Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Regulation of root growth from afar: How genes from leaf cells affect root growth


Plants possess diverse and complex communication channels, with good reason. Communication errors or "false news" could in the worst-case result in the plant dying. A team of scientists from the Max Planck Institute of Molecular Plant Physiology, in collaboration with international cooperation partners, has discovered a completely new mechanism of internal communication that is used by plants.

Anyone who believes that plants are organisms "without brains" that lack the ability to perceive and respond to the environment is wrong. Plants exhibit tremendous variety and grow in many different locations, and this requires enormous adaptability.

Grafted Arabidopsis plant

Grafts of genetically different plants have long been used, for example, in grapevines and fruit trees, to combine characteristics of one plant with characteristics of the other.

In the experiments of the present study, two different genotypes of Arabidopsis were grafted onto each other. By fusing a non-mobile mRNA producing a green fluorescent protein to a graft mobile mRNA from a gene that is transcribed only in the plant used for the upper part (shoot), mRNA transport from this Arabidopsis type can be traced across the grafting site into the roots, which do not produce this transcript. Here the mRNA fusion is translated into the corresponding protein in the root cells, which then appear green fluorescent, as can be seen in the figure.

© MPI-MP, Kragler

They have an amazing capacity for internal communication, which allows them to coordinate their development and growth. Decisions are needed on whether new leaves should be produced to allow more photosynthesis, or root growth should be increased to provide a larger root surface, occupy more soil and access more water and nutrients, or defense molecules should be produced to combat viruses, bacteria, fungi or other attackers, or whether it is time to flower and set seed.

To reach the right decision and coordinate tasks in an error-free manner requires correct recording and registration of environmental signals, production of appropriate internal signals, transport of these signals into the relevant parts of the plant and their subsequent processing, feedback and verification at their site of action.

Errors in signal generation and processing or in internal communication can in the worst-case lead to the immediate death of the plant and must be avoided at all costs. Therefore, plants have diverse and complex communication channels.

Scientists from the Max Planck Institute of Molecular Plant Physiology together with colleagues from France, Italy, Hong Kong and China have shown a new way in their current study. They demonstrated that root regulation can be controlled by mobile interpreters with special characteristics.

Communication from the leaf to the root over the sieve tubes

Normally, it is assumed that after a gene is activated, the corresponding protein is produced in the same cell. When a gene is activated, the corresponding DNA sequence is read off - transcribed - to generate a transient RNA copy that acts as an interpreter; the so-called messenger or mRNA.

The mRNA moves from the nucleus into the cytoplasm, where it is translated into proteins at the ribosomes. The proteins are the important actors for a living being. Their nature, composition and structure essentially determine the characteristics of an organism and ensure that organisms develop and grow.

However, it has been known some time that in plants mRNA does not necessarily remain in the cells where the gene is read-off, but that it can be transported over long distances to other parts of the plant. Dr. Friedrich Kragler, working group leader at the MPI-MP, could already show in an earlier publication that about 2000 genes produce so-called mobile mRNAs.

Transport of these mRNAs takes place in the sieve tubes (phloem) of the plants, in which sugar and other organic materials are transported. So far, little was known about how a mRNA molecule is converted into a mobile transport form. As summarized by Dr. Kragler, "In our current work we have not only been able to demonstrate that certain mRNA molecules are transported from the leaves into the roots to stimulate root growth, but we also uncovered the mechanism responsible for mobilizing the mRNA, and demonstrated that the protein is actually formed at the target site".

How short-distance interpreters are turned into long-distance informants

The mechanism by which the mRNA is turned into a mobile interpreter between leaves and roots involves a chemical modification of one of the basic building blocks in the mRNA.

Analogous changes have long been known to occur in DNA, the molecule in which the genetic information is stored. In DNA, such modification allow the inheritance of new properties, without the need for a mutation in the genetic material itself.

This mechanism involves the transfer of methyl groups onto the cytosine bases of the DNA. This changes the activity of individual genes or even of whole chromosomes. These changes are called epigenetic effects.

As Dr. Kragler explains: "We were able to demonstrate for the first time that cytosine-based methylation also has a function in mRNA. This modification results in certain mRNA molecules produced in leaves being transported via the phloem to the root. These mRNAs are transported to specific root cells and translated into functional proteins. That in turn regulates root growth".

The reason for the regulation from a distance is probably that in this way leaf and root growth can be coordinated. If a plant does not have enough roots, the leaves are not supplied with enough nutrients and growth is slowed down.

On the other hand, if the plant forms too many roots, then the aboveground plant part receives more nutrients than it needs, but the growth may still be slowed down because too much energy is put into the root growth and too little remains for aboveground growth.

Specific regulatory mobile mRNAs could help to ensure that root growth matches the nutritional needs of the leaves, thus making the most efficient use of the energy gained from photosynthesis. In the next step, the scientists will investigate why only certain mobile mRNA molecules are modified.

Wissenschaftliche Ansprechpartner:

Dr. Friedrich Kragler
Max-Planck-Institut für Molekulare Pflanzenphysiologie
Tel. 0331/567 8165


Lei Yang, Valentina Perrera, Eleftheria Saplaoura, Federico Apelt, Mathieu Bahin, Amira Kramdi, Justyna Olas, Bernd Mueller-Roeber, Ewelina Sokolowska, Wenna Zhang, Runsheng Li, Nicolas Pitzalis, Manfred Heinlein, Shoudong Zhang, Auguste Genovesio, Vincent Colot, and Friedrich Kragler
m5C methylation guides systemic transport of messenger RNA over graft junctions in plants
Current Biology, 18.07.2019,

Dipl. Ing. agr. Ursula Ross-Stitt | Max-Planck-Institut für Molekulare Pflanzenphysiologie
Further information:

More articles from Life Sciences:

nachricht Family of crop viruses revealed at high resolution for the first time
15.10.2019 | John Innes Centre

nachricht Receptor complexes on the assembly line
15.10.2019 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

Im Focus: How Do the Strongest Magnets in the Universe Form?

How do some neutron stars become the strongest magnets in the Universe? A German-British team of astrophysicists has found a possible answer to the question of how these so-called magnetars form. Researchers from Heidelberg, Garching, and Oxford used large computer simulations to demonstrate how the merger of two stars creates strong magnetic fields. If such stars explode in supernovae, magnetars could result.

How Do the Strongest Magnets in the Universe Form?

All Focus news of the innovation-report >>>



Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

Latest News

Strong storms generating earthquake-like seismic activity

16.10.2019 | Earth Sciences

New material captures carbon dioxide

15.10.2019 | Materials Sciences

Drugs for better long-term treatment of poorly controlled asthma discovered

15.10.2019 | Interdisciplinary Research

Science & Research
Overview of more VideoLinks >>>