The dicotyledonous species Erodium moschatum (L) L'Her. ex Aiton is sensitive to haloxyfop herbicide due to herbicide-sensitive acetyl-coenzyme A carboxylase

Most plants are resistant to herbicides which inhibit acetyl-coenzyme A car boxylase (ACCase) because they have both eukaryotic ACCase and herbicide-in sensitive, prokaryotic ACCase. Members of the Gramineae are killed because they have only herbicide-sensitive, eukaryotic ACCase. Here we report that a dicot, Erodium moschatum, is sensitive to the ACCase-inhibiting herbicide haloxyfop because it has herbicide-sensitive ACCase. Erodium moschatum was controlled by haloxyfop application at rates which controlled the gramineo us species Digitaria cilliaris and a susceptible Lolium rigidum biotype but did not control the dicot Nicotiana tabacum or a haloxyfop-resistant L. ri gidium biotype WLR96. Similarly, the haloxyfop acid concentration required to inhibit activity by 50% in E. moschatum ACCase assays (1.0 mu M) was sim ilar to that required for D, cilliaris (2.3 mu M) and susceptible L. rigidu m (0.4 mu M) but much less than that for the resistant L. rigidum biotype W LR96 (353 mu M) or the dicots N. tabacum (182 mu M) and Pisum sativum (150 mu M) Leaf protein extracts from N, tabacum and P. sativum contained both e ukaryotic ACCase and prokaryotic subunits of ACCase, but E. moschatum, D. c iliaris and both L. rigidum biotypes exhibited only the eukaryotic ACCase. Thus, the dicot E. moschatum is sensitive to haloxyfop because it lacks the herbicide-insensitive prokaryotic ACCase, a protein that has been consider ed ubiquitous in dicot species.