Wilczek

PROVIDENCE — A team led by Brown University researchers says it has unraveled some of the complex genetic signals that integrate temperature and sunlight measurements to tell a plant the best time to flower.

The research, published today by the journal Science, could guide future breeding programs of important crops to help expand their range, and could help predict how plants will react to a changing climate.

“People have looked at all these environmental signals separately, but we really wanted to know how plants integrate the response from these combined signals to come up with a good decision of when to flower,” said Amity M. Wilczek, postdoctoral research associate in ecology and evolutionary biology at Brown and chief author of the study.

The work was done on the weed species Arabidopsis thaliana, sometimes called mouse-ear cress, which is related to canola, cabbage and broccoli.

But how a plant actually behaves in the wild depends on how those genes interact. The genes looking at different environmental signals may be releasing chemicals that give conflicting messages. Other genes weigh that input, then send out chemical signals of their own to control flowering.

The researchers have come up with a way to assess that balancing act in a lab piled high with boxes containing the dried remains of 55,000 of the plants, each individually wrapped and labeled, grown at five sites in Finland, Germany, Spain and the United Kingdom from 2006 to this past fall.

Workers examine each plant, measuring it, and going through the tedious process of counting the thousands of tiny fruits and pin-hole-size seeds on each, using them as a gauge of how well it grew in that climate and how likely it was to produce offspring.

Because the plants have varying genetic makeups — some lack a gene that responds to how long the sun is up, for example — the researchers can develop a computer model simulating how the various genes interact, leading to success or failure in a particular climate.

Wilczek said that is equivalent to being able to predict how rapidly any car will be able to accelerate from 0 to 60 mph based on knowledge of its internal characteristics such as engine size and type of carburetor, and environmental factors such as the type of fuel and roughness of the test track.

This plant was studied, she said, not because it has any value, but because its genetic blueprint has already been mapped, making it easier to see how it operates so, hopefully, the knowledge can be applied elsewhere.

“The bad news is, it’s a weed,” she said. “The hopeful news is that because other plants have a similar genetic architecture, which is the same way these pathways integrate environmental information, we have high hopes we can transfer this over to other crop species,” such as wheat and barley.

And even when a plant has different genes that control the action, said Wilczek, “the pathways work in a similar way.”

gemery@projo.com