Plant & Animal Genomes XVI Conference

January 12-16, 2008
Town & Country Convention Center
San Diego, CA

Development Of Dormancy And Winter Hardiness In Silver Birch

E. Tapio Palva , Pekka Heino , Markku K. Aalto

  Faculty of Biosciences, Genetics, Viikki Biocenter, University of Helsinki, P.O.Box 56, FIN-00014, Helsinki, Finland

Control of the annual growth cycle of trees requires proper timing of growth cessation, bud set and development of dormancy and winter hardiness in the fall and bud burst in the spring. This seasonal cycle in boreal forests is governed by the special combination of light and temperature. Perception of such cues triggers both physiological and developmental adaptations that ensure optimal growth and survival of boreal and temperate-zone tree species, such as silver birch (Betula pendula). Photoperiodic control appears central to growth cessation and dormancy development in birch manifested in a steep latitudinal cline. It also potentiates the development of full winter hardiness in birch. Our aim is to elucidate the regulatory network for such seasonal control in birch. We have generated a collection of 75 000 ESTs representing about 19 000 birch genes. Statistical comparison of the libraries used in generation of the ESTs and expression profiling with oligonucleotide arrays in distinct photoperiod ecotypes of birch has identified a number of genes differentially expressed in response to short day photoperiod and/or low temperature and suggested candidate genes controlling dormancy and winter hardiness in birch.