Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Specialized plant cells regain stem-cell features to heal wounds

03.05.2019

Already specified root cells are reprogrammed to correctly replace dead neighbor cells in newly discovered process of “restorative patterning” | Study published in Cell

If plants are injured, cells adjacent to the wound fill the gaps with their daughter cells. However, which cells divide to do the healing and how they manage to produce cells that match the cell type of the missing tissue has been unclear.


A root tip consists of constantly dividing cells of specific types which originate from a few stem cells in the stem cell niche located in the very tip of the root (white cells).

IST Austria/Lukas Hörmayer

Scientists from the Institute of Science and Technology Austria (IST Austria) have now shown that to correctly replace dead cells, neighbors to the inside of the wound re-activate their stem cell programs.

All plant organs—from the leaves to the root—regularly endure injuries to their tissue, be it due to mechanical forces, grazing animals, or other factors. While animals rely on specialized migrating cells for wound healing, plants, whose cells are immobile, had to evolve other mechanisms:

It has been known for almost a century that in plants, cells adjacent to the wound replace harmed tissue with new daughter cells. Yet, a completely new aspect of plant wound healing in the sensitive root tip has only been discovered now:

The research team around first authors Petra Marhava, former PhD student at IST Austria, current PhD student Lukas Hörmayer, and former IST postdoc Saiko Yoshida—all three of them in the group of Jiří Friml—has found out that injured or destroyed root cells are not simply replaced by a proliferation of healthy cells from the same cell type above and below to the wound.

Instead, specifically the cells adjacent to the inner side of the injury reactivate their stem cell programs to produce de novo cells of the correct type to replace missing neighbors. The researchers termed this newly discovered process “restorative patterning”, involving “restorative cell division”.

The missing neighbor: Tissue gaps activate division of “healing cells” in adjacent tissue
With a UV laser, Marhava et al. removed individual cells or small cell groups in the root tip of the model plant Arabidopsis thaliana. Live imaging via the innovative vertical stage microscope—developed in a previous project at IST Austria—allowed them to track the wound healing process in vivo.

Restorative patterning could be observed in various specified tissue layers: epidermis, cortex, endodermis, and in innermost pericycle cells encircling the vascular tissue. In all tissue layers, the restorative patterning started with the division of the inner adjacent cells in response to a damaged or missing neighbor cell.

However, compared to regular proliferative divisions, the cell cycle of these “healing cells” happened significantly faster and included a shift of division planes by 90 degrees, allowing the cells to arrange perpendicular to the root axis (for the root to grow in length, root tip cells usually arrange parallel to the root axis).

Identity switch: Daughter cell of different type than mother cell

After cell division was complete, genetic marking showed that the resulting cell types matched those of the missing cells. For example, if a missing cortex cell was to be replaced by a newly generated daughter cell from an adjacent endodermis cell, this daughter cell acquired the new and “correct” cell type of a cortex cell.

Thus, activated “healing cells” are able to divide asymmetrically, i.e. they generate daughter cells of a different type than the mother cell—a process that typically only occurs in the root’s stem cell niche, the region where stem cells emanate from.

The roots of curiosity: Next generation scientist is looking closely at plant growth processes

How a stem cell program—i.e. transcription factors and the corresponding genes guiding restorative cell division including the switch of the division plane orientation—in an already specialized cell is activated, remains unknown. However, for Lukas Hörmayer, this study is only the beginning—not only as this paper is his first publication during his PhD program at IST Austria:

“We are convinced that in further studies, molecular genetics, among other methods, will reveal not only a broader understanding of the underlying mechanisms of plant wound healing, but also, how plants establish and maintain their body patterns.” Having grown up on a winery in Lower Austria, plants have always fascinated the young scientist: “This is a look far into the future, but the mere thought of what other discoveries beyond present knowledge my plant root research may bring about, drives my curiosity,” Hörmayer concludes.

The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement n° 742985, Marie Curie Fellowship (contract 753138) and from the Federation of European Biochemical Societies (FEBS) Long-Term Fellowship.

IST Austria
The Institute of Science and Technology (IST Austria) is a PhD-granting research institution located in Klosterneuburg, 18 km from the center of Vienna, Austria. Inaugurated in 2009, the Institute is dedicated to basic research in the natural and mathematical sciences. IST Austria employs professors on a tenure-track system, postdoctoral fellows, and doctoral students. While dedicated to the principle of curiosity-driven research, the Institute owns the rights to all scientific discoveries and is committed to promote their use. The first president of IST Austria is Thomas A. Henzinger, a leading computer scientist and former professor at the University of California in Berkeley, USA, and the EPFL in Lausanne, Switzerland. The graduate school of IST Austria offers fully-funded PhD positions to highly qualified candidates with a bachelor's or master's degree in biology, neuroscience, mathematics, computer science, physics, and related areas.

www.ist.ac.at

Wissenschaftliche Ansprechpartner:

Jirí Friml
jiri.friml@ist.ac.at

Originalpublikation:

Petra Marhava, Lukas Hörmayer, Saiko Yoshida, Peter Marhavý, Eva Benková & Jiří Friml. 2019. Re-activation of stem cell pathways for pattern restoration in plant wound healing. Cell. DOI: 10.1016/j.cell.2019.04.015
https://www.cell.com/cell/fulltext/S0092-8674(19)30401-5

Weitere Informationen:

https://ist.ac.at/en/research/life-sciences/friml-group/ Website of the research group

Dr. Elisabeth Guggenberger | idw - Informationsdienst Wissenschaft

Further reports about: cell division cell type daughter cells plant cells root wound healing

More articles from Life Sciences:

nachricht Human skin is an important source of ammonia emissions
27.05.2020 | Max-Planck-Institut für Chemie

nachricht Biotechnology: Triggered by light, a novel way to switch on an enzyme
27.05.2020 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

German-British Research project for even more climate protection in the rail industry

28.05.2020 | Transportation and Logistics

A special elemental magic

28.05.2020 | Physics and Astronomy

Skoltech scientists get a sneak peek of a key process in battery 'life'

28.05.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>