Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plants adapt their defenses to the local pest community

05.10.2012
Populations of the same plant species produce specific defenses that are effective against the predominant local pest community.
Variation in the local pest community can therefore maintain genetic variation in plants across large geographical scales. Ecologists from the University of Zurich used controlled experiments coupled with observations on natural plant populations and their pests to demonstrate how genetic variation in plant defenses is maintained. The results could be used to develop customized seeds that are more resistant to the local pest community.

Populations of the same plant species produce specific defenses that are effective against the predominant local pest community. Variation in the local pest community can therefore maintain genetic variation in plants across large geographical scales. Ecologists from the University of Zurich used controlled experiments coupled with observations on natural plant populations and their pests to demonstrate how genetic variation in plant defenses is maintained. The results could be used to develop customized seeds that are more resistant to the local pest community.

Test set-up of the selection experiment. Different genotypes of Arabidopsis thaliana were exposed to different aphids in parallel. Each individual Plexiglas box simulates a plant population with a particular composition of aphids.

UZH


Detailed view of the selection experiment. Plant populations are harmed to varying degrees by the different aphid species. From left to right: Population without aphids, mustard aphid, cabbage aphid, aphid mixture, mustard aphid, peach aphid.

Herbivorous insects, such as aphids, damage plants and can substantially reduce yields in agricultural settings; however, they can play a major role in maintaining genetic diversity. Ecologists Tobias Züst and Lindsay Turnbull from the University of Zurich together with colleagues from California and Great Britain demonstrated the importance of variation in herbivore communities using the model plant, Arabidopsis thaliana, also known as wall cress. According to Züst, the work is one of the first experimental confirmations of a forty-year-old theory that herbivorous insects exert strong selective pressure on their host plants. Moreover, plants were quick to abandon defense mechanisms when pests were absent, confirming the high costs of these defenses.

Like many other plants, Arabidopsis thaliana, or wall cress, defends itself against pests with a sophisticated chemical arsenal. The pests, however, continually evolve mechanisms to tolerate or metabolize particular chemical components. This means that depending on the abundance of different pest species, different compounds will provide optimal protection, and thus the plant needs to produce a carefully tailored cocktail that will be effective against the most likely attackers. The researchers’ first step was to study the distribution of different chemical defenses in natural populations of Arabidopsis thaliana across Europe and compare it to the geographic distribution of two important pest species: the cabbage and the mustard aphid.

Local pest populations as an evolutionary force
The scientists demonstrate that the main chemical compounds produced by Arabidopsis thaliana in South-western Europe differ from those in North-eastern Europe. This pattern correlates directly with a shift in the composition of the aphid communities. In the second step, the researchers studied experimentally whether different aphid species could directly select for these different chemical compounds under controlled conditions. To this end, they exposed mixed populations of Arabidopsis thaliana to the cabbage and mustard aphid populations typical of North-eastern or South-western Europe. After five plant generations, continuous feeding by the different aphid species led to the selection of different chemical profiles, and these were consistent with the patterns seen in nature. “There is natural variation in chemical defenses which is under genetic control”, explains Züst “and this variation is maintained by geographic variation in the composition of aphid communities”. “Genetic variation is the raw material for evolution”, he continues, “so the maintenance of genetic diversity is essential if populations are to respond to future environmental changes such as climate change or environmental degradation”.
The costs of defense
In the control populations with no aphid feeding, some of the successful genotypes from aphid populations were lost. According to Turnbull, this occurred because defense mechanisms are costly for the plant and often come at the expense of growth: “Genetic diversity was only maintained across the different treatments; within each treatment much of the diversity was lost. In the control populations, this meant the loss of defended genotypes, as here investment in costly defenses brings no benefit to the plant”. Today, the genetic diversity of many plant species is being eroded. For example, agricultural plants are selected for rapid growth and maximum yield at the expense of natural defenses, making the use of pesticides inevitable. In future, the new findings could be used to develop customized seeds that are more resistant to specific local pest communities, thus limiting the use of pesticides.
Further reading:
Tobias Züst, Christian Heichinger, Ueli Grossniklaus, Richard Harrington, Daniel J. Kliebenstein, Lindsay Turnbull. Natural enemies drive geographic variation in plant defenses. Science. October 5, 2012, doi: 10.1126/science.1226397.
Contact:
Dr Tobias Züst
Department of Ecology and Evolutionary Biology
Cornell University
Phone +1 607 319 99 05
e-mail: tobias.zuest@cornell.edu
Dr. Lindsay Turnbull
Institute of Evolutionary Biology and Environmental Sciences
University of Zurich
Phone +41 44 635 61 20
e-mail: lindsay.turnbull@ieu.uzh.ch

Nathalie Huber | Universität Zürich
Further information:
http://www.uzh.ch

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

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

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>