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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.

2026

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Abstract The use of Saccharomyces cerevisiae to ferment alcoholic beverages is an ancient tradition, with genetic evidence indicating origins in Neolithic Asia, although the domestication process of the species is not fully understood. Kveik is a group of traditional yeasts used in farmhouse brewing in western Norway preserved through generations of rural brewing practice. While recent studies have highlighted the distinctiveness of kveik, its precise phylogenetic position, genetic diversity, and domestication history remain unclear. We performed whole-genome sequencing on 64 isolates from 25 traditional brewing cultures from Western Norway selected using cultural heritage criteria and generated telomere-to-telomere assemblies for selected strains. Phylogenomic and population genetic analyses reveal that kveik strains form a paraphyletic and early-diverging group with respect to other domesticated S. cerevisiae strains. Most strains exhibit low diversity among isolates from the same brewing culture, strong geographic clustering, and little evidence of gene flow or admixture. Mitochondrial genomes and Ty1 retrotransposon profiles corroborate this distinct lineage history. We further show that previously reported signals of gene flow between kveik and Asian fermentation strains are likely artifacts caused by population structure and selection. Divergence time estimates suggest that the common ancestor of beer, kveik, and other liquid-phase fermenting strains originated from ancestral populations 4,000 to 8,000 years ago. Our genomic resource sheds light on yeast evolution and domestication. Kveik likely comprises some of the oldest domesticated lineages in continuous use until today, connecting intangible cultural heritage to an early genetic origin.

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Blue rings (BRs) are wood anatomy anomalies that present great potential in identifying cold spells during the growing season. In this study, we investigated the effect of temperature anomalies on the occurrence of two types of BR in Pinus sylvestris at its northern distribution limit in Norway. Of the 3508 individual tree rings from 1727 to 2022 analysed, we identified 206 BRs from a span of 85 years, the oldest formed in 1730. We distinguished two types of BR: Type A with normal earlywood and latewood ending with a thin blue layer; and Type B with the entire latewood zone replaced by earlywood-like tracheids. Our results demonstrate that the two types have a common climatic trigger – a cool spring and autumn. However, Type A is more linked to tree-ring width, whereas Type B is associated more closely with tree ontogeny and local environmental constraints. Although we observed the formation of BRs even in old trees, we found that they formed more frequently in young specimens. We showed that while the short-term cyclical drivers of Type A remained persistent, the climatic or environmental drivers associated with Type B gradually diminished under climate change. Our study demonstrates that the differentiation of BRs into types can contribute to a better understanding of their driving factors; however, detailed intra-annual phenological and xylogenetic monitoring will be crucial to achieve further insights.

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Abstract Peatlands drained for agriculture and other uses release substantial carbon dioxide. Many countries estimate these emissions using the 2014 IPCC Tier 1 emission factors. Here we calibrated an ecosystem model with data from two cultivated peatland sites in Norway and simulate carbon dioxide emissions at 50 sites nationwide for 2001–2022. Model results showed that carbon dioxide emissions were strongly controlled by water table depth and aligned well with observations from other European peatlands of similar climate zones. Crucially, the Tier 1 emission factor matched our simulations only under very deep water tables (< –0.7 m), but overestimated emissions by 31–88% when water levels ranged from –0.7 m to –0.3 m. This indicates that Tier 1 methods may overstate emissions from cultivated peatlands in cool temperate and boreal regions, inflating estimates of mitigation potential. Tier 2 or 3 approaches can reduce uncertainty but require more field data.

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Background: Pesticides are used in greenhouse cultivation to control fungi and pests and to shape plant growth. This influences microbial communities and may increase the selective pressure for resistant species development. Antimicrobial resistance (AMR) is a growing global health challenge, and while AMR dispersal through soil and water is well studied, the role of bioaerosols as AMR vectors remains insufficiently explored. Objectives: To explore the link between chemical pesticide and the prevalence of AMR genes in aerosols from greenhouses using pesticides and those not using them. Methods: Forty-nine fullshift personal samples of inhalable dust were collected in eight greenhouses from 2021 and 2024. Five greenhouses used chemical pesticides and three did not. DNA was extracted and screened for the presence of 45 clinically relevant AMR genes using HT-qPCR. Results: Twenty of the 45 screened genes were detected. Greenhouses using pesticides showed significantly higher AMR gene levels than those not using chemicals. Several genes, particularly β-lactam and tetracycline resistance genes, occurred in high concentrations, including extreme values exceeding 60,000 gene copies/m³. This suggest that pesticide-using greenhouses may represent a greater risk for AMR dispersal. In contrast, greenhouses without chemical pesticide showed lower and more stable AMR gene levels. Factors other than pesticide application may also contribute, such as import of treated plants, soil and fertilizer materials, plant types or individual workers. Further research is needed to assess the health risks for greenhouse workers and to support the development of effective strategies for preventing and controlling AMR spread.

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Small, superficial rot spots occurring around lenticels postharvest on apple in Norway have not been identified but were assumed to be underdeveloped Neofabraea lesions. Fungal isolation from such spots on fruit from the 2022 season revealed both Neofabraea perennans and Ramularia spp., identified by B-tubulin and ITS sequencing, respectively. In the 2023 season, isolations were made from fruit with spots resembling dry lenticel spot caused by Ramularia mali. The aim of this study was to identify the Ramularia species associated with the postharvest fruit spots in Norway. Multiple gene regions of five Norwegian isolates (E20, E21 from 2022; 13,15 and 18 from 2023) and three reference isolates, R. mali, R. eucalypti, and R. collo-cygni, were sequenced and used for phylogenetic analysis. The Norwegian isolates were distinct from the included reference isolates, but clustered with other Ramularia species. Isolates 13, 18 and E21 clustered with Ramularia vizellae, while isolates 15 and E20 were most closely related to Ramularia phacae-frigidae. Isolate E20 was sequenced using the Oxford Nanopore Technologies MinION platform. Pathogenicity was assessed in a field inoculation study using isolate E21, resulting in typical spot development on inoculated fruit. Ramularia vizellae has previously been reported from dead apple leaf litter and other woody hosts in the Netherlands and Iran, while R. phacae-frigidae was originally described from Phaca frigida in Switzerland. Neither species has previously been reported in association with apple fruit spotting. While Ramularia mali has caused outbreaks on apple in several European countries, recent studies hypothesize that the symptoms may be caused by a species complex with regional variation. The present results identify candidate species contributing to this complex in Norway and highlight the need for further studies to improve species delimitation and pathogenicity.

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Accurate species identification is essential for conserving and managing plants that provide important ecosystem services and have ethnobotanical value. The Greyia tree genus ( G. sutherlandii , G. radlkoferi and G. flanaganii ) is endemic to South Africa and Eswatini, and certain genotypes have medicinal value for treating skin hyper‐pigmentation. However, distinguishing among species is difficult because of overlapping phenotypes and the limited resolution of standard DNA barcodes. To overcome these limitations, a robust molecular identification assay was developed using a two‐phase strategy. First, de novo SNP discovery using 3RAD sequencing identified 47,726 genome‐wide SNPs from two to three plants sampled from each species' core geographic range: G. radlkoferi in northern Limpopo, G. sutherlandii in eastern KwaZulu‐Natal, and G. flanaganii in the south‐eastern Eastern Cape. Principal component analysis and coancestry matrices revealed three discrete genetic clusters, supporting the recognition of the three species. Selecting a set of 200 SNPs with intermediate Fst values (0.2–0.5) resulted in optimal separation of the three clusters. This led to the final selection of a 23‐SNP panel that included five informative barcoding loci (ITS, trnL‐F , matK ). Second, the 23 SNPs were converted into allele‐specific fluorescent PCR assays (SNP Type) for genotyping on the BioMark HD platform. The panel was validated using genomic DNA from 17 individuals from the 3RAD population groups and successfully differentiated all three species. It was then applied to 73 trees sampled across a 1000‐km transect from the Eastern Cape to Limpopo. Genetic clustering (PCA, UPGMA and ADMIXTURE) assigned each tree to one of three species‐level groups matching their expected ranges. In a practical case study, the assay also identified the species origin of 33 Greyia trees of unknown provenance from production orchards. This study provides an efficient SNP‐based tool for accurate species identification, supporting conservation planning and the sustainable management of Greyia populations.

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Did you know that stairstep moss can be used as a sampler for air pollution? Researchers at NILU have collected this kind of moss on several occasions and examined it for metals and other pollutants.