultural crop plants. Here, we report the 3,508,491 bp complete genome sequence of Microbacterium sp. strain BH-3-3-3, isolated from conventionally grown lettuce (Lactuca sativa) from a field in Vestfold, Norway. The nucleotide sequence of this genome was deposited into NCBI GenBank under the accession CP017674.
Forfattere
Merete Wiken Dees Renata Lebecka Juliana Perminow Robert Czajkowski Anna Grupa Agata Motyka Sabina Zoledowska Jadwiga Śliwka Ewa Lojkowska May Bente BrurbergSammendrag
Soft rot and blackleg of potato caused by pectinolytic bacteria lead to severe economic losses in potato production worldwide. To investigate the species composition of bacteria causing soft rot and black leg of potato in Norway and Poland, bacteria were isolated from potato tubers and stems. Forty-one Norwegian strains and 42 Polish strains that formed cavities on pectate medium were selected for potato tuber maceration assays and sequencing of three housekeeping genes (dnaX, icdA and mdh) for species identification and phylogenetic analysis. The distribution of the species causing soft rot and blackleg in Norway and Poland differed: we have demonstrated that mainly P. atrosepticum and P. c. subsp. carotovorum are the causal agents of soft rot and blackleg of potatoes in Norway, while P. wasabiae was identified as one of the most important soft rot pathogens in Poland. In contrast to the other European countries, D. solani seem not to be a major pathogen of potato in Norway and Poland. The Norwegian and Polish P. c. subsp. carotovorum and P. wasabiae strains did not cluster with type strains of the respective species in the phylogenetic analysis, which underlines the taxonomic complexity of the genus Pectobacterium. No correlation between the country of origin and clustering of the strains was observed. All strains tested in this study were able to macerate potato tissue. The ability to macerate potato tissue was significantly greater for the P. c. subsp. carotovorum and Dickeya spp., compared to P. atrosepticum and P. wasabiae.
Sammendrag
I denne rapporten presenteres resultater fra biologisk veiledningsprøving av ugrasmidler i grasmark, engsvingelfrøeng, vår- og høstkorn, såløk, gulrot under plast og på friland, knollselleri, pastinakk, rotpersille og bønne.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Den årlige skogovervåkingen viser at granas kronetilstand har bedret seg betraktelig på Vestlandet og i Midt-Norge etter de omfattende frosttørkeskadene der i 2013 og 2014. Furu hadde generelt lite skader. Det var mer skader på bjørk i 2016 enn i 2015, og både måler- og bjørkerustangrep økte i frekvens, men også abiotiske faktorer hadde stor betydning for bjørkas helsetilstand. Skadeomfanget var størst i Nord-Norge, der særlig gjentatte målerangrep over mange år utgjør et problem for bjørkeskogen. Askeskuddsjuke har i løpet av drøyt 10 år spredt seg gradvis gjennom mesteparten av askas utbredelsesområde i Norge. Overvåkingen viser at skadeutviklingen skjer fort, og særlig de yngste trærne har høy mortalitet. I Nord-Trøndelag og Oppland ble det registrert en økning i fangstverdiene av granbarkbiller i 2017, mens de øvrige fylkene opplevde en liten til moderat nedgang, mye på grunn av en kjølig og nedbørrik sommer.
Sammendrag
The impact of Delphinella shoot blight (Delphinella abietis) and Grovesiella canker (Grovesiella abieticola) on subalpine (Abies lasiocarpa) and corkbark fir (A. lasiocarpa var. arizonica) in a provenance trial in Idaho (ID) was evaluated in 2013. Both pathogens were previously reported from North America on fir species. D. abietis had been found on subalpine fir in USA, but not in ID, and G. abieticola on grand fir (Abies grandis) in ID, but not on subalpine or corkbark fir. D. abietis kills current-year needles and in severe cases buds and shoots, and G. abieticola results in dead shoots and branches and can eventually kill whole trees. Significant differences between provenances in susceptibility to D. abietis and G. abieticola were observed in the provenance trial in ID. In general, subalpine fir was more susceptible to both diseases than corkbark fir. In 2013, D. abietis was also found on subalpine fir in the Puget Sound area of Washington State and G. abieticola was seen on white fir (Abies concolor), but neither disease was detected in native stands of subalpine fir in Washington State. Morphological features of both fungi were described from samples collected in the provenance trial in ID in May 2016.
Forfattere
Alemayehu Getachew Assefa Alemayehu Chala Ingerd Skow Hofgaard May Bente Brurberg Michael Sulyok Anne Marte TronsmoSammendrag
The natural occurrence of fungi, mycotoxins and fungal metabolites was investigated in 100 samples of maize grains collected from south and southwestern Ethiopia in 2015. The maize samples were contaminated by Fusarium, Aspergillus and Penicillium species. Using liquid chromatography tandem mass spectrometry 127 secondary metabolites were analysed. Zearalenone was the most prevalent mycotoxin, occurring in about 96% of the samples. Zearalenone sulfate was the second most prevalent, present in 81% of the samples. Fumonisin B1 was detected in 70% of the samples with a mean level of 606 μg kg−1 in positive samples, while FB2, FB3 and FB4 were detected in 62%, 51% and 60% of the maize samples with mean levels of 202, 136 and 85 μg kg−1, respectively. Up to 8% of the samples were contaminated with aflatoxins, with a maximum level of aflatoxin B1 of 513 μg kg−1. Results were higher than earlier reports for maize from Ethiopia.
Forfattere
Igor A. Yakovlev Thomas Solvin Harald Kvaalen Arne Steffenrem Marcos Viejo Carl Gunnar FossdalSammendrag
Det er ikke registrert sammendrag