Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Feeding caterpillars make leaves shine

05.06.2015

Scientists visualize calcium signals in plants which are elicited by wounding and ultimately regulate defense responses against herbivores.

When a plant is attacked by herbivores, this triggers a number of physiological responses in the plant. Calcium ions are important messengers for the processing of wound signals in plant cells. They regulate signal transduction and indirectly control plant defense mechanisms.


The image shows the amounts of light accumulated over a period of 30 minutes, highlighting the changing calcium concentrations. These are represented by a color code (blue=low, red=high).

Victoria Kiep / Martin Luther University, Halle-Wittenberg; Jyothilakshmi Vadassery / Max Planck Institute for Chemical Ecology


Spodoptera littoralis larva feeding on a Arabidopsis thaliana (thale cress) plant

Sandra Scholz and Monika Heyer / Max Planck Institute for Chemical Ecology

Scientists of the Max Planck Institute for Chemical Ecology in Jena and the Institute of Agricultural and Nutritional Science of the Martin Luther University in Halle-Wittenberg, Germany, have now succeeded in visualizing the immediate wound or herbivory responses in plants.

They used Arabidopsis thaliana (thale cress) plants that produce a special protein which breaks down after the binding of calcium ions and emits free energy in the form of light. The amount of light corresponds to the calcium concentrations in the cells of the respective leaf areas. By using a highly sensitive camera system the researchers could track the calcium flow in the plants.

Visualization revealed that calcium signals occur systemically and wander from attacked to neighboring leaves within a short period of time, and ultimately put the whole plant into a state of defense readiness. (New Phytologist, May 2015)

Calcium is a universal intracellular messenger. In plants, many physiological processes are mediated by calcium ions, especially responses to abiotic and biotic stresses, such as feeding caterpillars. These trigger the activation of a number of defense mechanisms. If a leaf is attacked by an insect, the wound signal which emanates from the affected leaf is transmitted to other, unattacked leaves.

In order to visualize this signal, the scientists performed experiments with transgenic Arabidopsis plants which were genetically modified to express a protein in the cytosol, the liquid inside the cells, which breaks down and releases light energy after it has bound calcium ions. The emitted light energy correlates with the respective concentrations of calcium ions.

In this way, intracellular changes of calcium levels can be determined directly. Moreover, these processes can be made visible in the plants by applying a highly sensitive camera system which uses charge-coupled devices (CCD). “It is very impressive to see how every bite of a caterpillar makes certain leaf areas shine. The immediate reaction of the plants is clearly visible,” says Victoria Kiep, who carried out most of the experimental work together with Jyothilakshmi Vadassery.

It was very important for the researchers to show that the calcium signal is a systemic process, rather than a local one, as it wanders from the attacked leaf to neighboring leaves within a few minutes to trigger the subsequent defense responses. “We succeeded in visualizing the dynamic signal processing of intracellular calcium as a secondary messenger which is elicited by insect feeding and transmitted systemically to unattacked areas of the plant,” Axel Mithöfer, the leader of the project group “Physiology of Plant Defense” in the Department of Bioorganic Chemistry, summarizes the results of the study.

How calcium signals are elicited in different and separate areas of plants is not yet fully understood. However, the scientists speculate that electric signals which are transmitted via the vascular system of plants, so-called vascular bundles, play an important role. There are no important differences between calcium signals which are elicited by mechanical wounding and those which are triggered by feeding caterpillars. Surprisingly, the application of larval oral secretions inhibited the transduction of calcium signals to neighboring leaves in the experiment. Of general importance for systemic calcium signaling is the wounding of the vascular system of the leaf, which is also responsible for the internal transport of water and nutrients in the plant.

Further experiments are planned in order to find out which kind of wounding triggers the systemic calcium signal, for example, whether a similar wound response is elicited by aphids and spider mites, as these insects puncture the plant tissue to suck the plant sap and damage the tissue only slightly. The scientists would like to investigate how signal transduction is achieved in grasses whose vascular bundles are structured differently in comparison to Arabidopsis which belongs to the Brassicaceae family. They are also interested in determining the operating distance of calcium signals in general and would like to answer the question whether the signals can be transmitted to the plant roots.

This study demonstrates that calcium signals, which are necessary for eliciting plant defense responses, and their spatial and temporal expansion can be visualized. Moreover, the scientists showed that calcium signaling can be studied directly in intact plants in different physiological and ecological contexts, which helps to better understand its role as a secondary messenger in plants. [AO/AM]

Original Publication:
Kiep, V., Vadassery, J., Lattke, J., Maaß, J.-P., Boland, W., Peiter, E., Mithöfer, A. (2015). Systemic cytosolic Ca2+ elevation is activated upon wounding and herbivory in Arabidopsis. New Phytologist. doi: 10.1111/nph.13493
http://dx.doi.org/10.1111/nph.13493

Further Information:
Dr. Axel Mithöfer, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Tel. +49 3641 57-1263, E-Mail amithoefer@ice.mpg.de

Contact and Picture Requests:
Angela Overmeyer M.A., Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07743 Jena, +49 3641 57-2110, E-Mail overmeyer@ice.mpg.de

Download von hochaufgelösten Fotos über http://www.ice.mpg.de/ext/downloads2015.html

Weitere Informationen:

http://www.ice.mpg.de/ext/1214.html
http://www.ice.mpg.de/ext/520.html (Research Group Defense Physiology)

Angela Overmeyer | Max-Planck-Institut für chemische Ökologie

More articles from Life Sciences:

nachricht Not of Divided Mind
19.01.2017 | Hertie-Institut für klinische Hirnforschung (HIH)

nachricht CRISPR meets single-cell sequencing in new screening method
19.01.2017 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>