Tree survival in Nordic winters

ipm

How do trees synchronize growth and development with the seasons? And what mechanisms do they rely on to survive the harshness of the Nordic winters?

Plant Cell Cover January 2011

Recent investigations in the group of Chris van der Schoot at IPM led to a breakthrough in our understanding by showing that trees regulate production of intercellular signals and signaling conduits to anticipate seasonal progression. This will help to prognose how forest trees will perform during climate change.

The Plant Cell
The researchers published their work in the world’s most prestigious plant science journal ‘The Plant Cell’ . It is a follow up of a previous Plant Cell publication of the same group . The research for both publications was financed by the FRIBIO program of the Norwegian Research Council and carried out in collaboration with scientists from the Centre of Excellence in Plant Signaling at Helsinki University.

Shoot apical meristem of growing poplar and targeting of transgenically expressed enzymes (green) to plasmodesmata (red). Copyright © 2011 The Plant Cell Online by the American Society of Plant Biologists.

Cartoon summarizing the major events during dormancy cycling.
Copyright © 2011 The Plant Cell Online by the American Society of Plant Biologists

Populus
The group studies the model tree Populus, which has the advantage that its genome is sequenced. In late summer shortening days trigger various molecular, structural and physiological changes in the shoot tip of Populus, culminating in the formation of winter buds that can endure very low temperatures.

Crucial genes
The present work identifies crucial genes which encode signaling peptides and cell wall proteins that are expressed at specific phases of the activity-dormancy cycle, and in synchrony with seasonal progression. The investigators identified 10 Populus genes that encode structurally distinct cell wall 1,3-β-glucanases. Their sites of action were found to be plasmodesmata, tiny communication and transport channels that link-up all cells of the entire plant system into an elaborate symplasmic network. They showed that these 1,3-β-glucanases are differently regulated by daylength, temperature, and the gibberellins (hormones) GA3 and GA4, to collectively regulate the long- and short-distance signaling paths in plants in synchrony with the seasons.

Conduit-regulators
In addition, these events are closely coordinated with the transcription of genes that encode informational (signaling) peptides, like flowering time genes, underscoring the vital role of the conduit-regulators in the signaling processes that regulate the seasonal life of plants. As pointed out by Päivi Rinne, lead author on the current publication, we now have a mechanistic framework in place that explains the seasonal events in perennials as driven by two intercoordinated forces, signal production and signal conduit regulation. The science editor of Plant Cell G. Bertoli aptly highlighted the discoveries under the title ‘Dormancy cycling: the symplasmic connection’.

Lead author Päivi Rinne

In the near future, the specific 1,3-β glucanases that regulate conduit functionality will prove to be important targets for manipulation, aimed at modifying tree behaviour under a changing climate.

Since plasmodesmata, used by the plant itself for transport and signaling purposes, are also targets of manipulation in an arms race between plants and viruses as well as other pathogens, the present work will open up new avenues for the understanding and control of plant-pathogen interactions.

Publisert: 14.04.11
Oppdatert: 15.04.11
Utskriftsvennlig versjon

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