Herbicide Resistance

Metabolic resistance of grass weeds against pre-emergence herbicides

The development of resistance to herbicides in weeds is a growing agronomic problem worldwide. Particularly so called non-target-site resistance (including enhances metabolism) has become a key threat due to multiple resistance across several modes of action. In various regions of the world resistance to the post-emergence ALS- and ACCase-inhibiting chemistries is a widespread and increasing problem in arable crops. In that regard, one of the key chemical options in temperate cereal-growing regions is the use of the pre-emergence herbicide flufenacet. As for any chemical weed control practice, the application of flufenacet is not sheltered from resistance development. The appearance of flufenacet-resistant ryegrass (Lolium spp.) populations in the USA and the artificial selection of flufenacet-resistant black-grass (Alopecurus myosuroides Huds.) populations over years in the United Kingdom point that out. So far, resistance to flufenacet in weeds has not been studied at the molecular level. Recent work demonstrated a significantly faster rate of degradation of flufenacet in both flufenacet resistant Lolium and Alopecurus populations. On this basis the goal of the PhD project is to characterize the pathway(s) involved in flufenacet detoxification. The degradation of flufenacet will be studied in an analytical and biochemical approach by identification of key metabolites and analysis of glutathione-S-transferases, which are known to be involved in flufenacet detoxification. Besides, a genomic approach using RNASeq will be used to study up and down regulation of genes involved in flufenacet resistance. In addition to the knowledge gained on flufenacet resistance mechanisms, the ultimate intention of this project is to offer molecular markers to permit development of early flufenacet resistance diagnostics. Fast, simple and reliable diagnostic tools will allow farmers to take the right strategy to efficiently perform weed control.

Funding Institution: Bayer Crop Science

Investigator: M.Sc. agr. Rebecka Dücker

Supervisors: Dr. Roland Beffa, Prof. Andreas von Tiedemann