Plants use internal clock for defense

HOUSTON, Feb. 14 (UPI) -- Plants make use of circadian rhythms to make predawn preparations to fend off hungry insects, researchers at Rice University said.

"When you walk past plants, they don't look like they're doing anything," researcher Janet Braam said in a release Monday. "It's intriguing to see all of this activity down at the genetic level. It's like watching a besieged fortress go on full alert."

Scientists have begun to apply powerful genetic tools to the study of plant circadian rhythms, and found circadian-regulated genes were connected to chemical responses in the plants.

One common plant species, Arabidopsis thaliana, was found to use its circadian clock to increase production of a hormone knows as jasmonote during the day.

Jasmonate regulates the production of metabolites that interfere with insect digestion, researchers said.

"Jasmonate defenses are employed by virtually all plants, including tomatoes, rice and corn," researcher Wassim Chehab said. "Understanding how plants regulate these hormones could be important for understanding why some pests are more damaging than others, and it could help suggest new strategies for insect resistance."