Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How Plants Measure Temperature

16.11.2016

Research team shows how plants use a light receptor as a thermosensor

Plants respond very sensitive to temperature changes in their environment. At 22 degrees Celsius, for example, the model plant Arabidopsis shows compact growth. But if the temperature rises only a few degrees, plants exhibit an increased elongation growth in the shoot and leaves, enabling plant organs to cool down more easily by evaporation.


The level of active phytochrome B is regulated by light and temperature. Phytochrome B is inactivated more strongly at higher temperatures, promoting elongation growth of plants. Photo: Cornelia Klose

How plants sense temperature was unknown, until now. In two complementary studies published in Science magazine, researchers from the University of Freiburg collaborated with researchers from Cambridge, England; Buenos Aires, Argentina; and St. Louis, Missouri, USA, to demonstrate how the light receptor phytochrome B also works as a temperature sensor in plants.

Phytochromes are photoreceptor proteins that control a number of physiological processes in higher plants, including seed germination, seedling development, induction of flowering and the shade avoidance. The spectral composition of a plant’s light environment changes according to where the plant is growing: The proportion of red light is high in the direct sunlight, while in the shade of vegetation, blue and red light is filtered out, and far red becomes enriched.

Phytochromes can absorb light and act as light driven molecular switches. While the red light portion in sunlight activates phytochromes, far red light inactivates them. Based on this, plants are able to determine the amount of red light in their light environment. Active phytochrome B inhibits elongation growth and promotes compact plant growth instead. It binds to regulatory sequences, or promoters, of certain genes involved for example in the regulation of elongation growth, thus controlling their activity.

It has been known for some time that phytochromes can change from the active to the inactive state, regardless of light conditions. This process is known as dark reversion. The plant physiologists from the University of Freiburg demonstrated previously that the inactivation of phytochrome B via dark reversion can occur in reactions with two different speeds.

A slower dark reversion mechanism ensures that the amount of active phytochrome B gradually declines during the night. A second, about 100 times faster reversion process competes with the light activation of phytochrome B and thus allows the plant to measure the intensity of light during the day. Besides, the researchers discovered that the speed of these two inactivation processes depends strongly on temperature.

Using a special spectroscopy method that allows measuring the amount of active phytochrome B in living seedlings, the scientists demonstrated how much temperature affects the two dark reversion rates. The temperature dependency of the slower dark reversion reaction determines how long phytochrome B remains active during the night and can therefore bind to the gene promoters.

At higher temperatures, phytochrome B is inactivated more rapidly and is released from promoters faster than at lower temperatures. Temperature also influences the activity of phytochrome B during the day. At higher temperatures, the researchers detected reduced levels of the photoreceptors’ active form already in the light phase that was caused by the temperature-dependency of the fast dark reversion mechanism.

Rising temperatures inactivate phytochrome B, particularly in weak light, which in turn promotes elongation growth. Using these mechanisms, plants are able to adapt their development to changes in their environment.

The researchers involved in the studies are Dr. Cornelia Klose, Prof. Dr. Andreas Hiltbrunner, and Prof. Dr. Eberhard Schäfer from the Department of Molecular Plant Physiology of the Institute of Biology II at the University of Freiburg. Hitbrunner and Schäfer are members of the BIOSS Centre for Biological Signalling Studies cluster of excellence, also at the University of Freiburg.
Original publications:
Martina Legris, Cornelia Klose, E. Sethe Burgie, Cecilia Costigliolo, Maximiliano Neme, Andreas Hiltbrunner, Philip A. Wigge, Eberhard Schäfer, Richard D. Vierstra, Jorge J. Casal (2016). Phytochrome B integrates light and temperature signals in Arabidopsis. Science. DOI: 10.1126/science.aaf5656

Jae-Hoon Jung, Mirela Domijan, Cornelia Klose, Surojit Biswas, Daphne Ezer, Mingjun Gao, Asif Khan Khattak, Mathew S. Box, Varodom Charoensawan, Sandra Cortijo, Manoj Kumar, Alastair Grant, James C. W. Locke, Eberhard Schäfer, Katja E. Jaeger, Philip A. Wigge (2016). Phytochromes function as thermosensors in Arabidopsis. Science. DOI: 10.1126/science.aaf6005


Contact:
Dr. Cornelia Klose
Faculty of Biology
University of Freiburg
Phone: +49 (0)761 / 203 - 2627
E-Mail: cornelia.klose@biologie.uni-freiburg.de

Weitere Informationen:

https://www.pr.uni-freiburg.de/pm/2016/pm.2016-11-15.160-en?set_language=en

Rudolf-Werner Dreier | Albert-Ludwigs-Universität Freiburg im Breisgau

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

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

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>