Breeding tougher crops that can resist climate change

Plants are exposed to huge variations in temperature through the seasons as well as big differences between night and day. To cope with this, they sense the temperature around them, and adjust their growth accordingly.

Now, remarkably, scientists have discovered that plants have a built-in thermometer that they use to control their development and this could mean we may be able to breed crops that are resistant to climate change.

Publishing in the journal Cell, the biologists have identified a thermometer gene that could be crucial for breeding crops able to cope with the effects of serious changes in the weather.

Plants can sense differences of one degree Celsius. Climate change has already had significant effects, bringing forward when some plants flower, and changing global distributions of species. Although the effect of temperature on plants has been known for hundreds of years, it has been a mystery until now how temperature is sensed.

To solve this problem, Dr Vinod Kumar and Dr Phil Wigge - at the John Innes Centre in Norwich, eastern England - looked at all of the genes in the model plant Arabidopsis to see which ones are switched on by warmer temperature. They connected one of these genes to a luminescent gene to create plants that give off light when the temperature is increased.

In this way, the team could screen for mutants that could no longer sense the proper temperature. One mutant was particularly interesting, because it lost the ability to sense temperature correctly.
The plant behaved as if its surroundings were hot all the time - the scientists could see this because the plant was luminescent when the area around it was warm or cold.

"It was amazing to see the plants," said Dr Kumar who discovered the mutant plant. "They grew like plants at high temperature even when we turned the temperature right down."

This plant has a single defect that affects how a special version of a histone protein works. These proteins bind to DNA (deoxyribonucleic acid) matter and wrap it around them, and therefore control which genes are switched on.

Remarkably, when this specialized histone is no longer incorporated into DNA, plants express all their genes as if they are at a high temperature, even when it is cold. This told the scientists that this specialized histone is a key regulator of temperature responses.

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