Vinod Kumar and Phil Wigge have identified a histone variant which acts as a thermometer switching genes on or off depending on the temperature. Their work could be crucial for breeding crops able to cope with the effects of climate change. 

The duo studied genes in the model plant Arabidopsis to see which are switched on by warmer temperatures. They screened plants engineered to give off light at high temperatures for mutant genes unable to sense the proper temperature. One mutant¬ in particular – a histone variant – lost the ability to sense temperature correctly and behaved as though it was hot all the time.

 “It was amazing to see the plants,” Dr Kumar said, “They grew like plants at high temperature even when we turned the temperature right down.”

Histone proteins bind to and wraps around DNA controlling which genes are switched on. When this histone is no longer present, the plant express all their genes as if they are at a high temperature, leading Kumar and Wigge to conclude that this specialised histone is a key regulator of temperature responses.

At lower temperatures, the histone variant binds tightly to the plants DNA, blocking the gene from being switched on, but as temperature increases, the histone starts to drop off the DNA and the gene is switched on.

The histone variant was found to control a gene that has enabled some plant species to adapt to climate change by rapidly accelerating their flowering.  Other species that have not adapted are going locally extinct at a high rate. How plants adapt to their environment and use temperature sensing will enable scientists to examine how different species respond to further increases.

“We may be able to use these genes to change how crops sense temperature,” said Dr Wigge, “If we can do that then we may be able to breed crops that are resistant to climate change.”