Evolution of resistance to phytoene desaturase-inhibiting herbicides

AGRO 109

Franck E. Dayan, fdayan@olemiss.edu, Natural Products Utilization Research Unit, USDA-Agricultural Research Service, P.O. Box 8048, University, MS 38677, Brian Scheffler, USDA, ARS, CGRU, P.O. Box 38, Stoneville, MS 38776, Renee S. Arias, Oregon State University, Richardson Hall 321, Corvallis, OR 97331-5752, Albrecht Michel, Syngenta Crop Protection AG, Herbicide Profiling Biology, WST-149.E.62, Stein, CH-4332, Switzerland, and Michael D Netherland, University of Florida Center for Aquatic and Invasive Plants, US Army Engineer Research and Development Center, Gainesville, FL 32653.
Compounds targeting the carotenoid biosynthetic pathway are particularly attractive because they are potent herbicides with high margins of safety to animals. Phytoene desaturase (PDS) is the most common herbicide target site in this pathway. Several herbicide classes (e.g., pyridazinones, aryloxypicolinamide, and phenoxybutanamide) inhibit PDS by competing for the binding site of plastoquinone, an essential co-factor. PDS inhibitors represent a relatively small portion of the herbicide market partly due to a lack of sufficient species selectivity. Several biotypes of the submersed aquatic weed hydrilla have become resistant to fluridone, the only herbicide approved by the USEPA for systemic treatment of large water bodies. The resistant biotypes are expected to spread and are likely to pose significant environmental challenges in the future. However, the genes encoding herbicide-resistant PDS can also be used in transgenic crops to increase crop safety margins, thus potentially expanding the marketability of these herbicides.
 

Weed Resistance to Herbicides
1:30 PM-4:15 PM, Tuesday, 12 September 2006 San Francisco Marriott -- Salon 3, Oral

Division of Agrochemicals

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006