Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Plant hormone 'switch' unravels chromatin to form flowers, penn biologists find


Because plants cannot pick up and move, they have evolved a plethora of strategies to cope with environmental stresses, whether they bring a harsh spell of drought or a browsing deer.

One of these strategies is plants' ability to continue growing new, diverse organs, including roots, branches and flowers, throughout their lifespan. But of course flowers don't develop just anywhere on the plant; they only grow from certain cells, which must receive a particular signal to begin the process. While researchers knew that flower formation was governed by the activity of the hormone auxin, they didn't understand precisely how it signaled the plant to form blooms.

Instead of flowers, plants with mutations in certain chromatin remodeling genes developed pin-like structures (right).

Credit: University of Pennsylvania

Now University of Pennsylvania researchers have filled in the gaps and identified a hormone-mediated "chromatin switch" that directs a plant to form flowers. In the absence of auxin, genes that initiate flower formation are tucked away in tangled chromatin, a tightly packed bundle of DNA. But, in the hormone's presence, proteins are recruited to unravel chromatin and make the genes responsible for flower formation more accessible.

The findings could be useful in efforts to strategically boost flower formation as a means of increasing yield in agricultural crops. And the study's contribution to understanding basic mechanisms of chromatin regulation, which may be similar across species and even kingdoms of living things, could have implications for many biological processes, including human health.

... more about:
»flower »genes »hormone »proteins

"This one hormone auxin is very famous because it has many roles, in embryo, root and flower development, in vein formation, in growth -- it's doing all of these things," said Doris Wagner, senior author on the work and a professor of biology in Penn's School of Arts & Sciences. "The question is always, How can one hormone do all these different things? Now we see that, by helping open up chromatin, it can allow a variety of other proteins to come in and initiative these different pathways. All of a sudden these very diverse processes are not so hard to explain anymore."

Wagner collaborated with Penn's Miin-Feng Wu, Nobutoshi Yamaguchi, Jun Xiao and Yi Sang as well as Bastiaan Bargmann and Mark Estelle of the University of California, San Diego.

Their research is published in the journal eLife.

In work published in 2013, Wagner and colleagues began to piece together how auxin regulated flower formation. They already knew that auxin activated the transcription factor MONPTEROS, and went on to identify that factor's direct targets, which included three genes involved in flower development.

But the researchers believed the process was not that simple because those genes were packed tightly away in chromatin, which would prevent them from being activated. There must be another factor that makes those genes available to be transcribed, the team reasoned.

"So we looked on purpose for proteins that are required for making flowers and were also chromatin regulators that might overcome this repressive environment," Wagner said.

Performing experiments in Arabidopsis, the researchers showed that plants with double mutations in SWI/SNF proteins, BRM and SYD, which are known chromatin remodelers, failed to initiate flower formation. Because they can't make flowers, these plants had pointy "pin-like" forms.

The team also showed that BRM and SYD, which are part of a chromatin remodeling complex, bound to the same locations as MONOPTEROS does in the regulatory regions of various genes required for flower development. They also demonstrated that MONOPTEROS physically interacts with BRM and SYD, likely recruiting them to the proper site in the chromatin.

Once at the proper site, the team showed that BRM and SYD, in the presence of auxin, reshape chromatin in a way that makes the flower-formation genes more accessible for transcription and expression.

Wagner's group next artificially guided BRM and SYD to the correct locations in the genome in plant cells. Those cells showed increased expression of flower formation genes, just as cells exposed to auxin did.

When they repeated this experiment in a mutant plant that normally fails to form flowers, they were able to coax it to develop flowers, almost identically to a normal plant.

"We were very surprised to see the flowers come back so dramatically," Wagner said. "And, though we didn't study other aspects exhaustively, it appears that this chromatin-remodeling complex may also rescue leaf formation and perhaps some other plant development processes regulated by auxin."

The findings suggest that this process could be strategically manipulated in order to pack more flowers on one plant, potentially increasing agricultural yields.

There are signs that the auxin pathway and these SWI/SNF proteins are present even in ancient plants, so the process of recruiting chromatin remodelers could be universal in plants.

Auxin is not made in humans, but, as Wagner noted, the chromatin remodelers her team studied are and are known to be tumor suppressors -- proteins that, when mutated, can allow tumors to grow unchecked. Thus, it's conceivable that one could design a hormonal switch, using auxin, to regulate them.

Media Contact

Katherine Unger Baillie


Katherine Unger Baillie | EurekAlert!

Further reports about: flower genes hormone proteins

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>