Reforestation logistics and forest nursery management depend on the physiological status of the trees. The lifting and cold storage of insufficiently hardened trees lead to reduced vitality, frost damage and desiccation. The identification of molecular processes underlying winter hardiness will allow for the development of rapid and reliable tools to determine seedling condition. cDNA microarray technology will be used to analyse gene expression patterns in economically and ecologically important forest tree species in combination with physiological and morphological screening. This multidisciplinary approach will result in a detailed picture of molecular events involved at the onset and release of dormancy and hardiness. Genes with a strong predictive value will be selected for future implementation in molecular hardiness tests that will aid in improving forestation planning and forest tree nursery management.
The objectives of this project are:
1) to identify genes and molecular pathways involved at the onset and release of winter hardiness and dormancy in woody species using cDNA microarrays, and to postulate a conceptual model describing the molecular events underlying these processes
2) to select a set of key genes, of which the expression patterns can be used to describe the various stages of dormancy and hardiness
3) to evaluate the merits of these key genes as a molecular diagnostic tool for nursery practice and improved forestation.
Progress to Date
In the first two seasons, dormancy and hardiness development were monitored in field-grown seedlings and in seedlings cultured in controlled environments. Both types of experiments were performed using pine and beech and resulted in a series of physiologically well-defined samples, spanning the whole period of dormancy and cold hardiness development.
During controlled growth, decreasing temperature was separated from decreasing day-length to allow an independent study of genes involved in these intertwined but discrete processes. In addition, cold and warm shocks were applied to allow identification of genes and pathways involved in the plants' reaction on varying temperatures. It appeared that these temperature shocks hardly influenced the ongoing process of dormancy and frost tolerance development. In addition, the regimes in which day-length and temperature were kept constant did not inhibit the development of dormancy or cold tolerance.
In general, physiological experiments indicate that dormancy development in beech is much more pronounced compared to pine. Thus, a cDNA library from beech buds has been constructed and will be used as a base for a small beech array that can be used to analyse specifically dormancy/hardiness development in beech.
Concurrently, effort has been put into the development of easy-to-use diagnostic tests, as a step towards implementation in practice. The family of dehydrin genes has been used as a model. Dehydrins code for proteins that are present throughout the plant kingdom, and play important roles in dormancy and defence against dehydration and other abiotic stresses.
Scientist responsible for the project
Dr MONIQUE VAN WORDRAGEN
Bornsesteeg 59 Box 17
6700 AA Wageningen
Netherlands (The) - NL
Phone: +31 317 475000
Fax: +31 317 475347
||Agrotechnological Research Institute
||01 March 2001
||2 616 949 €
|Total EC contribution
||1 308 464 €
|Web address of the project