Biologists identify genes controlling rhythmic plant growth

Mustard-plant seedlings glow as the genes that control rhythmic plant growth turn on just before dawn. Click here for more information.

A team of biologists from UC San Diego, the Salk Institute for Biological Studies and Oregon State University has identified the genes that enable plants to undergo bursts of rhythmic growth at night and allow them to compete when their leaves are shaded by other plants.

The researchers report in this week's issue of the journal PLoS Biology that these genes control the complex interplay of plant growth hormones, plant light sensors and circadian rhythms that permit plants to undergo rhythmic growth spurts at specific times of the day or year in response to varying levels of light and other environmental conditions.

Their discovery of the genetic underpinnings of the rhythmic plant movements that enthralled Charles Darwin more than a century ago could eventually allow scientists to design crops that can grow substantially faster and produce more food than the most productive varieties today.

"This paper builds on our previous findings that almost all plant genes are expressed only at a particular time of the day," said Howard Hughes Medical Institute investigator Joanne Chory, a professor in the Salk Institute's Plant Biology Laboratory.

"What we found is a whole raft of genes that could be the actual molecular switches that define plant growth at the molecular level," said Steve Kay, Dean of the Division of Biological Sciences at UC San Diego and one of the leaders of the research team. "The more we understand about these genetic mechanisms and how they switch on and off plant growth, the better we will be at designing tailor-made crops to increase our production of food and fuel for the world's rapidly growing population."

"It was known that the circadian clock confers an adaptive advantage to plants in nature, and these findings provide a direct mechanism by which plants optimize their growth by synchronizing hormone signaling with the environment," said first-author Todd Michael, a former postdoctoral fellow at Salk who is now an assistant professor of genomics and bioinformatics at the Waksman Institute and Rutgers University. Other coauthors included UCSD postdoctoral fellows Ghislain Breton and Samuel Hazen, and assistant professor of genome biology, Todd Mockler, and graduate student Henry Priest of Oregon State.