0817MolecularPathways1PIXsr.cfm Malatya Haber Using a universal pathway to control weeds
Home News Livestock Crops Markets Hay, Range & Pasture Home & Family Classifieds Resources This Week's Journal
Commerical Hay Equipment For The Farm
Agro-Culture Liquid Fertilizer

Farm Survey

Journal Getaways

Reader Comment:
by ohio bo

"An excellent essay on fairs that brought back many memories for me. In my part"....Read the story...
Join other discussions.

Using a universal pathway to control weeds

Plant physiologist Franck Dayan observes wild-type and herbicide-resistant biotypes of pigweed (Palmer Amaranth) as Mississippi State University graduate student Daniela Ribeiro collects plant samples for DNA analysis. (Photo by Stephen Ausmus.)

A U.S. Department of Agriculture scientist in Oxford, Miss., is working toward developing new herbicides by focusing on a molecular pathway that not only controls weeds, but could have helped shape our nation's history.

Franck Dayan, a plant physiologist with the USDA's Agricultural Research Service Natural Products Utilization Research Unit in Oxford, is an expert on a class of weed killers known as "PPO herbicides," which choke off the weed's ability to make chlorophyll. Many weeds are developing resistance to glyphosate, the world's most widely used herbicide, and alternatives are needed.

ARS is USDA's principal intramural scientific research agency, and the research supports the USDA priority of promoting international food security.

Much of Dayan's work focuses on ring-shaped pigment molecules known as porphyrins (pronounced POR-fer-ins) that "bind" or react with different metals and perform vital functions in both plants and animals. A key step in porphyrin synthesis is performed by an enzyme (protoporphyrinogen oxidase or PPO), and disrupting the PPO enzyme can cause problems in plants and animals.

In humans, disruption is associated with a congenital disease known as porphyria, with symptoms that may include sensitivity to light, seizures, and other neuropsychiatric problems. In plants, PPO herbicides work by disrupting the enzyme's production of porphyrins and inhibiting photosynthesis. PPO herbicides have been around for decades and are specifically designed so they will only disrupt PPO enzyme activity in plants and not in humans.

Dayan recently published a report on the role PPO enzymes play in triggering resistance to PPO herbicides in waterhemp (Amaranthus tuberculatus), a common weed. He and his colleagues compared the molecular structure of PPO enzymes in resistant and susceptible water hemp. The results confirmed that deletion of a single amino acid, known as glycine 210, caused structural changes in the enzyme binding site that allows waterhemp to develop herbicide resistance. The work, published in the journal Biochimica et Biophysica Acta, built on previous research showing waterhemp's resistance capabilities. Understanding the resistance mechanisms should lead to better herbicides.

In another report, Dayan described the diverse roles played by porphyrins and PPO enzymes as essential components of life on earth. The article in American Scientist notes that life couldn't exist without them, and recounts how scholars have argued that a case of porphyria in King George III may have contributed to our nation's struggle for independence.

Read more about the research in the August 2012 issue of Agricultural Research magazine at www.ars.usda.gov/is/AR/archive/aug12/enzyme0812.htm.

Date: 9-24-2012

Web hpj.com

Copyright 1995-2014.  High Plains Publishers, Inc.  All rights reserved.  Any republishing of these pages, including electronic reproduction of the editorial archives or classified advertising, is strictly prohibited. If you have questions or comments you can reach us at
High Plains Journal 1500 E. Wyatt Earp Blvd., P.O. Box 760, Dodge City, KS 67801 or call 1-800-452-7171. Email: webmaster@hpj.com


Archives Search

NCBA Convention

United Sorghum Checkoff Program

Inside Futures

Editorial Archives

Browse Archives