Plants on Steroids: Key Missing Link Discovered

Sep 08, 2009

(PhysOrg.com) -- Researchers at the Carnegie Institution's Department of Plant Biology have discovered a key missing link in the so-called signaling pathway for plant steroid hormones (brassinosteroids). Many important signaling pathways are relays of molecules that start at the cell surface and cascade to the nucleus to regulate genes.

This discovery marks the first such pathway in plants for which all the steps of the relay have been identified. Since this pathway shares many similarities with pathways in humans, the discovery not only could lead to the genetic engineering of crops with higher yields, but also could be a key to understanding major human diseases such as cancer, diabetes, and Alzheimer's.

Steroids are important hormones in both animals and plants. Brassinosteroids regulate many aspects of growth and development in plants. Mutants deficient in brassinosteroids are often stunted and infertile. Brassinosteroids are similar in many respects to animal steroids, but appear to function very differently at the cellular level. Animal cells usually respond to steroids using internal within the cell nucleus, whereas in plants the receptors, called receptor-like kinases, are anchored to the outside surface of the cell membranes. For over a decade, scientists have tried to understand how the signal is passed from the cell surface to the nucleus to regulate . The final gaps were bridged in the study published in the advanced on-line issue of September 6, 2009.

The research team unraveled the pathway in cells of , a small flowering plant related to cabbage and mustard often used as a model organism in plant molecular biology.

"This is the first completely connected from a plant receptor-like kinase, which is one of the biggest gene families in plants," says Carnegie's Zhi-Yong Wang, leader of the research team. "The Arabidopsis genome encodes over 400 receptor-like kinases and in rice there are nearly 1,000. We know the functions of about a dozen or so. The completely connected brassinosteroid pathway uses at least six proteins to pass the signal from the receptor all the way to the nuclear genes expressed. This will be a new paradigm for understanding the functional mechanism of other receptor-like kinases."

Understanding the molecular mechanism of brassinosteroid signaling could help researchers develop strategies and molecular tools for genetic engineering of plants with modified sensitivity to hormones, either produced by the plant or sprayed on crops during cultivation, resulting in higher yield or improved traits. "We perhaps could engineer plants with altered sensitivity in different portions of the plant," says Wang. "For example, we could manipulate the signal pathway to increase the biomass accumulation in organs such as fruits that are important as agricultural products, an area highly relevant for food and biofuel production."

Another of the study's findings has potentially far-reaching consequences for human health. The newly identified brassinosteroid signaling pathway component shares evolutionarily conserved domains with the glycogen synthase kinase 3 (GSK3). "GSK3 is found in a wide range of organisms, including mammals," says Wang. "Our study identified a distinct mechanism for regulating GSK3 activity, different from what had been identified in earlier work. GSK3 is known to be critical in the development of health issues such as neural degeneration, cancer, and diabetes, so our finding could open up new avenues for research to understand and treat these diseases."

Source: Carnegie Institution

Explore further: New alfalfa variety resists ravenous local pest

add to favorites email to friend print save as pdf

Related Stories

Plant steroids offer new paradigm for how hormones work

Jul 24, 2008

Steroids bulk up plants just as they do human athletes, but the playbook of molecular signals that tell the genes to boost growth and development in plant cells is far more complicated than in human and animal cells. A new ...

Researchers Discover How Lithium Works

Jan 14, 2008

Despite more than 30 years of widespread use of lithium to control psychiatric disorders, such as bipolar disorder, scientists have been uncertain about how this drug actually works on a molecular level.

New gene that helps plants beat the heat

Oct 07, 2008

Michigan State University plant scientists have discovered another piece of the genetic puzzle that controls how plants respond to high temperatures. That may allow plant breeders to create new varieties of crops that flourish ...

Recommended for you

New alfalfa variety resists ravenous local pest

19 minutes ago

(Phys.org) —Cornell plant breeders have released a new alfalfa variety with some resistance against the alfalfa snout beetle, which has ravaged alfalfa fields in nine northern New York counties and across ...

New patenting guidelines are needed for biotechnology

18 hours ago

Biotechnology scientists must be aware of the broad patent landscape and push for new patent and licensing guidelines, according to a new paper from Rice University's Baker Institute for Public Policy.

Rainbow trout genome sequenced

20 hours ago

Using fish bred at Washington State University, an international team of researchers has mapped the genetic profile of the rainbow trout, a versatile salmonid whose relatively recent genetic history opens ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Husky
not rated yet Sep 08, 2009
It would appear to me that plants have these receptors
outside the nucleus as an added barrier protection against the many bacteria/viri plants in the wil might encounter. Multiple locks have to be picked before access is finally granted

More news stories

In the 'slime jungle' height matters

(Phys.org) —In communities of microbes, akin to 'slime jungles', cells evolve not just to grow faster than their rivals but also to push themselves to the surface of colonies where they gain the best access ...

New alfalfa variety resists ravenous local pest

(Phys.org) —Cornell plant breeders have released a new alfalfa variety with some resistance against the alfalfa snout beetle, which has ravaged alfalfa fields in nine northern New York counties and across ...

Former Iron Curtain still barrier for deer

The Iron Curtain was traced by an electrified barbed-wire fence that isolated the communist world from the West. It was an impenetrable Cold War barrier—and for some inhabitants of the Czech Republic it ...

Rainbow trout genome sequenced

Using fish bred at Washington State University, an international team of researchers has mapped the genetic profile of the rainbow trout, a versatile salmonid whose relatively recent genetic history opens ...

Robot scouts rooms people can't enter

(Phys.org) —Firefighters, police officers and military personnel are often required to enter rooms with little information about what dangers might lie behind the door. A group of engineering students at ...