© 1997 Heron Publishing—Victoria, Canada
Changes in ABA and gene expression in cold-acclimated sugar maple
Annick Bertrand (1), Gilles Robitaille (1), Yves Castonguay (2), Paul Nadeau (2) and Robert Boutin (1)
1. Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, P.O. Box 3800, Sainte-Foy, Québec G1V 4C7,
Canada / 2. Agriculture and Agri-Food Canada Research Station, 2560 Boul Hochelaga, Sainte-Foy, Québec G1V 2J3, Canada / Received April 25, 1996
Summary
To determine if cold acclimation of sugar maple (Acer saccharum Marsh.) is associated with specific changes in gene expression under natural hardening conditions, we compared bud and root
translatable mRNAs of potted maple seedlings after cold acclimation under natural conditions and following spring dehardening.
Cold-hardened roots and buds were sampled in January when tissues reached their maximum hardiness. Freezing tolerance, expressed
as the lethal temperature for 50% of the tissues (LT50), was estimated at –17 °C for roots, and at lower than –36 °C for buds. Approximately ten transcripts were specifically synthesized
in cold-acclimated buds, or were more abundant in cold-acclimated buds than in unhardened buds. Cold hardening was also associated
with changes in translation. At least five translation products were more abundant in cold-acclimated buds and roots compared
with unhardened tissues. Abscisic acid (ABA) concentration increased approximately tenfold in the xylem sap following winter
acclimation, and the maximum concentration was reached just before maximal acclimation. We discuss the potential involvement
of ABA in the observed modification of gene expression during cold hardening.
Keywords:
Acer saccharum, cold hardening, freezing tolerance, in vitro translation.
