Network on Temperature Stress and Acclimation in Plants
During June we organized a network meeting in Umeå in conjunction with SSF-funded graduate course “Abiotic stress tolerance in plants”. This course hosted invited speakers from Scandinavia, Germany, the UK, Canada and the USA and it included student participants from Sweden and Finland, and the majority of students from the network. Throughout the Network also supported a number of exchange visits by both graduate students and post-doctoral researchers. These exchanges enabled the individual researchers to either learn new techniques or to conduct research, in collaboration with network partners, which they were not able to do in their home institutions. The research links opened by the network have covered topics ranging from micro-array analysis of the low temperature responses of deciduous tree species, to transgenic manipulation of Arabidopsis to assess the roles of cryoprotective compounds such as trehalose and sucrose on freezing tolerance. In addition to these molecular approaches, considerable effort has been extended to develop a detailed picture of the acclimation responses of core plant energy metabolism (both photosynthesis and respiration). It is hoped that in the future such detailed physiological and biochemical studies will be of great value in helping to interpret the wealth of data generated by the high through-put technology platforms such as the microarrays. Several cooperative manuscripts from within the network have now been published and additional manuscripts are in various stages of preparation. There were a number of exchanges by senior researchers to facilitate research planning and research grant writing. Several teacher exchanges are planned for .
Activities of the participating groups:
KVL, Denmark
Research activities:
Our research within the network is focused on isolation and characterization of mutants with changes in activity and regulation of primary carbohydrate metabolism, as this may influence cold acclimation due to changed accumulation of soluble sugars. We have isolated 3 homozygous mutants (SALK-lines, http://signal.salk.edu/) of Arabidopsis, which have T-DNA insertions in the gene encoding F2KP, the enzyme responsible for formation and degradation of Fructose-2,6-bisphosphate. The plants have been characterized with respect to localization of the insertion, enzyme activity, level of Fructose-2,6-bisphosphate, carbon partitioning, sugar and starch accumulation and response to a range of abiotic stresses. Two of the mutants have no detectable F2KP activity, whereas the third mutant in only partially reduced compared to wild type. The knock-out mutants accumulated 35% more sugars and 40% less starch than the wild type, when grown under optimal growth conditions. Under cold stress (5ºC, 10 days) the plants accumulate high levels of sugars (about 10 fold accumulation) but the difference between mutant and wild-type was retained. Thus, under cold stress the mutants accumulated 24% more sugars and 31% less starch than the wild type. Furthermore, we have isolated a number of other T-tagged SALK-mutants and homozygous lines of some of them. These mutants have insertions in genes encoding enzymes involved in hexose-phosphate metabolism. The lines remain to be characterized further.
People participating in NorFA related activities
Tom Hamborg Nielsen (Associate Professor)
Birgit Nielsen (Technician)
Renate Müller (Post doctoral researcher)
Expected number of participants during
2 persons:
Tom Hamborg Nielsen & Renate Müller
Risø, Denmark
Research activities:
The group has been trying to establish a technique for quantifying protein oxidation as a stress indicator. From May to November stem respiration measurements have been conducted at a forest site "Lille Bøgeskov" with 82 years old beech (Fagus sylvatica L.). The measurements have been analyzed in relation to temperature, time of year and position on the trunk.
People participating in NorFA related activities
Dr. Brian K. Kristensen, Plant Research Department, Risø National Laboratory
Prof. Ian M. Møller, Plant Research Department, Risø National Laboratory
Dr. Teis N. Mikkelsen, Plant Research Department, Risø National Laboratory
Expected number of participants during
3 persons:
Dr. Brian K. Kristensen, Prof. Ian M. Møller & Dr. Teis N. Mikkelsen
York, UK
Research activities:
In conjunction with the Estonian group, we are investigating whether light inhibits leaf respiration. Comparisons are being made of different methodologies used to measure R in the light. A paper will be submitted in on this subject. We will then further assess the extent to which R in the light acclimates to long-term changes in temperature. Together with Per Gardetröm’s group in Umeå, we have been investigating the effect of temperature on mitochondrial electron transport and redox status of the ubiquinone pool. We will continue analyzing the data and submit a paper to Plant Physiology in early . In collaboration with Vaughan Hurry’s group in Umeå, we are assessing whether the degree of thermal acclimation of photosynthesis and respiration can be predicted from leaf traits such as the ratio of leaf area to leaf mass. Several visits between the two labs are expected in , including an extended research visit by a post doc (C. Campbell). In collaboration with V Hurry and the Estonian group, we will continue to work on data looking at the effect of temperature on leaf gas exchange in Arabidopsis. Meetings will be required in to ensure that the papers are submitted by the end . In addition to these research interactions, Owen Atkin gave a seminar at Umeå in April and also acted as the external PhD examiner for Johan Baker-Åström.
People participating in NorFA related activities
Owen Atkin (Senior Lecturer)
PhD Students: Anna Armstrong, Liz Covey-Crump, Johanna Zaragoza-Castells, Priscilla Gan and Kelly Pescod
Undergraduate student: Kristen Wardlaw
Expected number of participants during
4 persions:
Owen Atkin, Anna Armstrong, Johanna Zaragoza-Castells & Catherine Campbell (post doc)
Harku, Estonia
Research activities:
In we have studied the short- (cold shock) and long-term (cold acclimation) effects of low temperature on photosynthetic gas exchange and carbon metabolism in transformants of Arabidopsis overexpressing sucrose phosphate synthase. It was found that in general the effects induced by low temperatures are similar in transformants to those in WT plants. Unlike the WT plants, in transformants sucrose synthesis was not stimulated and starch synthesis was not suppressed by low temperatures as the rate of sucrose synthesis in nonacclimated transformants was the same as in acclimated WT plants. In common experiments with research group from the University of York (O.Atkin, J.Zaragoza-Castells) different methods for the study of photosynthetic and respiratory gas exchange in leaves of Poa trivialis and Plantago lanceolata have been compared
People participating in NorFA related activities
Dr. Olav Keerberg (DSc)
Dr. Tiit Pärnik
Dr. Juta Viil
Graduate students: Hiie Ivanova, Peeter Talts, Hille Keerberg & Kaarin Laas
The same staff and students will continue with NorFA activities in .
Rovaniemi, Finland
Research activities:
Previous expression analysis in different birch tissues and under different conditions suggested that the omega-3 fatty acid desaturase gene reported up to now as cold-induced is in fact not related to the freezing resistance per se but in maintaining the functional integrity of chloroplast membrane at low temperature. To test this hypothesis, a short-term project was planned in Helsinki (Sept-Dec ) for transient expression of birch fatty acid desaturase genes in an Arabidopsis mutant lacking the omega-3 fatty acid desaturase activity. Such plant material will be used for the biochemical and enzymatic analysis of the birch fatty acid desaturase enzymes, and particularly to test the temperature effect. Seasonal changes in physiology and general activity of birch chlorenchyma is investigated by DNA chip analysis. First analysis of RNA chlorenchyma samples with a birch mini-DNA chip (around 800 cDNAs) are starting in autumn . A new collaboration was started in beginning of for the analysis of seasonal changes in photosystems composition in birch corticular chlorenchyma. The results will be compared with those obtained by Prof Öquist’s group in Umeå in the similar tissues in pine. Protein extraction procedure and analysis has been setup in Rovaniemi’s group for birch samples. Some material has already been tested in Umeå (Dmitry Sveshnikov, post-doc in Öquist’s group). Seasonal samples have now to be prepared in Rovaniemi and analyzed by western-blotting in Umeå.
People participating in NorFA related activities
Professor Marja-Liisa Sutinen
Dr. Françoise Martz
Expected participants for
3 persons:
Françoise Martz, Marja-Liisa Sutinen & Sari Kiviniemi (post-doc)
Helsinki, Finland
Research activities:
Topics for network collaboration: (i) The effect of trehalose on stress tolerance in plants and analysis of the tolerance mechanisms (with University of Skövde). (ii) Role of fatty acid desaturases in cold acclimation of birch and expression profiling of seasonal changes in birch clorenchyma.
People participating in NorFA related activities
Anne Leino female PhD student
Anne Kujanpää female PhD student
Elina Helenius female PhD student
Tuula Puhakainen female PhD student
Uma Balasubmariam female PhD student
Nina von Numers female PhD student
Kalle Ojala male PhD student
Claire Duhaze female post doc
Annikki Welling female post doc
Markku Aalto male post doc
Expected participants for
8 persons (5 PhD students)
Umeå, Sweden
Research activities:
Research activities in Umeå have touched on several different areas in , related to interactions with groups in the Denmark, the UK, Estonia and Finland. An extensive collaboration has developed between Umeå and the Biology Department at York University in relation to studies of photosynthetic and respiratory acclimation to low temperatures in the model plant Arabidopsis. In a new focus, we have started a broad ecologically based study of plant characteristics that determine species acclimation potential to fluctuating environments. The collaboration has also resulted in the first steps of developing new methods to measure the impact of temperature fluctuations on metabolite transport in the phloem. This collaboration with York has broadened our existing long-term research collaboration with the group in Harku to provide a detailed analysis of metabolite fluxes in source leaves of WT and transgenic lines of Arabidopsis. Ongoing collaboration with the group in Skövde has facilitated the production of several lines of high sucrose producing aspen that are now being analyzed for altered biomass production and in the coming year will be assessed for altered frost tolerance. These transgenics, together with the CBF transgenics, will be the focus of our aspen research and will enable us to compare the responses of herbaceous (Arabidopsis) and deciduous perennial (aspen) model species to low temperatures. In a new collaboration was established with the Finnish groups to investigate seasonal changes in photosynthetic activity in the phelloderm in birch and Scots pine, to determine its role in recovery and initiation of re-growth in the spring.
People participating in NorFA related activities
Professor Per Gardeström
Professor Gunnar Öquist
Associate Professor Vaughan Hurry
Post docs: Dmitry Sveshnikov, Estelle Goulas & Nathalie Druart
PhD students: Catherine Benedict, Maria Mathisen, Ola Nilssen, Johan Baker-Åström & Olivier Keech
Expected participants for
8 persons:
Per Gardeström, Vaughan Hurry, Gunnar Öquist, Catherine Benedict, Maria Mathisen, Oliver Keech, Catherine Campbell & Luke Hendrickson (post doc)
List of publications in from activities within the network
Atkin OK and Tjoelker MG () Thermal acclimation and the dynamic response of plant respiration to temperature. Trends in Plant Science 8: 343-351
Atkin OK, Bruhn D and Tjoelker MG () Plant respiration and temperature: mechanisms to ecosystems. In: Lambers, H. and Ribas-Carbó, M. (eds). Advances in Photosynthesis and Respiration. Vol. xx. Respiration and the Environment. pp. 000-000. Kluwer Academic Publishers, Dordrecht.
Hurry V, Igamberdiev AU, Keerberg O, Pärnik T, Atkin OK, Zaragoza-Castelle J, Gardeström P () Respiration in photosynthetic cells: gas exchange components, interactions with photorespiration and the operation of mitochondria in the light. In: Lambers, H. and Ribas-Carbó, M. (eds). Advances in Photosynthesis and Respiration. Vol. xx. Respiration and the Environment. pp. 000-000. Kluwer Academic Publishers, Dordrecht.
Ivanov AG, Sane P, Hurry V, Krol M, Svehnikov D, Huner NPA & Öquist G () Low-temperature modulation of the redox properties of the acceptor side of photosystem II: photoprotection through reaction centre quenching of excess energy. Physiologia Plantarum 119: 376-383.
Li C, Junttila O, Ernstsen A, Heino P & Palva ET () Photoperiodic control of growth, cold acclimation and dormancy in silver birch Betula pendula ecotypes. Physiologia Plantarum 117: 206-212.
Martz F, Kiviniemi S, Heino P, Palva To and Sutinen M-L () Genetic Control of Fatty Acid Desaturation during Cold Acclimation and De-acclimation of Birch.. Acta Horticulturae (in press).
Talts P, Pärnik T, Gardeström P & Keerberg O () Respiratory acclimation in Arabidopsis thaliana leaves at low temperature. Journal of Plant Physiology (in press).
Sane PV, Ivanov AG, Hurry V, Huner NPA & Öquist G () Changes in the redox potential of primary and secondary electron-accepting quinones in photosystem II confer increased resistance to photoinhibition in low-temperature-acclimated Arabidopsis. Plant Physiology, 132, .
Strand Å, Foyer CH, Gustafsson P, Gardeström P & Hurry, V. () Altering flux through the sucrose biosynthesis pathway in transgenic Arabidopsis thaliana modifies photosynthetic acclimation to low temperatures and the development of freezing tolerance. Plant Cell & Environment 26: 523-535.
Welling A, Rinne P, Viherä-Aarnio A, Kontunen-Soppela S, Heino P & Palva ET () Differential expression of two dehydrin genes during overwintering in birch (Betula pubescens Ehrh.) Journal of Experimental Botany (in press).
Papers submitted for review or in preparation:
Atkin OK, Bruhn D, Tjoelker MG and Hurry V () The response of plant respiration to temperature: making sense of variability in Q10 values and acclimation. Functional Plant Biology Submitted September
Benedict CB, Chang Y, Skinner JS, Davis J, Jeknic Z, Bhalerao R, Chen T & Hurry, V () Characterization of the CBF1 regulon in hybrid aspen using functional genomics (in prep.)
Covey-Crump EM, Bykova N, Gardeström P and Atkin OK () Temperature-dependent changes in ATP/ADP ratios, redox status of the ubiquinone pool and mitochondrial O2 uptake in potato leaves. Plant Physiology (to be submitted in Dec or Jan )
Druart N, Mathisen M, Strand Å, Gardeström P & Hurry V () Identification of novel cold stress and cold related genes in Arabidopsis leaves using cDNA-RDA coupled to cDNA microarray. (in prep)
Kristensen BK, Askerlund P, Bykova NV, Egsgaard H & Møller IM () Identification of oxidized mitochondrial proteins by immunoprecipitation and 2D-LC/MS/MS. Submitted for publication
Mathisen M, Trevanion S & Hurry V () Whole plant photosynthesis, carbon partitioning and export is affected by changes in the capacity for sucrose synthesis in transgenic Arabidopsis thaliana grown at low temperature. (in prep).
