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 New application for acoustics helps estimate marine life populations
16.01.2018 | University of California - San Diego

nachricht Unexpected environmental source of methane discovered
16.01.2018 | University of Washington Health Sciences/UW Medicine

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

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

White graphene makes ceramics multifunctional

16.01.2018 | Materials Sciences

Breaking bad metals with neutrons

16.01.2018 | Materials Sciences

ISFH-CalTeC is “designated test centre” for the confirmation of solar cell world records

16.01.2018 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>