Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plant size morphs dramatically as scientists tinker with outer layer

09.03.2007
Jack's magical beans may have produced beanstalks that grew and grew into the sky, but something about normal, run-of-the-mill plants limits their reach upward.

For more than a century, scientists have tried to find out which part of the plant both drives and curbs growth: is it a shoot's outer waxy layer? Its inner layer studded with chloroplasts? Or the vascular system that moves nutrients and water? The answer could have great implications for modern agriculture, which desires a modern magical bean or two.

Now, in the March 8 issue of the journal Nature, researchers in the Plant Biology Laboratory at the Salk Institute for Biological Studies provide the answer. They succeeded in making tiny plants big and big plants tiny by controlling growth signals emanating from the plant's outer layer, its epidermis.

These findings could eventually be used by agronomists to manipulate plant growth pathways to maximize crop yield, or even reduce leaf size or leaf angle in plants that need to be spaced closely together, says the study's lead author, Joanne Chory, Ph.D., professor and director of the Plant Biology Laboratory and investigator with the Howard Hughes Medical Institute.

... more about:
»Arabidopsis »BRI1 »Epidermis »Steroid »dwarf

Chory and her laboratory team have spent years helping to define how a plant "knows" when to grow and when to stop – which is a "big question in developmental biology," she says. For their experiments, they rely on the model system Arabidopsis thaliana, a small plant related to cabbage and mustard whose genome has been decoded. Over the years, the researchers have built up a whole tool kit, learning how to add and subtract genes in order to determine form and function. Among their discoveries is a class of dwarf plants whose size is about one-tenth the size of a single leaf of the full-sized plant.

Over the past decade, Chory's laboratory and others have shown that these dwarf plants are defective in making or responding to a steroid hormone called brassinolide. Among the genes identified was the plant steroid receptor, BRI1 ("bry-one") that is activated by the steroid. The dwarfed Arabidopsis doesn't express BRI1 at all, unlike normal Arabidopsis, which expresses BRI1 on both the outer waxy, protective epidermis (covering the whole leaf and shoot), and the inner sub-epidermal layer, which contains the chloroplasts that conduct photosynthesis.

In the current study, first author Sigal Savaldi-Goldstein, Ph.D., a postdoctoral researcher in the Plant Biology Laboratory, and Charles Peto, an electron microscopy specialist in the Laboratory of Neuronal Structure and Function, conducted a series of experiments that addressed an old debated question: what tissues of the leaf drive or restrict growth? The answer was simple: the epidermis is in control.

They found that when they drive the expression of the BRI1 receptor in the epidermis of a dwarf Arabidopsis, while leaving the sub-epidermal layer as it was (without BRI1 receptors), the tiny plant morphed into a full-sized plant. In the second set of experiments, they used an enzyme to break down the steroid hormones in the epidermis, and found that a normal sized plant shrunk into a dwarf. "These are simple experiments, but it took 10 years of work in order for us to be able to ask this question," Chory says.

"A second remarkable finding from the study is that "cells in the outer layer talk to the cells in the inner layers, telling them when to grow or to stop growing. This communication is very important to the life of a plant, which can't move and so must have a coordinated system to respond to a changing environment," explains Savaldi-Goldstein.

Gina Kirchweger | EurekAlert!
Further information:
http://www.salk.edu

Further reports about: Arabidopsis BRI1 Epidermis Steroid dwarf

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>