Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plant immunity comes at a price. An overzealous immune system can be deadly

21.11.2014

Plants are under permanent attack by a multitude of pathogens. To win the battle against fungi, bacteria and so on, they have developed an effective immune system. And just as in humans, this can also overshoot its target when some of the plant’s own proteins are mistakenly identified as foreign. Such autoimmune reactions can lead to tissue defects and growth arrest, and they are particularly apparent in hybrids.

Scientists from the Max Planck Institute for Developmental Biology in Germany have now pinpointed the most common culprits for autoimmunity. Surprisingly, these are components of the immune system itself, which are mistakenly recognized by other immune receptors as intruders.

Similar to the situation in animals, immunity in plants relies on highly variable immune receptors. "Not only do plants often have hundreds of so-called NLR immune genes, but each individual in a population tends to have its own collection of NLR genes, and is thus resistant against a unique spectrum of microbes, insects and worms ", explains Detlef Weigel, Director at the Max Planck Institute for Developmental Biology.

With this arsenal at hand, a plant can successfully defy a multitude of pathogens. Because each individual in a field has a different recognition spectrum, it is difficult for pathogens to wipe out the entire population. This great diversity can, however, also lead to accidents, such that a plant no longer reliably distinguishes between self and non-self and fights its own proteins. The misfortune occurs particularly often when two different immune systems are combined in the offspring of crosses.

To investigate the genetic basis of autoimmunity after crosses, the Max Planck scientists generated over 6400 crosses between natural strains of Arabidopsis thaliana. The parental lines were from different locations around the world and covered almost the entire genetic bandwidth of the species. The progeny of the crosses were then examined for evidence of autoimmunity.

Roughly every 50th cross led to typical autoimmune symptoms; in the most extreme cases, the progeny died already as seedlings and no longer reproduced. Because this occurred in the absence of pathogens, it must have been plant proteins that were mistakenly detected as foreign by the immune system of these hybrid plants. “Remarkably, the responsible proteins originated from only very few of the highly variable immune genes, even though Arabidopsis has more than a hundred of them”, says Eunyoung Chae, the lead author of the study.

Growth and defence in balance

According to Weigel, it was a surprise that certain combinations of immune genes are so often lethal. The causal variants presumably are advantageous on their own, normally providing resistance to pathogens without hurting the plant, but the wrong combinations can be detrimental. Still, the individual advantages must be sufficiently great, so that such variants can occur even in the same field.

The researchers suggest that the observed cases of autoimmunity in hybrids represent only the tip of the iceberg. "Because we applied strict criteria for classifying crosses as being associated with autoimmunity, it is likely that there are many other crosses where there is no apparent tissue damage, but still a growth penalty," explains Chae.

By systematically analysing which immune receptors are particularly dangerous and which combinations are best avoided, the Max Planck researchers hope to derive rules that will be useful in optimizing the trade-off between growth and defence, not only in wild plants such as Arabidopsis, but also in crops. Given the ever-increasing needs of a growing world population, streamlined ways to improve food crops are of great importance.

Participating researchers and institutions:
Eunyoung Chae, Kirsten Bomblies, Sang-Tae Kim, Darya Karelina, Maricris Zaidem, Stephan Ossowski, Carmen Martín-Pizarro, Roosa A. E. Laitinen, Beth A. Rowan, Hezi Tenenboim, Sarah Lechner, Monika Demar, Anette Habring-Müller, Christa Lanz and Detlef Weigel, Max Planck Institute for Developmental Biology, Tübingen;
Darya Karelina and Gunnar Rätsch, Friedrich Miescher Laboratory of the Max Planck Society, Tübingen.

Original Publication:
Chae et al.
A Species-wide Analysis of Genetic Incompatibilities Identifies NLR Loci as Hotspots of Deleterious Epistasis
Cell, Dec 4, 2014, http://dx.doi.org/10.1016/j.cell.2014.10.049

Nadja Winter | Max-Planck-Institut
Further information:
http://eb.mpg.de

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>