Molecular Regulation of Latitudinal Climate Adaptation in Trees

For trees growing at higher latitudes, it is important to adapt their life cycle and growth to the varying day lengths and temperatures that occur over the year.

This requires a precise timing of when to stop growth in fall and form protective winter buds, and when to flush those buds and start growing in spring.The trigger to stop growing in the fall is the sensing of the shorter daylengths, while It is the rising temperatures during spring that are important for the timing of bud flush.

Work in my lab has shown that all these processes are controlled by FT-like genes.

In aspen trees the FT genes have triplicated and two of the genes, called PtFT2a and PtFT2b, are expressed in the summer and are responsible for the maintenance of vegetative growth, while the third gene, PtFT1, is responsible for the release of winter dormancy and bud flush in the spring.

The timing of bud set displayed by aspen trees growing at different latitudes is associated to almost 70% by genetic variation in the FT2 locus.

In this project we aim to understand the mechanistic basis behind this variation by studying the regulation of the PtFT genes, both in terms of cis-regulatory elements and the function of putative upstream regulators.

This work will be central for our understanding of how photoperiodic regulation and latitudinal adaptation in trees is controlled, how a changing climate will affect this process and how this knowledge can provide targets for breeding of better adapted trees.