Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Plant growth hormones: antagonists cooperate

Stem cell researchers from Heidelberg and Tübingen elucidate complex interaction between auxin and cytokinin

The two most important growth hormones of plants, so far considered antagonists, also work synergistically. The activities of auxin and cytokinin, key molecules for plant growth and the formation of organs, such as leaves and buds, are in fact more closely interwoven than previously assumed.

Scientists from Heidelberg, Tübingen (Germany) and Umea (Sweden) made this surprising discovery in a series of complex experiments using thale cress (Arabidopsis thaliana), a biological reference organism. The international team of researchers, led by Prof. Dr. Jan Lohmann, stem cell biologist at Heidelberg University, have now published their results in the scientific journal “Nature”.

All the above-ground parts of a plant – leaves, buds, stems and seeds – ultimately arise from a small tissue at the shoot tip, which contains totipotent stem cells. Since plant stem cells remain active over the entire life of the organism, plants, unlike animals, are able to grow and develop new organs over many decades. On the periphery of the tip, auxin triggers cells to leave the pool of stem cells, differentiate and form organs like leaves and buds. Cytokinin stimulates stem cells to divide and proliferate; it maintains the number of cells and thus the plant’s growth potential.

Some of the genetic factors involved in cytokinin’s effect on plant growth were already known. In the thale cress experiments, which concentrated on the growth zone at the tip of the shoot, Lohmann and his team now studied the role of auxin in the interplay of the two hormones. It turns out that auxin directly interferes with a feedback loop involving two genes activated by cytokinin – ARR7 and ARR15 – which limit the effect of cytokinin. Auxin suppresses these two genes, thereby boosting the effect of cytokinin.

“Auxin acts to support the pool of stem cells”, explains Prof. Lohmann. “When it triggers cells at the periphery of the growth zone to form organs, it still needs to ensure that enough stem cells are supplied.” This keeps the number of stem cells from falling below a critical minimum, which is key for plant growth and survival. “We’re gradually beginning to understand how hormonal and genetic factors are interwoven to maintain the activity of the growth zone. We now know that hormones and genes interact in multiple ways, each one affecting the other. There are no solitary factors.”

In addition to Jan Lohmann, Zhong Zhao and Andrej Miotk from the Department of Stem Cell Biology at the Institute of Zoology at Heidelberg University, the team includes Stig U. Andersen and Sebastian J. Schultheiss from the Max Planck Institute for Developmental Biology and the Friedrich Miescher Laboratory in Tübingen, as well as Karin Ljung and Karel Dolezal of Sweden’s Umea Plant Science Center.

Original publication:
Z. Zhao, S.U. Andersen, K. Ljung, K. Dolezal, A. Miotk, S.J. Schultheiss, J.U. Lohmann: Hormonal control of the shoot stem-cell niche, Nature (24 June 2010), doi: 10.1038/nature09126
Prof. Dr. Jan Lohmann
Institute of Zoology
Phone: +49 6221 54-6269

Marietta Fuhrmann-Koch | idw
Further information:

More articles from Life Sciences:

nachricht North and South Cooperation to Combat Tuberculosis
22.03.2018 | Universität Zürich

nachricht Researchers Discover New Anti-Cancer Protein
22.03.2018 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Modular safety concept increases flexibility in plant conversion

22.03.2018 | Trade Fair News

New interactive map shows climate change everywhere in world

22.03.2018 | Earth Sciences

New technologies and computing power to help strengthen population data

22.03.2018 | Earth Sciences

Science & Research
Overview of more VideoLinks >>>