Unravelling the genetic network mediating temperature control of dormancy release and bud break in hybrid aspen

In order to survive extreme low temperature, trees in boreal and temperate regions cease growth, enclose the leaf primordia and shoot apical meristem within a protective bud structure and establish dormancy prior to the advent of winter.

Dormancy prevents premature activation of growth until the advent of spring when the leaf primordia restart growth (bud break) after dormancy is released. Dormancy is released gradually by prolonged exposure to low temperature. After dormancy is released, transition to bud break occurs in early spring as temperature rises.

Precise temporal regulation of dormancy release and bud break is critical for productivity as premature bud break can lead to fatality from sudden frosts in early spring whereas delayed bud break leads to loss of productivity from curtailed growing season.

The aim of this application is to identify the genetic framework for temperature mediated control of dormancy release and bud break that is poorly understood using cell biological, genetical and physiological approaches in model tree hybrid aspen.

In particular, we aim to uncover the role of antagonistically acting transcription factors SVL and AGL8 and how they interact with hormonal pathways in regulating cell-cell communication via intercellular channels called plasmodesmata to mediate temperature control of dormancy release and bud break.