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.
2024
Authors
Anastasia Georgantzopoulou Sebastian Kühr Ralph Kaegi Mark Rehkämper Ralph A. Sperling Karl Andreas Jensen Ana Catarina Almeida Claire CoutrisAbstract
No abstract has been registered
Authors
Tomasz Leszek WoznickiAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Heathlands are extensive systems often dominated by slow-growing and long-lived woody plants. These systems require longer-term studies to capture if and how they are changing over time. In 2020, we resurveyed species richness and cover of vascular plant communities in 139 heathlands along the coastline of northern Fennoscandia, first surveyed during 1965–1975. The first survey included six heathland types, each with dominance – a cover of 25% or more – of the dwarf shrubs Calluna vulgaris, Kalmia procumbens, Betula nana, Vaccinium myrtillus and Empetrum nigrum. The two latter heathland types made up 29% and 48%, respectively, of all heathlands. In addition to the dominant dwarf shrubs giving their names to the heathland types, a few other species qualified as dominant. In the resurvey, all the heathland types had E. nigrum as the single dominant species, except for the heathland formerly dominated by B. nana. Most other species had low cover both at the time of the original survey and the resurvey. Also, the heathland types were species poor at the time of the original survey, with an average of eight vascular plant species per 4 m2 and were found equally species poor in the resurvey. Species richness differed between heathland types only at the time of the original survey, and the ratio of species exchange between the two surveys was negatively related to the original cover of E. nigrum. Here we provide a half-century perspective on vegetation change, during which several heathland types in northern Fennoscandia have changed to Empetrum heathlands, reducing the diversity of heathland types across the Boreal to Arctic landscape. As a native plant, E. nigrum cannot be considered invasive, but its allelopathic capacity has likely already modified these heathland ecosystems and will continue to do so, reducing ecosystem multifunctionality across the region.
Authors
James A. Price Kelsey Hunt Newton Nyagah Calvince Orage Onesmus Mwaura Solveig Haukeland Danny Coyne John T. JonesAbstract
Potato production in East Africa is seriously impacted by the potato cyst nematode (PCN), Globodera rostochiensis, where it has been recorded in at least three countries. In Kenya, it is widespread in all major potato-growing regions, often at very high densities. Consecutive cropping of potato on the same land and a sub-tropical climate have influenced PCN biology. For example, unusually large cysts have been regularly recovered. We have analysed the biological properties of these ‘giant cysts’. The giant cysts contained more eggs than those recovered from UK fields. Egg size did not differ from UK populations and there was no difference in overall lipid content or lipid profile in J2 from giant cysts, compared to control samples. The nematodes in giant cysts were also genetically indistinguishable from any other G. rostochiensis sampled. When grown under UK glasshouse conditions, the offspring of nematodes from giant cysts were no different in size from those grown from control cysts, indicating that gigantism is not a heritable trait and may simply reflect favourable conditions for PCN under Kenyan farming systems. To date, all the PCN tested from Kenya, including those from giant cysts, are avirulent on potato cultivars containing the H1 resistance gene
Authors
Hilary Edema Muhammad Furqan Ashraf Amos Samkumar Laura Elina Jaakola Katja Hannele KarppinenAbstract
Cellulose is a major renewable resource for a wide variety of sustainable industrial products. However, for its utilization, finding new efficient enzymes for plant cell wall depolymerization is crucial. In addition to microbial sources, cellulases also exist in plants, however, are less studied. Fleshy fruit ripening includes enzymatic cell wall hydrolysis, leading to tissue softening. Therefore, bilberry (Vaccinium myrtillus L.), which produces small fruits that undergo extensive and rapid softening, was selected to explore cellulases of plant origin. We identified 20 glycoside hydrolase family 9 (GH9) cellulases from a recently sequenced bilberry genome, including four of which showed fruit ripening-specific expression and could be associated with fruit softening based on phylogenetic, transcriptomic and gene expression analyses. These four cellulases were secreted enzymes: two B-types and two C-types with a carbohydrate binding module 49. For functional characterization, these four cellulases were expressed in Pichia pastoris. All recombinant enzymes demonstrated glucanase activity toward cellulose and hemicellulose substrates. Particularly, VmGH9C1 demonstrated high activity and ability to degrade cellulose, xyloglucan, and glucomannan. In addition, all the enzymes retained activity under wide pH (6–10) and temperature ranges (optimum 70 °C), revealing the potential applications of plant GH9 cellulases in the industrial bioprocessing of lignocellulose.
Authors
Muhammad Furqan Ashraf Amos Samkumar Rajan Premkumar Laura Elina Jaakola Katja Hannele KarppinenAbstract
No abstract has been registered
Authors
Muhammad Furqan Ashraf Amos Samkumar Rajan Premkumar Teemu Teeri Laura Elina Jaakola Katja Hannele KarppinenAbstract
Fruit ripening including softening process is a vital developmental phase for gaining appealing fruit flavour, colour and texture. Bilberry (Vaccinium myrtillus L.) fruits are well-known for their health-promoting effects. However, bilberry fruits have a short shelf-life indicating a high activity of cell wall-degrading enzymes (CWDEs) [1] that may degrade fruit pectins leading to fruit softening. Pectate lyase (PL: EC 4.2.2.2) are recognized as pectin modifying enzymes, which are capable of cleaving glycosidic bonds through a β-elimination mechanism between galacturonosyl residues and result in loosening the cell wall during the cell separation and expansion growth phase in plants. In this study, a total of 25 PL genes from bilberry genome were identified and their expression was analyzed from transcriptome data of ripening bilberries. The genes associated in ripening fruits were further studied by qRT-PCR analysis which indicated that expressions of VmPL02, VmPL06, VmPL07, and VmPL24 peaked at ripening fruit and were also induced by ABA treatment. Further, the expression of these VmPL genes was induced by red light treatment. Verification of PL activity by recombinant PL proteins produced in yeast are ongoing. To conclude, our study indicated a role for four PL genes in bilberry fruit softening. Their induction by ABA and red light indicates them to be controlled by ABA-regulatory pathway [2], which is the key ripening controller in bilberry [1]. Thus, these genes may be responsible for the short self-life of bilberry fruit by attending in pectin degradation in fruit flesh. References [1] Karppinen K, Tegelberg P, Häggman H, Jaakola L: Abscisic acid regulates anthocyanin biosynthesis and gene expression associated with cell wall modification in ripening bilberry (Vaccinium myrtillus L.) fruits. Frontiers in Plant Science 2018, 9:1259. [2] Samkumar A, Jones D, Karppinen K, Dare AP, Sipari N, Espley RV, Martinussen I, Jaakola L: Red and blue light treatments of ripening bilberry fruits reveal differences in signalling through abscisic acid‐regulated anthocyanin biosynthesis. Plant, Cell & Environment 2021, 44(10):3227-3245
Authors
Katja Hannele Karppinen Muhammad Furqan Ashraf Hilary Edema Laura Elina Jaakola Amos Samkumar Rajan PremkumarAbstract
No abstract has been registered
Authors
Ingunn Øvsthus Mitja Martelanc Alen Albreht Tatjana Radovanović Vukajlović Urban Česnik Branka Mozetič VodopivecAbstract
Our investigation delves into the previously uncharted territory of cider composition from Norway. This study aimed to obtain an overview of the qualitative and quantitative compositions of general chemical parameters, polyphenols (individual and total expressed as gallic acids equivalents), selected esters, and selected C6-alcohols in ciders with the PDO label Cider from Hardanger. In total, 45 juice and cider samples from the fermentation process were collected from 10 cider producers in Hardanger in 2019, 2020, and 2021. Individual sugars, acids, ethanol, and 13 individual phenols were quantified using HPLC-UV/RI. Seven ethyl esters of fatty acids, four ethyl esters of branched fatty acids, ten acetate esters, two ethyl esters of hydroxycinnamic acids, and four C6-alcohols were quantified using HS-SPME-GC-MS. For samples of single cultivars (‘Aroma’, ‘Discovery’, ‘Gravenstein’, and ‘Summerred’), the sum of the measured individual polyphenols in the samples ranges, on average, from 79 to 289 mg L−1 (the lowest for ‘Summerred’ and highest for ‘Discovery’ and ‘Gravenstein’). Chlorogenic acid was the most abundant polyphenol in all samples. Ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl isobutyrate, ethyl 2-methylbutyrate, isoamyl acetate, and hexanol were present at concentrations above the odour threshold and contributed to the fruity flavour of the Cider from Hardanger.