How Plants Cope With The Cold Light Of Day, And Why It Matters For Future Crops

On bright chilly mornings you can either snuggle down under the duvet or leap up and seize the day.

However, for photosynthesizing plants, this kind of dawn spells danger, so they have evolved their own way of making cold mornings tolerable.

Research led by the John Innes Centre has discovered a cold "coping" mechanism that is under the control of the plant biological clock and could offer solutions to breeding more resilience into crops less suited to cold climates.

"We've identified a new process that helps plants tolerate cold. It's controlled by the biological clock of plants, and we think it could be especially important on cold, bright mornings," says Professor Antony Dodd, a group leader at the John Innes Centre.

"Crops such as winter wheat and winter oilseed rape experience cold temperatures for periods of their cultivation," he continues. "We think that the mechanism that we have discovered could provide greater resilience of photosynthesis to cold temperatures. It represents an interesting target for future precision breeding of climate resilient crops."

Cold temperatures can damage plant cells, particularly when combined with too much light or during freezing temperatures. Hence why those bright cold mornings are so dangerous to plants.

The researchers wanted to know how information about low temperatures is communicated to the chloroplasts, the site of photosynthesis inside a plant cell, essential for all our major crops.

Chloroplasts contain their own small genome that reflects their evolutionary past as photosynthetic bacteria, before they were engulfed and co-opted by plants to carry out photosynthesis. Throughout evolution many genes from the chloroplast transferred to the plant nuclear genome, but chloroplasts have held on to some essential genes.

In this research the team focussed on one such bacterial genetic legacy called a sigma factor (SIG5). In bacteria, comparable sigma factors contribute to responses to temperature.