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2014-12 Desertcereals

Desert Cereals
The agriculture of the future has to be sustainable. We do research for cereals that can cope better with water scarcity.

The agriculture of the future has to be sustainable. The economic use of the precious resource water is central in this context. In a project funded by the Federal Ministry for Education and Research (BMBF) and the Egypt Science and Technology Fund we work for improved drought tolerance in rice and wheat.

Starting point is our collection of rice mutants, where jasmonic acid, a central stress Hormone, cannot be produced. To our surprise, These mutants were better adapted to salt and drought stress. Together with colleagues at the Agricultural Genetic Engineering Research Institute in Egypt we want to make use of these mutants to identify the genes underlying this improved adaptation. When these genes are known, it will become possible to introduced these gene variants by so called smart breeding into current varieties of rice and wheat. This procedure does not rely on transgenic engineering, but employs the natural sexuality of plants, i.e. classical crossing, after old varieties, landraces or wild relatives have been screened for the presence of the favourable gene variant. The molecular knowledge generated during this project will therefore make it possible to breed drought-tolerant varieties much faster than previously, when the breeder did not know, which gene was responsible for the desired trait.

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2014-07 A grammar of stress signals? (Plant Stress)

Signatur
The "meaning" of the signal jasmonate changes depending on the timing.

What is the topic?

Plants are masters in overcoming adverse conditions, which requires to discriminate between different types of stress. Surprisingly, different stress types do not use different signals, but plants use just a handful of molecules to transduce completely different signals. Actually, this resembles human language  - by combination few words can generate a multitude of meanings. However, this requires that certain rules (these rules are that what commonly is termed as grammar of a language) are maintained to render the signal intelligible. Is there something like a Grammar of Plant Stress Signalling? This work demonstrates, using plant adaptation to salt stress as example, how the meaning of the signal jasmonic acid mutates depending on the temporal context with other stress signals (i.e. depending on the grammar). Depending on timing, plants use one molecule to choose the best strategy (activation of salt pumps versus necrotic death of salt-polluted tissue).

Publication

[35] Ismail A, Takeda S, Nick P (2014) Life and death under salt stress: same players, different timing? J Exp Bot 65, 2963-2979 - pdf


2014-04 Red Light Soothes Plant Pain

Pflanzenschmerz
When plants are wounded, they respond by formation of jasmonic acid. Red light can quell this chemical cry for help.

What is the topic?

Plants do not scream. This does not mean that they do not know pain. They respond to wounding by formation of the alarm signal jasmonic acid. By means of a mechanical caterpillar that allows to administer wounding in a standardised manner, team member Rita Brendel investigated, how young rice plants respond to pain. She could show that phytochrome (a protein, that allows plants to perceive red light) can sooth the wound reaction. This allows plants to steer their wound response depending on day time - plants scream louder in the dark...

Publication

 

106. Brendel R, Svyatyna K, Jikumaru Y, Reichelt M, Mithöfer A, Takano M, Kamiya Y, Nick P, Riemann M (2014) Effects of light and wounding on jasmonates in rice phyAphyC mutants. Plants 3, 143-159 - pdf


2014-03 Grapes for the Desert

Reben für die Wüste
How to protect grapes against drought and salty soil? The stress hormone jasmonate plays a central role here.

Worum geht es?

Weinreben zählen zu den ersten Früchten, die der Mensch in Kultur nahm und es gibt wenig Kulturpflanzen, die mehr Geld pro Fläche einbringen. Ägypten versucht daher, den Anbau von Weinreben aus dem dicht besiedelten Niltal in die Wüstenränder hinaus auszudehnen. Dies geht nur mit Reben, die Trockenheit und versalzten Böden trotzen können. Unser Mitarbeitern Dr. Ahmed Ismail hat daher untersucht, wie Weinreben mit Salzstress umgehen. Er verglich dabei die trockenresistente Felsenrebe mit der anfälligen Uferrebe. Wie erwartet, aktivierte die Zellen in Antwort auf den Salzstress mit einer starken Erhöhung des Alarmhormons Jasmonsäure und seinem aktiven Konjugat Jasmonat-Isoleucin. Überraschend war jedoch, dass dieser Alarm bei der Uferrebe aus dem Ruder lief, bis die Zellen schliesslich erschöpft starben. Bei der Felsenrebe wurde der Jasmonatalarm jedoch sehr schnell wieder abgeschaltet und stattdessen das schützende Hormon Abscisinsäure gebildet. Es kommt also auf den Zeitpunkt an, ob eine Alarmreaktion schützt oder schädigt.

Veröffentlichung

104. Ismail A, Seo M, Takebayashi Y, Kamiya Y, Eiche E, Nick P (2014) Salt Adaptation Requires Efficient Fine-tuning of Jasmonate Signaling. Protoplasma 251, 881-898 - pdf