Featured Research

from universities, journals, and other organizations

Plants use circadian rhythms to prepare for battle with insects

Date:
February 13, 2012
Source:
Rice University
Summary:
In a study of the molecular underpinnings of plants' pest resistance, biologists have shown that plants use circadian rhythms to both anticipate raids by hungry insects and to time the production of defensive hormones that protect against insect attack. The researchers demonstrated that when the plants' timing was shifted, the plants were defenseless against daytime-feeding caterpillars.

Rice University biologists found that plants with altered circadian clocks were unable to defend themselves against leaf-eating cabbage looper caterpillars.
Credit: Tommy LaVergne/Rice University

In a study of the molecular underpinnings of plants' pest resistance, Rice University biologists have shown that plants both anticipate daytime raids by hungry insects and make sophisticated preparations to fend them off.

Related Articles


"When you walk past plants, they don't look like they're doing anything," said Janet Braam, an investigator on the new study, which appears this week in the Proceedings of the National Academy of Sciences. "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."

Braam, professor and chair of Rice's Department of Biochemistry and Cell Biology, said scientists have long known that plants have an internal clock that allows them to measure time regardless of light conditions. For example, some plants that track the sun with their leaves during the day are known to "reset" their leaves at night and move them back toward the east in anticipation of sunrise.

In recent years, scientists have begun to apply powerful genetic tools to the study of plant circadian rhythms. Researchers have found that as many as one-third of the genes in Arabidopsis thaliana -- a widely studied species in plant biology -- are activated by the circadian cycle. Rice biochemist Michael Covington found that some of these circadian-regulated genes were also connected to wounding responses.

"We wondered whether some of these circadian-regulated genes might allow plants to anticipate attacks from insects, in much the same way that they anticipate the sunrise," said Covington, now at the University of California, Davis.

Danielle Goodspeed, a graduate student in biochemistry and cell biology, designed a clever experiment to answer the question. She used 12-hour light cycles to entrain the circadian clocks of both Arabidopsis plants and cabbage loopers, a type of caterpillar that eats Arabidopsis. Half of the plants were placed with caterpillars on a regular day-night cycle, and the other half were placed with "out-of-phase" caterpillars whose internal clocks were set to daytime mode during the hours that the plants were in nighttime mode.

"We found that the plants whose clocks were in phase with the insects were relatively resistant, whereas the plants whose clocks were out of phase were decimated by the insects feeding on them," Goodspeed said.

Wassim Chehab, a Rice faculty fellow in biochemistry and cell biology, helped Goodspeed design a follow-up experiment to understand how plants used their internal clocks to resist insect attacks. Chehab and Goodspeed examined the accumulation of the hormone jasmonate, which plants use to regulate the production of metabolites that interfere with insect digestion.

They found that Arabidopsis uses its circadian clock to increase jasmonate production during the day, when insects like cabbage loopers feed the most. They also found that the plants used their internal clocks to regulate the production of other chemical defenses, including those that protect against bacterial infections.

"Jasmonate defenses are employed by virtually all plants, including tomatoes, rice and corn," 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."

The research was supported by the National Science Foundation and Rice University. Additional co-authors include Rice undergraduate Amelia Min-Venditti.


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Danielle Goodspeed, E. Wassim Chehab, Amelia Min-Venditti, Janet Braam, And Michael F. Covington. Arabidopsis synchronizes jasmonate-mediated defense with insect circadian behavior. Proceedings of the National Academy of Sciences, 2012 DOI: 10.1073/pnas.1116368109

Cite This Page:

Rice University. "Plants use circadian rhythms to prepare for battle with insects." ScienceDaily. ScienceDaily, 13 February 2012. <www.sciencedaily.com/releases/2012/02/120213185654.htm>.
Rice University. (2012, February 13). Plants use circadian rhythms to prepare for battle with insects. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2012/02/120213185654.htm
Rice University. "Plants use circadian rhythms to prepare for battle with insects." ScienceDaily. www.sciencedaily.com/releases/2012/02/120213185654.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Dinosaur Species Found in Museum Collection

New Dinosaur Species Found in Museum Collection

Reuters - Innovations Video Online (Nov. 27, 2014) A British palaeontologist has discovered a new species of dinosaur while studying fossils in a Canadian museum. Pentaceratops aquilonius was related to Triceratops and lived at the end of the Cretaceous Period, around 75 million years ago. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
Powered by NewsLook.com
Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins