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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.

2012

Abstract

Freezing damage is a crucial factor in the cultivation of perennial crops. Overwintering plants acclimate to decreasing temperatures in their environment and thus, prevent freezing damage of plant tissue. To assess transcriptional and metabolic changes in meristematic tissue (crowns) of octoploid strawberry (Fragaria × ananassa Duch.), acclimation experiments were carried out at above-zero temperature (2 °C) using three cultivars with contrasting cold tolerance: ‘Elsanta’ < ‘Frida’ < ‘Jonsok’. Crowns were sampled after 1 day (d), 2d, 2 weeks (w) and 6w in order to detect short- and long-term metabolic shifts. GC/MS-based metabolite profiling revealed more than 140 metabolites (identified structures, not-annotated mass spectral tags, and unidentified metabolites). Transcriptional changes were assessed at two time points (2d and 6w) using a customized Fragaria microarray chip developed as a joint collaboration between Graminor Breeding Ltd. and NTNU. A total of 4061 differentially regulated transcripts (unique 60-mer probes) with a p-value≤0.05 were detected in all hybridizations. Microarray analysis revealed the up-regulation of ~100 cold-responsive transcripts (TFs and dehydrins), also including enzymes involved in starch breakdown and raffinose biosynthesis. Gene-metabolite correlation analysis revealed strong connectivity in components of Krebs-cycle (citric and succinic acid), amino acids (isoleucine, aspartic acid, glutamic acid, valine and phenylalanine) and the raffinose pathway. Metabolite levels of hexoses (fructose and glucose), trisaccharides (raffinose), amino acids (aspartic acid, alanine and serine), phenols (gallic acid) and several polyphenols still increased during long-term acclimation phase. Varietal differences could be clearly explained by Venn diagrams: frost-tolerant ‘Jonsok’ showed least individual up- or down-regulated transcripts (2 d), and least commonly shared transcripts with frost-sensitive ‘Elsanta’ (2d and 6w). Further multivariate statistics and network analyses underscored genotype-dependent cold responses, and might further guide in the identification of frost-tolerant vs. sensitive plants in diverse Fragaria accessions or cross-breeding populations .

To document

Abstract

In terrestrial ecosystems, fungi are the major agents of decomposition processes and nutrient cycling and of plant nutrient uptake. Hence, they have a vital impact on ecosystem processes and the terrestrial carbon cycle. Changes in productivity and phenology of fungal fruit bodies can give clues to changes in fungal activity, but understanding these changes in relation to a changing climate is a pending challenge among ecologists. Here we report on phenological changes in fungal fruiting in Europe over the past four decades. Analyses of 746,297 dated and geo-referenced mushroom records of 486 autumnal fruiting species from Austria, Norway, Switzerland, and the United Kingdom revealed a widening of the annual fruiting season in all countries during the period 1970–2007. The mean annual day of fruiting has become later in all countries. However, the interspecific variation in phenological responses was high. Most species moved toward a later ending of their annual fruiting period, a trend that was particularly strong in the United Kingdom, which may reflect regional variation in climate change and its effects. Fruiting of both saprotrophic and mycorrhizal fungi now continues later in the year, but mycorrhizal fungi generally have a more compressed season than saprotrophs. This difference is probably due to the fruiting of mycorrhizal fungi partly depending on cues from the host plant. Extension of the European fungal fruiting season parallels an extended vegetation season in Europe. Changes in fruiting phenology imply changes in mycelia activity, with implications for ecosystem function.