Molecular basis for resistance to fenoxaprop-p-ethyl in American sloughgrass (Beckmannia syzigachne Steud.)

American sloughgrass is a widespread and competitive annual grass weed of wheat in Yangtze River delta of China. Whole-plant dose–response experiments were conducted with fenoxaprop-p-ethyl to confirm and characterize resistant and susceptible American sloughgrass populations. The resistant American sloughgrass population Dylj was 21.73-fold resistant to fenoxaprop-p-ethyl relative to the susceptible population Dyyh. PCR analysis was conducted to elucidate the basis of resistance to the herbicide. Molecular analysis of resistance confirmed that the Ile1781 to Leu mutation in the resistant population conferred resistance to fenoxaprop-p-ethyl. This is the first report of a target site mutation that corresponded to resistance to fenoxaprop-p-ethyl in American sloughgrass.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The Dylj population was 21.73-fold resistant to fenoxaprop. ► An Ile1781 to Leu mutation was found in CT domain of ACCase of resistant population. ► The mutation was conferred by a single-point mutation. ► The fenoxaprop resistance of American sloughgrass is based on an altered target.