Flufenacet resistance in ryegrasses

Herbicide resistance to inhibitors of very-long-chain fatty acid (VLCFA, HRAC group 15) biosynthesis e.g. flufenacet is increasing in different cropping systems. Several weedy ryegrass species can evolve resistance to this herbicide group including Lolium rigidum and Lolium multiflorum. We have sampled each six seedlings of three susceptible and three flufenacet resistant Lolium spp. populations. One suscpetible and one resistant L. multiflorum population were additionally harvested one hour after herbicide treatment. We experimentally confirmed that a tau class GST detoxifies flufenacet at a high rate. Therefore, the observed phenotye is caused by metabolic resistance.