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News Release 05-087

How Your Garden Grows

Stumped scientists figure out plant growth mechanism

Illustration of a plant and Auxin

Researchers have worked out the molecular steps auxins use to make plants grow.


May 25, 2005

This material is available primarily for archival purposes. Telephone numbers or other contact information may be out of date; please see current contact information at media contacts.

Just how does your garden grow? Plant scientists have long pondered the same question. For decades, the plant science community has known that auxins--a class of  plant growth hormones--control many aspects of plant growth and development, including cell enlargement, formation of buds, roots, flowers, and fruit, and autumnal loss of leaves. 

Exactly how auxins do all that has been a thorny uncertainty, but now the molecular steps in the growth process have been worked out.

In the May 26 issue of the journal Nature, Mark Estelle and colleagues at Indiana University, Bloomington, show that to do its job, auxin must first bind with a protein called TIR1. When it's time to grow, the auxin-TIR1 complex signals for the destruction of another protein that puts the brakes on plant growth. With the brakes off, growth genes become active, and the plant gets a boost.

"This long-sought after discovery represents an important advance in our understanding of fundamental biological processes," says Jane Silverthorne, program director at the National Science Foundation, which supported this research. "This advance in basic plant biology could also have important applications to developing improved crops."

Auxins and synthetic replicas are widely used commercially to produce more vigorous growth, promote root formation in plants not easily propagated by stem cuttings, control flowering and fruiting, retard fruit drop, and to produce seedless varieties of some fruit like tomatoes.  As auxins are found in all members of the plant kingdom, this breakthrough will not only allow researchers to better understand plant growth and development signals, it may also lead to improved cultivation practices. 

The research was also supported by the National Institutes of Health and the U.S. Department of Energy. 

For a complete story, see the news release at http://newsinfo.iu.edu/news/page/normal/2158.html.

-NSF-

Media Contacts
Richard (Randy) Vines, NSF, (703) 292-8070, email: rvines@nsf.gov

Program Contacts
Jane Silverthorne, NSF, (703) 292-8470, email: jsilvert@nsf.gov

Principal Investigators
Mark Estelle, Indiana University, Bloomington, (812) 856-1216, email: maestell@indiana.edu

The U.S. National Science Foundation propels the nation forward by advancing fundamental research in all fields of science and engineering. NSF supports research and people by providing facilities, instruments and funding to support their ingenuity and sustain the U.S. as a global leader in research and innovation. With a fiscal year 2023 budget of $9.5 billion, NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and institutions. Each year, NSF receives more than 40,000 competitive proposals and makes about 11,000 new awards. Those awards include support for cooperative research with industry, Arctic and Antarctic research and operations, and U.S. participation in international scientific efforts.

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