Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers block plant hormone

21.08.2014

A small molecule inhibits jasmonic acid and helps to explain its effects

Researchers trying to get new information about the metabolism of plants can switch off individual genes and study the resulting changes. However, Erich Kombrink from the Max Planck Institute for Plant Breeding Research in Cologne and Markus Kaiser from the University of Duisburg-Essen adopt a different approach.


Jarin1 inhibits the enzyme JAR1 by displacing the natural substrate, Jasmonoyl-isoleucine (JA-Ile), from its binding site. Both substances overlap, so that JAR1 can no longer fulfil its tasks. The left panel shows an overview of the entire enzyme; the right panel a view into the active centre.

© Corey S. Westfall, Washington University, St. Louis

They identify small molecules that block specific components of the metabolic process like brake pads and prevent the downstream reactions. In their search for these molecules, they use a biological selection process involving intact plants. This strategy has long been exploited in drug research. Its application in the plant sciences, however, is relatively new.

Kombrink, Kaiser and their colleagues have identified a molecule that interferes with the effect of jasmonic acid. This plant hormone influences flower formation, root growth, defence against herbivores and infections, wound healing, ageing of plants, and much more.

... more about:
»Arabidopsis »acid »chains »compounds »genes »jasmonic »signalling

Although many questions about plant metabolism can be answered through targeted gene mutations, the method has its limits. This is also demonstrated in the case of jasmonic acid and its derivatives. So far, only one signalling chain has been discovered, but this cannot explain the wide-ranging effect of this plant hormone. Therefore, other hitherto undiscovered signalling paths and action mechanisms must exist.

To find out more about them, Kombrink and Kaiser have adopted an approach that is similar to one used in medicine. Their strategy is based on the blocking of important metabolic pathways using low molecular weight compounds, which are easily assimilated by the plant. While in medical therapy such compounds are assimilated through the blood, in the plant they are introduced through the root.

The scientists embarked on their search with a screening of Arabidopsis thaliana and treating the plants with compounds in such a way that the desired selection could be identified by a conspicuous trait. Of the 1728 substances from a commercial compound library tested 16 emerged as inhibitors.

This number was further reduced using more selective tests. In the end, only one substance turned out to be a specific inhibitor of the jasmonic acid signalling pathway and was given the name Jarin-1. “In terms of its basic structure, the substance is a plant alkaloid, whose two amino groups can carry different side chains,” Kombrink explains. “However, its effect is associated with a particular side chain in one of the positions. Other side chains impair the activity of the substance. We also deliberately synthesised it once again to be certain that we had understood its chemical structure correctly.”

The scientists also looked for the target of the newly discovered inhibitor. The known signalling chain starts with the conjugation of the jasmonic acid with the amino acid isoleucine by an enzyme called JAR1. The resulting pair leads to the expression – following various detours – of the genes necessary for the relevant effect of the jasmonic acid. Kombrink and Kaiser were able to show that JAR1 is the target of the newly discovered inhibitor. Due to the inhibition, the jasmonic acid conjugated with isoleucine does no longer accumulate in the cell. As a result genes are not expressed because the jasmonic acid–isoleucine pair no longer activates the genes’ starting point.

The Jarin-1 inhibitor identified by Kombrink and Kaiser not only works in Arabidopsis but also in Cardamine hirsuta or hairy bittercress. “So we are obviously dealing with a broadly applicable molecule,” comments Kombrink. Under the effect of the inhibitor, the plants show the same features as they do following the targeted mutation of genes from the jasmonic acid signalling pathway.

The scientists also investigated the exact location where the molecule takes effect. They succeeded in demonstrating that it binds to the active centre of JAR1 and inhibits the natural substrate. “Our molecule is not a classical competitive inhibitor,” says Kombrink. “But its effect can be explained, at least in parts, by displacement of the substrate from its binding site.”

Small molecules are interesting new tools for plant research. Through their work, the researchers show how it is possible to search for them systematically and to identify their molecular mode of action.

Contact 

Dr. Erich Kombrink

Max Planck Institute for Plant Breeding Research, Köln

Phone: +49 221 5062-320

 

Prof. Dr. Markus Kaiser

Universität Duisburg-Essen

Phone: +49 201 183-4980

 

Original publication

 
Christian Meesters et al.
A chemical inhibitor of jasmonate signaling targets JAR1 in Arabidopsis thaliana
Nature Chemical Biology, 17 August 2014, doi: 10.1038/nchembio.1591

Dr. Erich Kombrink | Max-Planck-Institute
Further information:
http://www.mpg.de/8367047/inhibitor-jasmonate

Further reports about: Arabidopsis acid chains compounds genes jasmonic signalling

More articles from Life Sciences:

nachricht A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich

nachricht New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>