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Posted 12.07.06


Researchers Identify Peptide Protectors of Plant Roots

COLUMBIA, MO - Plants at the University of Missouri-Columbia are being equipped with a new form of defense to fight infection. Researchers at MU have identified peptides that when produced in plants protect the roots of agricultural crops such as tomatoes, melons, peppers and squash against invasion by Phytophthora capsici, a dangerous pathogenic microorganism.

Frank Schmidt & James English..The breakthrough was made by professors Frank Schmidt and James English of the College of Agriculture, Food and Natural Resources and the School of Medicine. The findings are expected to help plant scientists better understand how to combat a variety of diseases, including Asian Soybean rust, a soybean disease that was introduced to the United States around 2004 as a result of winds from Hurricane Ivan.

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Proceedings of the National Academy of Sciences

"There's a constant search for new types of resistance for plants," said English, a professor of plant pathology. "This research is about developing and applying new technologies that will help plants defend themselves. Our hope is that the deployment of these peptides will protect against the invasion and killing of plants by keeping pathogens from invading their roots."

During the study, Schmidt and English relied on a library of one billion laboratory-created peptides. They worked first with tomato pathogens and then tomatoes. They mixed the peptides with Phytohpthora capsici and monitored which peptides stuck to the pathogen most effectively - signifying a strong chemical interaction. Afterwards, they tested the effects of the most interactive peptides on the growth and development of the pathogen. English said that 50 percent of the peptides that stuck strongly produced an inhibitory reaction that could be useful in defending tomatoes against the pathogenic microorganism.

"Having these peptides in hand was only the first step in practical application for plant defense," English said. "What was also needed was a means to deliver the peptide to provide protection against the pathogen. To do that, we modified a plant protein to display the peptide. When this combination was expressed in the plant, it provided protection from infection."

Both researchers said the positive findings could accelerate the development of more environmentally safe solutions for fighting infections that could potentially damage large areas of plants, trees or consumer crops.

"What this shows is that we can do test-tube evolution quickly and use the results to engineer resistances for plants," Schmidt said. "By engineering these resistances, we don't have to fumigate the soil, which has horrible environmental consequences."

Their study has been published online in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).



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