Plant Physiol.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on May 8, 2008; 10.1104/pp.108.117812

OPEN ACCESS ARTICLE
This Article
Free via Open Access: OA
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Google Scholar
Right arrow Articles by Welling, A.
Right arrow Articles by Palva, E. T.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Welling, A.
Right arrow Articles by Palva, E. T.
Agricola
Right arrow Articles by Welling, A.
Right arrow Articles by Palva, E. T.

Received February 17, 2008
Accepted April 29, 2008

Involvement of CBF Transcription Factors in Winter Hardiness in Birch

Annikki Welling and E. Tapio Palva *

Viikki Biocenter, Department of Biological and Environmental Sciences, Division of Plant Biology, P.O.Box 65 (Viikinkaari 1), FIN-00014 University of Helsinki, Finland; Viikki Biocenter, Department of Biological and Environmental Sciences, Division of Genetics, P.O.Box 56 (Viikinkaari 5), FIN-00014 University of Helsinki, Finland

* Corresponding author; email: tapio.palva{at}helsinki.fi.

Cold acclimation of plants involves extensive reprogramming of gene expression. In Arabidopsis three cold-inducible transcriptional activators designated CBF1-3/DREB1a-c have been shown to play an important regulatory role in this acclimation process. Similarly to Arabidopsis, boreal zone trees can increase their freezing tolerance (FT) in response to low temperature (LT) during the growing season. However, maximal FT of these trees requires short daylength (SD) induced dormancy development followed by exposure to both low and freezing temperatures. To elucidate the molecular basis of FT in overwintering trees, we characterized the role of birch (Betula pendula Roth) CBF transcription factors in the cold acclimation process. We identified four putative CBF orthologs in a birch EST collection designated BpCBF1-4. Ectopic expression of birch CBFs in Arabidopsis resulted in constitutive expression of endogenous CBF target genes and increased freezing tolerance of non-acclimated transgenic plants. In addition, these plants showed stunted growth and delayed flowering, typical features for CBF overexpressing plants. Expression analysis in birch showed that BpCBF1-4 are LT responsive but differentially regulated in dormant and growing plants, the expression being delayed in dormant tissues. Freeze-thaw treatment, simulating winter-time conditions in nature, resulted in strong induction of BpCBF genes during thawing, followed by induction of a CBF target gene BpLTI36. These results suggest that in addition to their role in cold acclimation during the growing season birch CBFs appear to contribute to control of winter hardiness in birch.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2008 by the American Society of Plant Biologists