Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2018
Authors
Heidi Udnes Aamot Ingeborg Klingen Simon Edwards May Bente Brurberg Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa Gauslaa Ingerd Skow HofgaardAbstract
The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in crop residues, weeds, and soil sampled from a selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. The different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence of F. langsethiae in oat. Results show that F. langsethiae DNA may occur in the oat plant already before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. No Fusarium DNA was detected in soil samples. Of the arthropods that were associated with the collected oat plants, aphids and thrips species were dominating. Further details will be given at the meeting.
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Authors
Heidi Udnes Aamot Katherine Ann Gredvig Nielsen Shiori Koga Anne Kjersti Uhlen Ulrike Böcker Erik Lysøe Guro Brodal Ruth Dill-Macky Ingerd Skow HofgaardAbstract
The proportion of Norwegian wheat used for food has varied significantly during the recent decade, mainly because of the instability of factors that are essential to baking quality (i.e. protein content and gluten functionality). During the same period, serious contamination of Fusarium spp. and mycotoxins was observed in some grain lots [1, 2]. A project was established to generate greater knowledge of the interface between gluten functionality and effects of Fusarium species and other microorganisms on Norwegian wheat quality. Instances of severe degradation of gluten proteins that resulted in an almost complete loss of gluten functionality were observed in some lots of Norwegian wheat. The degradation of the gluten appeared to be caused by exogenous proteases. Metabarcoding of fungi and bacteria in these grain lots identified fungi within the Fusarium Head Blight complex, as well as one bacterial species, as candidate species for influencing gluten functionality. Some of these candidates were inoculated on wheat during flowering [3]. Analysis of baking quality of the flour from this experiment revealed a reduced proportion of un-extractable polymeric proteins (%UPP) and severe reductions in the gluten’s resistance to stretching (RMAX) in wheat flour from plants inoculated with Fusarium graminearum. Flour from wheat inoculated with Fusarium avenaceum was generally less infested, and showed minimal or no reduction in gluten functionality and %UPP compared to flour from the F. graminearum infested samples. Flour from wheat inoculated with Michrodochium majus is yet to be analysed. References 1. Koga, S., et al., Investigating environmental factors that cause extreme gluten quality deficiency in winter wheat (Triticum aestivum L.). Acta Agriculturae Scandinavica, Section B—Soil & Plant Science, 2016. 66(3): p. 237-246. 2. Hofgaard, I., et al., Associations between Fusarium species and mycotoxins in oats and spring wheat from farmers’ fields in Norway over a six-year period. World Mycotoxin Journal, 2016. 9(3): p. 365-378. 3. Nielsen, K.A.G., Effect of microorganisms on gluten quality in wheat., in Faculty of Biosciences. 2017, Norwegian University of Life Sciences: Ås.
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Authors
Jørn Henrik Sønstebø Mari Mette Tollefsrud Tor Myking Arne Steffenrem Anne Eskild Nilsen Øyvind Meland Edvardsen O. Ragnar Johnskås Yousry A. El-KassabyAbstract
Seed from orchards, established from breeding programs, often dominate the planting stock in economically important tree species, such as Norway spruce. The genetic diversity in seed orchards’ crops depends on effective population size which in turn is affected by many factors such as: number of parents in the orchard, seed orchards’ design, fecundity, and pollen contamination. Even though seed orchards’ seed is extensively used over large regions, very few studies have addressed how well their crops reflect the genetic diversity present in the regions where they are planted. Here we have investigated the genetic diversity (by means of 11 microsatellites) of two Norway spruce seed orchard populations with different number of parents (60 and 25) and compared this with seed crops collected in the semi natural forest and natural unmanaged populations. We found that the ratio between the effective population size (N e ) and actual number of parents (N) varied between 0.60 and 0.76 in the orchards’ seedlots. A reduction in genetic diversity (mainly allelic richness) was detected in a few seedlots, mainly where the number of parents was low. Our results also show that pollen contamination play an important role in maintaining the genetic diversity in orchards’ seedlots, particularly when the number of parents is low. The population genetic structure among seed orhcards and natural populations is shallow suggesting that re- generation with seed from current seed orchards will have limited effect on the overall genetic diversity.
Authors
C.A. Baroffio L. Sigsgaard E.J. Ahrenfeldt Anna-Karin Borg-Karlson Sara Andrea Bruun J.V. Cross M.T. Fountain D. Hall R. Mozuraitis B. Ralle Nina Trandem Atle WibeAbstract
Most horticultural crops are attacked by more than one insect pest. As broad-spectrum chemical control options are becoming increasingly restricted, there is a need to develop novel control methods. Semiochemical attrac- tants are available for three important horticultural pests, strawberry blossom weevil, Anthonomus rubi Herbst (Coleoptera: Curculionidae), European tarnished plant bug, Lygus rugulipennis Poppius (Hemiptera: Miridae) and raspberry beetle, Byturus tomentosus deGeer (Coleoptera: Byturidae). Traps targeting more than one pest species would be more practical and economical for both monitoring and mass trapping than traps for single-species. In this study we aimed to (1) improve the effectiveness of existing traps for insect pests in strawberry and raspberry crops by increasing catches of each species, and (2) test if attractants for two unrelated pest species could be combined to capture both in the same trap without decreasing the total catches. Field tests were carried out in four European countries and different combinations of semiochemicals were compared. A volatile from straw- berry flowers, 1,4 dimethoxybenzene (DMB), increased the attractiveness of the aggregation pheromone to both sexes of A. rubi. The host-plant volatile, phenylacetaldehyde (PAA), increased the attraction of female L. rugu- lipennis to the sex pheromone, and, in strawberry, there was some evidence that adding DMB increased catches further. Traps baited with the aggregation pheromone of A. rubi, DMB, the sex pheromone of L. rugulipennis and PAA attracted both target species to the same trap with no significant difference in catches compared to those single-species traps. In raspberry, catches in traps baited with a combination of A. rubi aggregation pheromone, DMB and the commercially available lure for B. tomentosus, based on raspberry flower volatiles, were similar to those in single-species traps. In both crops the efficiency of the traps still needs improvement, but the multi- species traps are adequate for monitoring and should not lead to confusion for the user as the target species are easy to distinguish from each other.
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Throughout history, man has strongly utilized and affected forest genetic resources in Europe. From an evolu-tionary perspective deforestation/fragmentation (→genetic drift), transfer of seeds and plants to new environ-ments (→mainly gene flow) and selective logging (→selection) are most relevant and have been particularlyaddressed in this review. In contrast to most conifers, broadleaved tree populations have been especially reducedby historic fragmentation, and consequently, the related genetic effects have been possibly more pronounced.Widespread wind-pollinated species with wind/animal dispersed seeds appear to be more resilient to frag-mentation than species with e.g. small geographic ranges and gravity dispersed seeds. In addition, naturallyfragmented populations in the range margins may be more vulnerable than central populations as conditions forgene flow are generally impaired in peripheral areas. Traits important for adaptation (e.g. bud burst, bud set) arecontrolled by many genes, and as a corollary of fragmentation such genes are lost at a low rate. Large scalecommercial translocation of seeds and plants for forestry purposes applies mostly to conifers and dates backabout two centuries. Although many translocations have been successful in a forestry perspective, exposure tonew selective regimes has sometimes challenged the adaptive limits of populations and caused setbacks or evendiebacks of populations, as well as influencing neighbouring populations with maladapted genes (e.g. Scots pine,maritime pine, larch). Many tree species have substantial plasticity in fitness-related traits, which is vital forsurvival and viability following translocations. Selective logging has been practiced in Europe over the last twocenturies and implies removal of superior trees with respect to growth and quality. Such traits are partly undergenetic control. Consequent removal of superior trees may therefore have negative effects on the remaining genepool, but this effect will also be counteracted by extensive gene flow. Although humans have strongly affectedEuropean forest trees over the last millennia, we argue that they are still resilient from an evolutionary perspective.