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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 .