Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Key component indentified that helps plants go green

30.06.2010
A team of researchers from Duke University and the Salk Institute for Biological Studies has found a central part in the machinery that turns plants green when they sense light.

In the Rube Goldberg world of cellular mechanics, this key player turns out to be a garbage truck.

Light is so essential for plants that they have two different systems to take advantage of it, explains Meng Chen, an assistant professor of biology at Duke.

There's the familiar system of organelles called chloroplasts that turn sunlight into fuel via photosynthesis. The photosynthetic pigment inside chloroplasts, chlorophyll, is where the green color comes from.

And then there's a system of light-sensitive proteins called photoreceptors that use light as information and direct plant development and growth. One of the things the plant does with that information is control how it makes chloroplasts. "The greening process is completely dependent on the presence of light. However, how light triggers the making of chloroplasts is still unknown," Chen said.

In a paper appearing in the June 25 issue of Cell, Chen and his team have identified a key intermediary between the light system for information and the light system that makes fuel. The hope is that this knowledge will help researchers use a plant's own photo-sensory systems to increase agricultural yields or improve the photosynthesis of biofuel crops.

"Light is probably the most important environmental cue for a plant," said co-author Joanne Chory, a Howard Hughes Medical Institute investigator at the Salk Institute for Biological Studies. "Understanding how light signaling triggers morphological changes in the plant will have a really big impact on every facet of plant biology."

Plants have an array of photoreceptors that are tuned to different wavelengths of light. One type, called phytochromes, are sensitive to red and far-red light and play a major role in the making of chloroplasts and the growth of the stem, said Chen, who is the first author on the study.

One of the first things that happens when the plant detects light is that these phytochromes move from the cell's cytoplasm to its nucleus, where the genes are kept. The photoreceptors gather in discrete spots known as phytochrome nuclear bodies. In an earlier study, Chen had found that the size and number of phytochrome nuclear bodies was directly related to light intensity.

Chen, who started this line of work as a postdoctoral researcher in Chory's lab at the Salk Institute, ran genetic screens for mutants with abnormal phytochrome nuclear bodies. He identified a new gene, hemera, that seems to be required for both the localization and the signaling of phytochrome.

He named the gene for the Greek goddess of daylight, Hemera. It is present in all land plants studied so far.

Mutant plants without hemera were found to have dramatically reduced sensitivity to red and far-red light, they failed to develop chloroplasts, were albino, and died while still only seedlings. Without Hemera, "a plant is blind to light and the chloroplasts can't develop," Chen said.

The prevailing model of chloroplast development involves signaling molecules called PIFs that hold chloroplast development back when the plant senses darkness. But when phytochromes are activated by light, they destroy the PIFs, clearing the way for chloroplast development. PIFs tended to aggregate around these phytochrome nuclear bodies before being destroyed. Hemera also tended to be found near the nuclear bodies, suggesting that the nuclear bodies were the site of PIF destruction.

In a series of experiments with hemera mutants, the team found these plants tended to have smaller phytochrome nuclear bodies and were unable to remove PIFs in light, which could explain why the mutants weren't making chloroplasts.

The team also found that hemera is structurally similar to a yeast protein called RAD23, that is known to be the garbage truck that rounds up other proteins flagged for destruction and carries them to the place where they are ground up. They inserted Hemera from Arabidopsis plants into yeast that lacked RAD23, and found that it partially took over RAD23's job, Chen said.

Other researchers who contributed to the study include postdoctoral fellows Rafaelo M. Galvão and Meina Li from the Chen laboratory at Duke, and Brian Burger, Jane Bugea and Jack Bolado at the Salk Institute.

Chen's work on this project was supported in part by a National Science Foundation grant from the American Recovery and Reinvestment Act (ARRA) and Duke University. The work at the Salk Institute was supported in part by the National Institutes of Health and the Howard Hughes Medical Institute.

"Arabidopsis HEMERA/pTAC12 Initiates Photomorphogenesis by Phytochromes," Meng Chen, Rafaelo M. Galvao, Meina Li, Brian Burger, Jane Bugea, Jack Bolado, Joanne Chory; Cell, Volume 141, Issue 7, 1230-1240, 25 June 2010 http://www.cell.com/abstract/S0092-8674%2810%2900543-X

Video - http://www.youtube.com/watch?v=yUlGAUtTywk

Karl Leif Bates | EurekAlert!
Further information:
http://www.duke.edu

Further reports about: Arabidopsis thaliana Medical Wellness Pif RAD23 cell death

More articles from Life Sciences:

nachricht Sleep as energy saving mode
21.11.2017 | Universitätsspital Bern

nachricht Water world
20.11.2017 | Washington University in St. Louis

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>