'Biological clock' genes control pl...( CORVALLIS Ore. More than 125 years ...)

CORVALLIS, Ore. More than 125 years ago Charles Darwin first reported that most plants grow in a spurt during the night, not the day and this week, scientists are reporting the discovery of the genes that control this phenomenon.

These rhythmic growth spurts, and the ability of plants to move in response to light, are actually controlled by genes involved in circadian rhythms the "biological clock" genes that are influenced by light and dark, vary their activity based on time of day, and are increasingly found in both plants and animals to control a wide variety of functions, ranging from growth to nervous system function and even fertility.

"This is an incremental but important step in understanding how plants grow," said Todd Mockler, an assistant professor of botany at Oregon State University, and co-author of the report with colleagues at the University of California/San Diego and the Salk Institute for Biological Studies.

Ultimately, more understanding of these growth genetics could allow scientists to create plants that grow faster, produce more food or have other useful characteristics, the researchers said.

The findings will be reported this week in PloS Biology, a professional journal. The research was funded by the National Science Foundation, National Institutes of Health and the Howard Hughes Medical Institute.

"We now know that the expression of certain genes and hormones at night and just before dawn is important for plant growth," Mockler said. "During the day, the plant focuses on other tasks, such as the photosynthesis that produces its energy. And plants are not only responding to time of day, but also the length of daylight to control such things as flowering time and stem length."

When such mechanisms are more fully analyzed, it may be possible to influence them with genetic modification, Mockler said.

This advance was made possible largely by the use of DNA microarrays
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