Time filter

Source Type


Kovi M.R.,Norwegian University of Life Sciences | Fjellheim S.,Norwegian University of Life Sciences | Sandve S.R.,Norwegian University of Life Sciences | Larsen A.,Graminor AS | And 4 more authors.
Frontiers in Plant Science

Low temperature is one of the abiotic stresses seriously affecting the growth of perennial ryegrass (Lolium perenne L.), and freezing tolerance is a complex trait of major agronomical importance in northern and central Europe. Understanding the genetic control of freezing tolerance would aid in the development of cultivars of perennial ryegrass with improved adaptation to frost. The plant material investigated in this study was an experimental synthetic population derived from pair-crosses among five European perennial ryegrass genotypes, representing adaptations to a range of climatic conditions across Europe. A total number of 80 individuals (24 of High frost [HF]; 29 of Low frost [LF], and 27 of Unselected [US]) from the second generation of the two divergently selected populations and an unselected (US) control population were genotyped using 278 genome-wide SNPs derived from perennial ryegrass transcriptome sequences. Our studies investigated the genetic diversity among the three experimental populations by analysis of molecular variance and population structure, and determined that the HF and LF populations are very divergent after selection for freezing tolerance, whereas the HF and US populations are more similar. Linkage disequilibrium (LD) decay varied across the seven chromosomes and the conspicuous pattern of LD between the HF and LF population confirmed their divergence in freezing tolerance. Furthermore, two Fst outlier methods; finite island model (fdist) by LOSITAN and hierarchical structure model using ARLEQUIN, both detected six loci under directional selection. These outlier loci are most probably linked to genes involved in freezing tolerance, cold adaptation, and abiotic stress. These six candidate loci under directional selection for freezing tolerance might be potential marker resources for breeding perennial ryegrass cultivars with improved freezing tolerance. © 2015 Kovi, Fjellheim, Sandve, Larsen, Rudi, Asp, Kent and Rognli. Source

Rudi H.,Norwegian University of Life Sciences | Sandve S.R.,Norwegian University of Life Sciences | Opseth L.M.,Norwegian University of Life Sciences | Larsen A.,Graminor AS | Rognli O.A.,Norwegian University of Life Sciences
Plant Science

Studies of differential gene expression between cold acclimated (CA) and non-cold acclimated (NA) plants yield insight into how plants prepare for cold stress at the transcriptional level. Furthermore genes involved in the cold acclimation process are good candidate loci for genetic variation in frost tolerance and winter survival. In this study we combine different approaches to try to decode the genetics of cold acclimation and frost tolerance in meadow fescue (Festuca pratensis Huds). An EST library of cold acclimation responsive genes was established by suppression subtractive hybridization (SSH), and a microarray experiment was used to identify gene expression differences between high and low frost tolerance genotypes in response to cold acclimation. Many genes known to be involved in CA in other species were confirmed to be involved in CA in F. pratensis, however, 18% of the ESTs did not show significant homology to any database proteins. Seven genes were found to be differentially expressed (>2-fold) between high and low frost tolerance genotypes. Two of these genes, FpQM and FpTPT, represent interesting candidate genes for frost tolerance in perennial forage grasses. © 2010 Elsevier Ireland Ltd. Source

Bartos J.,Institute of Experimental Botany | Sandve S.R.,Norwegian University of Life Sciences | Kolliker R.,ART Agroscope Reckenholz Tanikon | Kopecky D.,Institute of Experimental Botany | And 7 more authors.
Theoretical and Applied Genetics

Species belonging to the Festuca-Lolium complex are important forage and turf species and as such, have been studied intensively. However, their out-crossing nature and limited availability of molecular markers make genetic studies difficult. Here, we report on saturation of F. pratensis and L. multiflorum genetic maps using Diversity Array Technology (DArT) markers and the DArTFest array. The 530 and 149 DArT markers were placed on genetic maps of L. multiflorum and F. pratensis, respectively, with overlap of 20 markers, which mapped in both species. The markers were sequenced and comparative sequence analysis was performed between L. multiflorum, rice and Brachypodium. The utility of the DArTFest array was then tested on a Festulolium population FuRs0357 in an integrated analysis using the DArT marker map positions to study associations between markers and freezing tolerance. Ninety six markers were significantly associated with freezing tolerance and five of these markers were genetically mapped to chromosomes 2, 4 and 7. Three genomic loci associated with freezing tolerance in the FuRs0357 population co-localized with chromosome segments and QTLs previously indentified to be associated with freezing tolerance. The present work clearly confirms the potential of the DArTFest array in genetic studies of the Festuca-Lolium complex. The annotated DArTFest array resources could accelerate further studies and improvement of desired traits in Festuca-Lolium species. © 2011 Springer-Verlag. Source

Uhlen A.K.,Norwegian University of Life Sciences | Uhlen A.K.,Nofima AS | Dieseth J.A.,Graminor AS | Koga S.,Norwegian University of Life Sciences | And 4 more authors.
Journal of Cereal Science

The aim of this study was to investigate variation in protein content and gluten viscoelastic properties in wheat genotypes grown in two mega-environments of contrasting climates: the southeast of Norway and Minnesota, USA. Twelve spring wheat varieties, nine from Norway and three HRS from Minnesota, were grown in field experiments at different locations in Norway and Minnesota during 2009-2011. Theresults showed higher protein content but lower TW and TKW when plants were grown in Minnesota, while the gluten quality measured as Rmax showed large variation between locations in both mega-environments. On average, Rmax of the samples grown in Minnesota was higher than those grown in Norway, but some locations in Norway had similar Rmax values to locations in Minnesota. The data showed inconsistent relationship between the temperature during grain filling and Rmax. Our results suggest that the weakening effect of low temperatures on gluten reported in this study are caused by other environmental factors that relate to low temperatures. The variety Berserk showed higher stability in Rmax as it obtained higher values in the environments in Norway that gave very weak gluten for other varieties. © 2015 Elsevier Ltd. Source

Alm V.,Norwegian University of Life Sciences | Alm V.,University of Oslo | Busso C.S.,Norwegian University of Life Sciences | Busso C.S.,Louisiana State University Health Sciences Center | And 5 more authors.
Theoretical and Applied Genetics

Quantitative trait loci (QTLs) for frost and drought tolerance, and winter survival in the field, were mapped in meadow fescue (Festuca pratensis Huds.) and compared with corresponding traits in Triticeae and rice to study co-location with putatively orthologous QTLs and known abiotic stress tolerance genes. The genomes of grass species are highly macrosyntenic; however, the Festuca/Lolium and Triticeae homoeologous chromosomes 4 and 5 show major structural differences that is especially interesting in comparative genomics of frost tolerance. The locations of two frost tolerance/winter survival QTLs on Festuca chromosome 5F correspond most likely to the Fr-A1 and Fr-A2 loci on wheat homoeologous group 5A chromosomes. A QTL for long-term drought tolerance on chromosome 3F (syntenic with rice 1) support evidence from introgression of Festuca genome segments onto homoeologous Lolium chromosomes (3L) that this genome region is an excellent source of tolerance towards drought stress. The coincident location of several stress tolerance QTL in Festuca with QTL and genes in Triticeae species, notably dehydrins, CBF transcription factors and vernalisation response genes indicate the action of structural or regulatory genes conserved across evolutionarily distant species. © 2011 Springer-Verlag. Source

Discover hidden collaborations