Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Breeding Salt-Tolerant Plants

10.10.2017

The quinoa plant might serve as a model for making other crops salt-tolerant. It grows well on saline soils because the excess salt is simply dumped into special bladders on its leaves.

Soil erosion is considered as a problem that puts the nutrition of the human population at jeopardy. One of its aspects is soil salination, which affects in particular dry regions of the earth, where farmers are forced to irrigate their fields heavily.


Quinoa leaf with typical salt bladders. Right, you see the plant transporting the dissolved salts into the bladder and then in its vacuoles. The sugar carried along provides the necessary energy.

Picture: Jennifer Böhm

Large quantities of the salts dissolved in the water, such as sodium and chloride, are diffused into the soil and remain there after the water has evaporated. The salt stunts the crops and can even make soils infertile in the long run.

“All approaches so far to breed salt-tolerant plants must be considered more or less as failures”, says Professor Rainer Hedrich, plant scientist at the Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany. They all aimed at making crop plants grow on saline soils and to identify salt-tolerant breed lines in the process. But this approach cannot work.

And that is for a reason: “Our crop plants are the result of many years of breeding. During that time, man has sheltered them from nearly all negative environmental influences, so that they have lost a lot of their natural resilience”, explains Hedrich. “As soon as these elite lines come in contact with too much salt, they usually die.”

Salt-tolerant plants serve as model

So Rainer Hedrich, together with Professor Sergey Shabala (University of Tasmania), set out to develop a new strategy. The two scientists placed their bet on plants that are naturally salt-tolerant.

One such plant is quinoa (Chenopodium quinoa). It comes from the Andes, where it has been been used as food for 7,000 years. Meanwhile the seeds of this South American pseudo-cereal, which are free from gluten and rich in vitamins, have found their way to European supermarket shelves.

The plant absorbs salt from the soil and stores it in bladder-shaped cells on the surface of its leaves. This protects the salt-sensitive metabolic processes, and the plant can grow well even on saline soils.

Without bladder cells quinoa suffers from salt stress

The researchers have found a simple way of proving that it is really the bladder cells that ensure the plant’s salt tolerance. “Just a few light brush strokes over a quinoa leaf cause the bladder cells to fall off”, says Professor Shabala. Stripped of their salt bladders, these plants grow on non-saline soils just as well as non-brushed specimens. But an exposure to common salt stunts their growth significantly.

The round to oval bladder cells of quinoa have a diameter of almost half a millimeter. They are veritable giants in the kingdom of plants, and can usually be seen even with the naked eye. Their storage capacity is up to 1000 times higher than that of any normal cell of the leaf surface.

The price of salt disposal is sugar

To get an insight into the “operating system” of quinoa and its bladder cells, the work group of Professor Jian-Kang Zhu (University of Shanghai) has decoded the Andes cereal’s DNA. Professor Hedrich’s team then compared the active genes of leaves and bladder cells. The necessary bioinformatic analyses were performed by experts from the University of Shanghai and from the team of Georg Haberer from the Helmholtz Center Munich.

The result: Even without salt treatment, there are genes working in the bladder cells which are in other species only active when the plant is under stress. They include transporters carrying sodium and chloride ions into the bladder cell. A stimulation with salt triggers the activation of further genes needed to maintain the signal path for the stress hormone ABA.

Storing the salt consumes energy. This energy is generated by the bladder cells from sugar molecules which they specially import from the leaf for that purpose. The bladder cells receive the required energy from the leaf and reciprocate by absorbing the toxic salt”, explains Hedrich.

Crossbreeding salt tolerance into crop plants

The new findings have been published in the “Cell Reports” journal. They are to be used in the long term for the breeding of salt-tolerant plants. “The first step is made”, says Professor Hedrich. “We will now use a combination of developmental genetics and the functional analysis of salt transport proteins to understand the molecular mechanisms that produces and maintains the salt tolerance in quinoa.”

The JMU research team wants to learn from quinoa lines equipped with a very large or a very low number of salt bladders. It has a large pool to draw on: about 2000 wild and cultivated varieties of the plant from the Andes are known so far. The ultimate outcome of their work might be not only the breeding of quinoa varieties with an even higher salt tolerance but also the crossbreeding of salt tolerance genes into related crop plants such as sugar beets or spinach.

“A high-quality genome assembly of quinoa provides insights into the molecular basis of salt bladder-based salinity tolerance and exceptional nutritional value". Heng Zhang, Changsong Zou, Aojun Chen, Lihong Xiao, Meiling Zhang, Wei Jia, Ping Deng, Ru Huang, Feng Li, Jian-Kang Zhu, Heike Muller, Peter Ache, Rainer Hedrich, Georg Haberer, Xiangyun Wu, Hui Zhang, Jennifer Bohm, Sergey Shabala, Renyi Liu, Daniel Lang, and Dongliang Zhan, Cell Reports doi:10.1038/cr.2017.124

Contact

Prof. Dr. Rainer Hedrich, Chair of Molecular Plant Physiology and Biophysics, Biocentre, JMU, T +49 931 31-86100, hedrich@botanik.uni-wuerzburg.de

Gunnar Bartsch | Julius-Maximilians-Universität Würzburg
Further information:
http://www.uni-wuerzburg.de

More articles from Life Sciences:

nachricht Multifunctional Platform for the Delivery of Gene Therapeutics
22.01.2018 | Angewandte Chemie International Edition

nachricht Charge Order and Electron Localization in a Molecule-Based Solid
22.01.2018 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Multifunctional Platform for the Delivery of Gene Therapeutics

22.01.2018 | Life Sciences

The world's most powerful acoustic tractor beam could pave the way for levitating humans

22.01.2018 | Power and Electrical Engineering

Siberian scientists learned how to reduce harmful emissions from HPPs

22.01.2018 | Power and Electrical Engineering

VideoLinks