Plants' natural circadian rhythm genes revealed

A gene that triggers plants to become dormant at night and controls flowering has been discovered by scientists. Computer models of cress plants genes showed how 12 genes work together to set plants' internal clocks, University of Edinburgh researchers said.

They found that a protein, known as TOC1, previously associated with helping plants to wake up, dampened down gene activity at night. Professor Andrew Millar said "it was a big change in thinking". Plants, animals and even bacteria go through a daily 24-hour routine, known as a circadian rhythm, which allow them to make tiny adjustments as daylight changes, and adapt to changing seasons. Prof Millar said: "Just like humans you should think about plants having rhythms."

"Having a biological clock is particularly important for plants to prepare for daylight and at night-time [to] store energy for growth. We now understand how the dozen or so genes work and are typical to particular times of the day," he said.

Prof Millar said the results would help further research into the flowering of other plants - particularly crops such as wheat, barley and rice. "We now understand how it all fits together and how the same genes control rhythms in all plants as far back as single-celled algae."

Another study run independently in Barcelona has also made similar findings to the Edinburgh research. Professor Paloma Mas, of the Centre for Research in Agricultural Genomics in Spain, said: "We can now extend the knowledge we have gained of cyclic processes to the major crops and other plants of agronomic interest." 

Prof Millar said the new data would help scientists discover more about other plant genes. "We now know about 12 genes - but we would still like to know about the ones that control photosynthesis, nitrogen use, and petal opening and fragrance."