NC State researchers identify genes key to hormone production...( Researchers at North Carolina State...)

Researchers at North Carolina State University have pinpointed a small group of genes responsible for telling plants when, where and how to produce a hormone that is key to their development. Their findings shed light on the ways in which hormone production in plants affects both a plants growth and its ability to adapt to changing environments.

Dr. Jose Alonso, assistant professor of genetics, and a team of geneticists and plant biologists from NC State, Germany and the Czech Republic conducted the research. Their findings are published in the April 4 edition of the journal Cell.

Plant growth and development are regulated by a small number of hormones, which plants combine in various ways so that they can adapt to and thrive in changing environmental conditions. Auxin and ethylene are two of the most important of these growth-regulating hormones.

Scientists had previously established that plants respond differently to ethylene depending upon the type of plant tissue it is applied to, the developmental stage of the plant, and the surrounding environmental conditions. They also knew that the presence of auxin, another key growth-regulator, often served as a trigger for a plant to produce more ethylene, but were unsure of the ways in which auxin was synthesized.

Auxin controls almost every process in a plant, Alonso says, and so its very important to understand how and why auxin is produced within the plant.

In order to find out more about how auxin production is triggered, the NC State team identified a mutant strain of Arabidopsis or mustard weed that had a root system insensitive to the growth inhibitory effect of ethylene.

When the team looked at the genome of this mutant strain of mustard weed, they discovered that its lack of response to ethylene was due to the changes in a gene that they named TAA1. This gene produces a protein that is necessary for auxin synthesis. In a normal plant, the
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