Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Plants use circadian rhythms to prepare for battle with insects

Rice University study: Plants make predawn preparations to fend off hungry caterpillars

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.

"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.

VIDEO is available at:

A copy of the PNAS paper is available at:

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is known for its "unconventional wisdom." With 3,708 undergraduates and 2,374 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 4 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to

Jade Boyd | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Ice shelf vibrations cause unusual waves in Antarctic atmosphere

25.10.2016 | Earth Sciences

Fluorescent holography: Upending the world of biological imaging

25.10.2016 | Power and Electrical Engineering

Etching Microstructures with Lasers

25.10.2016 | Process Engineering

More VideoLinks >>>