Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pump! And you will grow

28.07.2014

Phosphate transport from fungi to plant roots requires a proton pump

Phosphorous (P) is a component of DNA and plays an important role in energy metabolism; therefore it is essential for all organisms. Plants are able to take it up from the soil in the form of salts, namely phosphates.


Arbuscular mycorrhizal structures in a root stained in blue and magnified with a light microscope.

Max Planck Institute of Molecular Plant Physiology

But in many soils phosphate is already depleted and the world’s phosphate resources, which can be used to produce fertilizer, are declining. Nevertheless, crop plants need an optimal P-supply to gain high yields. To overcome this problem, a special community of plants and fungi could become more important in the future.

About 80 % of all land plants live in a kind of marriage with arbuscular mycorrhizal fungi. This relationship secures the plants’ phosphate nutrition while the fungi are rewarded with sugars. Scientists around Franziska Krajinski from the Max Planck Institute of Molecular Plant Physiology recently discovered that a special proton pump facilitates the transport of fungal phosphate into the plant. (Plant Cell, DOI: 10.1105/tpc.113.120436).

It is all about give-and-take

This relationship, or better symbiosis, is an ancient story of success; arbuscular mycorrhizal fungi (AM fungi) already supported plants in the initial colonization of land over 400 million years ago. In contrast to other fungi, like the yellow boletus, AM fungi are not visible above-ground. They enter the roots of plants with their hyphae and build treelike structures called arbuscules. This name derives from the Latin phrase “arbusculus”, meaning “little tree”.

When one partner lives inside the other, this is called an endosymbiosis and, as in all well working relationships, this symbiosis positively affects both partners. The plant receives phosphate from the fungus in exchange for sugars.

Nothing works without energy

The scientists around Franziska Krajinski from the MPI-MP are interested in the transport processes between the AM fungus Rhizophagus irregularis and the barrel clover Medicago truncatula. Although AM fungi live inside the root cells of their symbiotic partners, both are always separated from each other by two membranes – the fungal membrane and the so-called periarbuscular membrane, on the plant side.

Phosphate has to cross those barriers on its way from the fungus to the root cell. In the periarbuscular membrane, this is facilitated by certain proteins, that transport their cargo from the fungus to the plant like little trucks and just like the real trucks they need energy to do their job. “But, proteins cannot stop at a petrol station to refuel with energy. They have to use other resources”, Daniela Sieh comments on the current research.

“We wanted to unravel the energy source of phosphate transport. Luckily, we could refer to older studies, where we identified a gene in barrel clover, which encodes a proton pump”, Prof. Franziska Krajinski adds.

Just like the transport proteins mentioned above, this proton pump is localized in the periarbuscular membrane. There, it transports protons - small positively charged hydrogen ions – into the space between the periarbuscular and the fungal membrane. This leads to a higher concentration of protons on the outside of the plant cell than on the inside, a so-called proton gradient. The protons on the outside serve as energy source for the transport of phosphate into the plant cell.

No proton pump – no phosphate

To prove that this proton pump is required to transport phosphate, the scientists generated Medicago truncatula mutants that have a non-functional version of the respective gene. Thus, the proton pump cannot be synthesized correctly. The symbiotic phosphate uptake and the growth rate of those mutants were compared to wild type plants. Roots of both plants - mutant and wild type - were equally colonized by Rhizophagus irregularis. Nevertheless, under phosphate deprivation the wild type plants grew better than the mutants due to the extra P-supply from the fungus

The scientists also compared the phosphate transport to different parts of the plants. Wild type plants incorporated fungal phosphate in roots and shoots, as usual for mycorrhizal symbiosis. But, this pattern of phosphate incorporation could not be observed for the mutants. “We discovered that the proton pump is essential for phosphate transport”, Franziska Krajinski says, “The mutants could not grow on phosphate depleted soil, although they were colonized by the fungus”. Considering the declining phosphate resources, it is crucial to build a better understanding of symbiotic processes. The use of mycorrhizal products as replacement for mineral fertilizers is restricted to organic farming at the moment. Though, this will probably get increasingly important for the nutrition of crop plants and our own nutrition as well in the future.

KD/URS

Contact

Prof. Dr. Franziska Krajinski
Max Planck Institute of Molecular Plant Physiology
Tel. 0331/567 8360
Krajinski@mpimp-golm.mpg.de

Dr. Kathleen Dahncke
Press and Public Relations
Max Planck Institute of Molecular Plant Physiology
Tel. 0331/567 8275
dahncke@mpimp-golm.mpg.de

Weitere Informationen:

http://www.mpimp-golm.mpg.de/8316/2krajinski Prof. Dr. Krajinski's Website
http://www.plantcell.org/content/early/2014/04/29/tpc.113.120436.abstract?sid=0e... Orignial publication

Ursula Ross-Stitt | Max-Planck-Institut

Further reports about: Max-Planck-Institut Molecular Physiology fungal fungi fungus mutants mycorrhizal phosphate proteins protons pump symbiosis symbiotic

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>