Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

In Fight Against Pathogens, Calcium Helps Plants Make Their Own Aspirin

05.01.2009
Calcium builds strong bones, good teeth—and healthy plants, according to a new study from Washington State University.

Experiments show that calcium, when bound to a protein called calmodulin, prompts plants to make salicylic acid (SA) when threatened by infection or other danger. SA is a close chemical relative of aspirin. In plants, SA acts as a signal molecule that kicks off a series of reactions that help defend against external threats.

That plants make salicylic acid has been known for more than 100 years, said B.W. Poovaiah, Regents Professor and director of the study, but the role of calcium in signaling a plant to make SA has not been known before.

“We are now beginning to understand the molecular mechanism connecting the calcium/calmodulin signaling to plant immunity,” said Poovaiah.

The study will appear in an upcoming issue of the journal Nature and is now available online at http://dx.doi.org/10.1038/nature07612.

Poovaiah said that in controlling salicylic acid level, calcium acts like a gatekeeper within the cells of a plant, directing incoming information and helping the plant respond to such dangers as pathogen attacks. Normal, healthy plants have a low level of SA in their cells. That level rises when the plant is threatened by infection or environmental stress.

“When we expect danger, we try to take precautions,” said Poovaiah. “Plants cannot run away. Plants have to turn on their built-in system to protect themselves. The plant has to produce different signal molecules. One of them is salicylic acid.”

According to lead author, assistant research professor Liqun Du, SA sets off defensive measures within the plant, such as the “hypersensitive reaction” in which cells around an infection site die, forming a barrier that keeps the pathogen from invading deeper into the plant. That provides protection against the immediate threat. SA also activates the plant’s systemic acquired resistance, a form of immunity that protects the plant from further pathogen attacks.

But a rise in SA levels also causes the plant to slow its growth, perhaps saving its strength for the battle against the pathogen. That sets up a challenging situation for both the plant—grow faster or protect myself better?—and farmers, who might view SA as a tool to protect their plants from disease. A plant that makes high levels of SA all the time will be safe from infection but will grow slowly. A plant that makes little or no SA will grow like gangbusters but be very susceptible to infection.

“It’s a fine balance,” said Du. “Too much is bad; too little is bad.”

Working with the small mustard plant Arabidopsis thaliana, Poovaiah’s research team showed that the key step in this balancing act is the interaction between calcium/calmodulin and a protein called AtSR1, which suppresses the production of salicylic acid. Stress or infection causes a spike in calcium within the plant cells, which, in combination with calmodulin, acts as a specific signal controlling the activity of AtSR1 and the formation of SA.

In an environment with few pathogens, a plant will have low levels of SA. The plant lets its guard down and devotes more resources to growth. If it becomes infected, SA production goes up, and the plant dials back its growth and puts more resources into defense.

The importance of AtSR1 was especially clear in experiments in which plants were engineered to have more or less AtSR1 than normal. Plants that have extra AtSR1 make almost no SA. They grow larger and faster than a normal plant, but easily succumb to infection. Plants that lack the gene for AtSR1 develop high levels of SA and deploy their immune responses all the time. They are nearly impervious to infection, but small in size. The same is true of plants whose AtSR1 has been changed so it cannot bind to calcium/calmodulin, demonstrating the crucial role played in this system by calcium and calmodulin.

The paper is titled “Calcium/Calmodulin Regulates Salicylic Acid-mediated Immune Response in Plants through AtSR1/CAMTA3.”

Joe Poovaiah | Newswise Science News
Further information:
http://www.wsu.edu

Further reports about: Aspirin AtSR1 Calcium Pathogen Plants pathogens plant cell salicylic signal molecule

More articles from Life Sciences:

nachricht Molecular libraries for organic light-emitting diodes
24.04.2017 | Goethe-Universität Frankfurt am Main

nachricht Fine organic particles in the atmosphere are more often solid glass beads than liquid oil droplets
21.04.2017 | Max-Planck-Institut für Chemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Molecular libraries for organic light-emitting diodes

24.04.2017 | Life Sciences

Research sheds new light on forces that threaten sensitive coastlines

24.04.2017 | Earth Sciences

Making lightweight construction suitable for series production

24.04.2017 | Machine Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>