Plant organ development breakthrough

Dec 03, 2012

Plants grow upward from a tip of undifferentiated tissue called the shoot apical meristem. As the tip extends, stem cells at the center of the meristem divide and increase in numbers. But the cells on the periphery differentiate to form plant organs, such as leaves and flowers. In between these two layers, a group of boundary cells go into a quiescent state and form a barrier that not only separates stem cells from differentiating cells, but eventually forms the borders that separate the plant's organs.

Because each plant's form and shape is determined by and organ boundary creation, elucidating the underlying mechanisms that govern these functions could help scientists design the architecture of to better capture light and ultimately produce more crop yield with less input. New research from two teams led by Carnegie's Zhiyong Wang and Kathryn Barton focuses on the role of the crucial brassinosteroid in the creation of plant-shoot architecture. Their work is published by during the week of December 3.

Like all organisms, plant growth and development is regulated by internally produced , including hormones like brassinosteroid, which is found throughout the plant kingdom. The brassinosteroid signaling pathway is involved in regulating more than 1,000 . that are deficient in brassinosteroid that are grown in the dark show features of plants grown in the light. They also have defects at many phases of the plant life cycle, including reduced seed germination, dwarfism, and sterility.

The new study lead by Wang and Barton uncovered yet another role of brassinosteroid: the formation of boundaries between organs. Plants made hypersensitive to brassinosteroid displayed fused organs.

The team included lead author's Carnegie's Joshua Gendron and Jiang-Shu Liu, as well as Min Fan, Mingyi Bai, and Stephan Wenkel, from Carnegie, and Patricia Springer from the University of California Riverside.

Their investigations showed that activation of the brassinosteroid pathway represses a group of genes called the cup-shaped cotyledon, or CUC family, which is responsible for organ boundary formation. Using sophisticated techniques the team demonstrated that the protein in the brassinosteroid pathway that is responsible for binding to DNA and, in this case, for inhibiting CUC genes, is present at high levels in the meristem's undifferentiated stem cells and developing organ primordia, but very low in the boundary cells, suggesting that different levels of brassinosteroid activity contribute to the opposite growth behavior of these three types of cells.

"This work links the plant steroids to growth and development, organ boundary development, providing a link between the physiology of the plant and its architectural design," Wang and Barton said.

Explore further: Vermicompost leachate improves tomato seedling growth

Related Stories

Steroids control gas exchange in plants

Feb 05, 2012

Plants leaves are sealed with a gas-tight wax layer to prevent water loss. Plants breathe through microscopic pores called stomata (Greek for mouths) on the surfaces of leaves. Over 40% of the carbon dioxide, CO2, in the ...

Unlocking the secrets of a plant's light sensitivity

Dec 13, 2010

(PhysOrg.com) -- Plants are very sensitive to light conditions because light is their source of energy and also a signal that activates the special photoreceptors that regulate growth, metabolism, and physiological ...

Lighting up the plant hormone 'command system'

Jul 22, 2012

Light is not only the source of a plant's energy, but also an environmental signal that instructs the growth behavior of plants. As a result, a plant's sensitivity to light is of great interest to scientists and their research ...

Nailing down a crucial plant signaling system

Jan 23, 2011

Plant biologists have discovered the last major element of the series of chemical signals that one class of plant hormones, called brassinosteroids, send from a protein on the surface of a plant cell to the cell's nucleus. ...

Mastermind steroid found in plants

Nov 15, 2010

Scientists have known for some time how important plant steroids called brassinosteroids are for regulating plant growth and development. But until now, they did not know how extensive their reach is. Now researchers, including ...

Recommended for you

Vermicompost leachate improves tomato seedling growth

Nov 21, 2014

Worldwide, drought conditions, extreme temperatures, and high soil saline content all have negative effects on tomato crops. These natural processes reduce soil nutrient content and lifespan, result in reduced plant growth ...

Plant immunity comes at a price

Nov 21, 2014

Plants are under permanent attack by a multitude of pathogens. To win the battle against fungi, bacteria, viruses and other pathogens, they have developed a complex and effective immune system. And just as ...

Evolution: The genetic connivances of digits and genitals

Nov 20, 2014

During the development of mammals, the growth and organization of digits are orchestrated by Hox genes, which are activated very early in precise regions of the embryo. These "architect genes" are themselves regulated by ...

Surrogate sushi: Japan biotech for bluefin tuna

Nov 20, 2014

Of all the overfished fish in the seas, luscious, fatty bluefin tuna are among the most threatened. Marine scientist Goro Yamazaki, who is known in this seaside community as "Young Mr. Fish," is working to ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.