Growing drought-tolerant crops inching forward

August 25, 2010

A collaborative team of scientists led by researchers at The Medical College of Wisconsin, in Milwaukee, has used the tools of structural biology to understand how a synthetic chemical mimics abscisic acid (ABA), a key stress hormone that helps plants cope with adverse environmental conditions such as drought. The results are published online in Nature Structural & Molecular Biology in advance of print publication later.

For years scientists have searched for practical ways to use ABA signaling to improve drought tolerance in agriculture. Unfortunately, the synthetic form of ABA used commercially is light sensitive and expensive. The new study builds on the earlier discovery by scientists at University of California, Riverside of pyrabactin, a synthetic chemical that mimics ABA. However, unlike ABA, pyrabactin activates only a few of the 14 ABA receptors in the plant needed for effective drought tolerance.

"By better understanding how pyrabactin works, we can develop new chemicals to enable to resist drought. These same chemicals that signal the response to may also contribute to increasing crop yields," says Francis Peterson, Ph.D., lead author and assistant professor of biochemistry at the Medical College.

An ABA receptor is a protein that functions as a molecular switch inside the cell. When an ABA molecule inserts into a cavity within the receptor, it sends a signal by changing the protein structure in a way that resembles the closing of a gate. To identify the specific atoms required for gate closure by ABA or pyrabactin, Dr. Peterson used X-ray diffraction to solve the three-dimensional structures of multiple receptor proteins. From the changes in position of only a few atoms, the research team discovered why pyrabactin can close the gate on some receptors but not others.

"These insights suggest new strategies for modifying pyrabactin and related compounds so that they can mimic the signaling process of the naturally occurring ABA. This work has paved the way for manufacturing new molecules that activate or turn on receptors" said Sean Cutler, Ph.D., associate professor of plant cell biology at UC Riverside.

"The current research is an important step on the way to what is likely to be the next big result: an ABA-mimicking chemical that can be applied to corn, soy bean and other crops," explained Dr. Peterson.

In addition to Drs. Peterson and Cutler, research collaborators included Brian Volkman, Ph.D., Davin R. Jensen and Joshua J. Weiner of the Medical College of Wisconsin; as well as Sethe Burgie, Craig A. Bingman and George N. Phillips, Jr. of the University of Wisconsin-Madison; and Sang-Youl Park and Chia-An Chang of UC Riverside.

An NIH grant for structural genomics supported the work in the Volkman lab at the Medical College, and a grant from the National Science Foundation supported Cutler's contribution to the study.

"The project described was supported by the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health."

Explore further: Researchers identify a process that regulates seed germination

More information: Cutler is a coauthor also on a companion paper, titled "Identification and Mechanism of ABA Receptor Antagonism," that appeared online in Nature Structural & Molecular Biology.

Related Stories

Synthetic chemical offers solution for crops facing drought

April 30, 2009

Crops and other plants are constantly confronted with adverse environmental conditions, lowering yield and costing farmers billions of dollars annually. Plants use specialized signals, called stress hormones, to sense difficult ...

Drought resistance explained

November 9, 2009

Much as adrenaline coursing through our veins drives our body's reactions to stress, the plant hormone abscisic acid (ABA) is behind plants' responses to stressful situations such as drought, but how it does so has been a ...

Recommended for you

Researchers design first artificial ribosome

July 29, 2015

Researchers at the University of Illinois at Chicago and Northwestern University have engineered a tethered ribosome that works nearly as well as the authentic cellular component, or organelle, that produces all the proteins ...

Studies reveal details of error correction in cell division

July 29, 2015

Cell biologists led by Thomas Maresca at the University of Massachusetts Amherst, with collaborators elsewhere, report an advance in understanding the workings of an error correction mechanism that helps cells detect and ...

Researchers discover new type of mycovirus

July 29, 2015

Researchers, led by Dr Robert Coutts, Leverhulme Research Fellow from the School of Life and Medical Sciences at the University of Hertfordshire, and Dr Ioly Kotta-Loizou, Research Associate at Imperial College, have discovered ...

Stressed out plants send animal-like signals

July 29, 2015

University of Adelaide research has shown for the first time that, despite not having a nervous system, plants use signals normally associated with animals when they encounter stress.

0 comments

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.