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
Dennis Eriksson Henrik Brinch-Pedersen Aakash Chawade Inger B. Holme Trine Hvoslef-Eide Anneli Ritala Teemu H. Teeri Tage ThorstensenAbstract
No abstract has been registered
Abstract
Based on soil temperature, snow depth and the grown cultivar's maximum attainable level of frost tolerance (LT50c), the FROSTOL model simulates development of frost tolerance (LT50) and winter damage, thereby enabling risk calculations for winter wheat survival. To explore the accuracy of this model, four winter wheat cultivars were sown in a field experiment in Uppsala, Sweden in 2013 and 2014. The LT50 was determined by tests of frost tolerance in November, and the cultivars’ LT50c was estimated. Further, recorded winter survival from 20 winter wheat field variety trials in Sweden and Norway was collected from two winter seasons with substantial winter damages. FROSTOL simulations were run for selected cultivars at each location. According to percentage of winter damage, the cultivar survival was classified as “survived,” “intermediate” or “killed.” Mean correspondence between recorded and simulated class of winter survival was 75% and 37% for the locations in Sweden and Norway, respectively. Stress factors that were not accounted for in FROSTOL might explain the poorer accuracy at the Norwegian locations. The accuracy was poorest for cultivars with intermediate LT50c levels. When low temperature was the main cause of damage, as at the Swedish locations, the model accuracy was satisfying.
Abstract
Acetophenones are phenolic metabolites of plant species. A metabolic route for the biosynthesis and release of 2 defence‐related hydroxyacetophenones in white spruce (Picea glauca) was recently proposed to involve 3 phases: (a) biosynthesis of the acetophenone aglycons catalysed by a currently unknown set of enzymes, (b) formation and accumulation of the corresponding glycosides catalysed by a glucosyltransferase, and (c) release of the aglycons catalysed by a glucosylhydrolase (PgβGLU‐1). We tested if this biosynthetic model is conserved across Pinaceae and land plant species. We assayed and surveyed the literature and sequence databases for possible patterns of the presence of the acetophenone aglycons piceol and pungenol and their glucosides, as well as sequences and expression of Pgβglu‐1 orthologues. In the Pinaceae, the 3 phases of the biosynthetic model are present and differences in expression of Pgβglu‐1 gene orthologues explain some of the interspecific variation in hydroxyacetophenones. The phylogenetic signal in the metabolite phenotypes was low across species of 6 plant divisions. Putative orthologues of PgβGLU‐1 do not form a monophyletic group in species producing hydroxyacetophenones. The biosynthetic model for acetophenones appears to be conserved across Pinaceae, whereas convergent evolution has led to the production of acetophenone glucosides across land plants.
Abstract
Plants are sessile organisms that lack a specialized immune system to cope with biotic and abiotic stress. Instead, plants have complex regulatory networks that determine the appropriate distribution of resources between the developmental and the defense programs. In the last years, epigenetic regulation of repeats and gene expression has evolved as an important player in the transcriptional regulation of stress‐related genes. Here, we review the current knowledge about how different stresses interact with different levels of epigenetic control of the genome. Moreover, we analyze the different examples of transgenerational epigenetic inheritance and connect them with the known features of genome epigenetic regulation. Although yet to be explored, the interplay between epigenetics and stress resistance seems to be a relevant and dynamic player of the interaction of plants with their environments.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Alemayehu Getachew Assefa Alemayehu Chala Ingerd Skow Hofgaard May Bente Brurberg Michael Sulyok Anne Marte TronsmoAbstract
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.
Abstract
submittedVersion
Abstract
No abstract has been registered
Abstract
The goal of this study was to assess the long-term effects of partial harvesting and supplementary soil scarification on the frequency of root and butt rot in managed uneven-sized Norway spruce stands. Frequency of rot and the population structure of the rot fungi were assessed on 1353 stumps after clear-cutting 21 years after a selection harvesting experiment. The initial experiment was comprised of three harvest strength (low, intermediate and high) of single-tree selection, removing approximately 25, 45 and 65% of the stand basal area. Uncut control plots were established at the same time. Supplementary soil scarification was applied in subplots within the single-tree selection plots, using a medium-sized excavator. After clear-cutting the stumps were analyzed with respect to rot caused by Heterobasidion parviporum, Armillaria spp., Stereum sanguinolentum as well as other rot fungi. Rot caused by Armillaria spp. was most common (8.6% of the stumps), while infection by H. parviporum (2.9%) or S. sanguinolentum (3.0%) was less frequent. The group “other rot” (5.4%) comprised 21 identified taxa, each occurring in 1–15 stumps. Significantly lower rot frequencies were found for the uncut control (16.3%) and intermediate harvest strength (15.7%), compared with low harvest strength (23.6%). A rot frequency of 21.0% was found in the high harvest strength. In two of three harvest strengths, the rot frequency was higher than for the uncut control. As the observed rot frequencies did not increase consistently with increasing harvest strength, the results do not completely support the initial expectations of increased rot after single-tree selection compared with the uncut control. However, since the probability of rot in individual stumps on plots treated with single-tree selection was significantly affected by the distance to the nearest strip road (H. parviporum) as well as dependent on the size of and distance to the nearest stump of trees cut during the experimental harvest (H. parviporum, S. sanguinolentum and total rot), it is evident that the single-tree selection harvesting was partially responsible for some of the observed rot. One of the selection criteria in the initial harvest was a sanitary removal of trees of poor vitality. Varying degrees of sanitation felling may therefore have offset the effects of new infections in wounds or spread of rot fungi through adjacent stumps. Supplementary soil scarification in small gaps of the residual stand had no significant effect on the frequency of rot, suggesting that such treatment may be used to facilitate regeneration in uneven-sized spruce stands on similar sites.