Publications by authors named "Trygve D Kjellsen"

6 Publications

  • Page 1 of 1

Extreme low temperature tolerance in woody plants.

Front Plant Sci 2015 19;6:884. Epub 2015 Oct 19.

Department of Biology, Norwegian University of Science and Technology Trondheim, Norway.

Woody plants in boreal to arctic environments and high mountains survive prolonged exposure to temperatures below -40°C and minimum temperatures below -60°C, and laboratory tests show that many of these species can also survive immersion in liquid nitrogen at -196°C. Studies of biochemical changes that occur during acclimation, including recent proteomic and metabolomic studies, have identified changes in carbohydrate and compatible solute concentrations, membrane lipid composition, and proteins, notably dehydrins, that may have important roles in survival at extreme low temperature (ELT). Consideration of the biophysical mechanisms of membrane stress and strain lead to the following hypotheses for cellular and molecular mechanisms of survival at ELT: (1) Changes in lipid composition stabilize membranes at temperatures above the lipid phase transition temperature (-20 to -30°C), preventing phase changes that result in irreversible injury. (2) High concentrations of oligosaccharides promote vitrification or high viscosity in the cytoplasm in freeze-dehydrated cells, which would prevent deleterious interactions between membranes. (3) Dehydrins bind membranes and further promote vitrification or act stearically to prevent membrane-membrane interactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2015.00884DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4609829PMC
November 2015

Metabolomic analysis of extreme freezing tolerance in Siberian spruce (Picea obovata).

New Phytol 2014 Nov 20;204(3):545-555. Epub 2014 Aug 20.

Department of Chemistry, Umeå University, SE-90187, Umeå, Sweden.

Siberian spruce (Picea obovata) is one of several boreal conifer species that can survive at extremely low temperatures (ELTs). When fully acclimated, its tissues can survive immersion in liquid nitrogen. Relatively little is known about the biochemical and biophysical strategies of ELT survival. We profiled needle metabolites using gas chromatography coupled with mass spectrometry (GC-MS) to explore the metabolic changes that occur during cold acclimation caused by natural temperature fluctuations. In total, 223 metabolites accumulated and 52 were depleted in fully acclimated needles compared with pre-acclimation needles. The metabolite profiles were found to develop in four distinct phases, which are referred to as pre-acclimation, early acclimation, late acclimation and fully acclimated. Metabolite changes associated with carbohydrate and lipid metabolism were observed, including changes associated with increased raffinose family oligosaccharide synthesis and accumulation, accumulation of sugar acids and sugar alcohols, desaturation of fatty acids, and accumulation of digalactosylglycerol. We also observed the accumulation of protein and nonprotein amino acids and polyamines that may act as compatible solutes or cryoprotectants. These results provide new insight into the mechanisms of freezing tolerance development at the metabolite level and highlight their importance in rapid acclimation to ELT in P. obovata.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/nph.12950DOI Listing
November 2014

Proteomics of extreme freezing tolerance in Siberian spruce (Picea obovata).

J Proteomics 2010 Mar 11;73(5):965-75. Epub 2010 Jan 11.

Department of Biology Norwegian University of Science and Technology, N-7491 Trondheim, Norway.

Differential expression of proteins in needles of the extreme freeze tolerant conifer Picea obovata during September, October and November was analyzed using DIGE technology and multivariate analysis. More than 1200 spots were detected, and the abundance of 252 of these spots was significantly altered during the course of acclimation. The 252 spots were clustered into five distinct expression profiles. Among the protein spots showing differential expression, 43 were identified by MALDI-TOF/TOF and twelve of them matched proteins associated with various biotic and abiotic stress responses in other plants. Dehydrins, Hsp70s, AAA(+) ATPases, lipocalin, cyclophilins, glycine-rich protein (GNP) and several reactive oxygen intermediate scavenging proteins showed increased accumulation levels from September to November. The expression profiles and putative role of the identified proteins during acclimation and freezing tolerance are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jprot.2009.12.010DOI Listing
March 2010

Dynamics of low-temperature acclimation in temperate and boreal conifer foliage in a mild winter climate.

Tree Physiol 2008 Sep;28(9):1365-74

Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway.

To provide baseline data for physiological studies of extreme low-temperature (LT) tolerance in boreal conifers, we profiled LT stress responses, liquid nitrogen (LN(2))-quench tolerance, and sugar concentrations in foliage of boreal-temperate species pairs in the genera Abies, Picea and Pinus, growing in an arboretum in a temperate oceanic climate from August 2006 through April 2007. The boreal species acclimated more rapidly and deeply than the temperate species, acquiring LN(2)-quench tolerance by late November, despite unusually warm conditions throughout the autumn and early winter. Maximum LT tolerance in the temperate species was in the -25 to -35 degrees C range, and was reached only after a period of freezing temperatures in late January and February. During LT acclimation in the temperate species, sigmoid temperature-relative electrolyte leakage (REL) curves shifted toward lower temperatures, whereas in boreal species there was both a temperature shift and a lowering of the maximum REL until it fell below a threshold associated with irreversible injury. These differences may reflect differences in mechanisms of LT acclimation and LT tolerance. The concentrations of total and individual sugars did not show a clear pattern that could differentiate the boreal and temperate groups. Raffinose and, in three of the six species, stachyose showed the closest association with LT tolerance. Sugar concentrations, principally sucrose, decreased during mild weather, perhaps because of respiratory losses or phloem export, and increased after periods of freezing temperatures. Low-temperature acclimation in boreal species appears to follow a rigid program that may affect their ability to avoid excessive respiratory losses in the event of continued climate warming in boreal regions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/treephys/28.9.1365DOI Listing
September 2008

A case study from the interaction of strawberry and Botrytis cinerea highlights the benefits of comonitoring both partners at genomic and mRNA level.

New Phytol 2005 Nov;168(2):465-74

Sør-Trøndelag University College, Faculty of Food Science and Medical Technology, Trondheim, Norway.

Strawberry Fragaria x ananassa (cv. Korona) was inoculated with Botrytis cinerea by dipping berries in a conidial suspension. Colonization by the pathogen was monitored using real-time PCR, ELISA and ergosterol assays, the first showing the highest sensitivity. The expression of pathogen beta-tubulin and six polygalacturonases (Bcpg1-6) and three host defence genes (polygalacturonase-inhibiting protein (FaPGIP) and two class II chitinases) were monitored using real-time RT-PCR. The maximum transcript levels of the host defence genes occurred at 16 h postinoculation (hpi) at the presumed initial penetration stage. The unique transcript profile of Bcpg2 over the 96-h incubation time and its high transcript levels relative to those of the other Bcpgs at 8-24 hpi suggest that the gene has a specific role in the penetration stage. Bcpg1 was expressed constitutively at a relatively high level in actively growing mycelia throughout the experimental period. Comparison of the transcript profiles indicated that Bcpg1 and Bcpg3-6 were coordinately regulated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1469-8137.2005.01526.xDOI Listing
November 2005

A gene encoding a polygalacturonase-inhibiting protein (PGIP) shows developmental regulation and pathogen-induced expression in strawberry.

New Phytol 2004 Jul;163(1):99-110

Plantebiosenteret, Department of Biology, NTNU, 7491 Trondheim, Norway.

•  Polygalacturonase-inhibiting proteins (PGIPs) have been demonstrated to play a role in host defence in several plants. •  The PGIP now cloned from strawberry (Fragaria × ananassa) showed a high degree of homology to other fruit PGIPs. The gene expression of strawberry PGIP was monitored in healthy leaves, flowers and fruit at different maturity stages. PGIP transcript levels were also analysed following fruit inoculation with the fungal pathogen Botrytis cinerea in strawberry cultivars displaying variation in susceptibility. •  Healthy mature berries showed the highest constitutive PGIP gene expression levels compared with leaves, flowers and immature fruit, indicating that the gene is developmentally regulated. Among the cultivars studied ('Elsanta', 'Korona', 'Polka', 'Senga sengana', 'Tenira'), 'Polka' had the highest constitutive expression level of PGIP. After inoculation with B. cinerea, all five cultivars displayed a significant induction of PGIP gene expression, but the differences between them were not statistically significant. •  The high induction of the PGIP gene after inoculation with B. cinerea indicates that PGIP has a role in defence of strawberry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1469-8137.2004.01088.xDOI Listing
July 2004