Impact of safeners on herbicide metabolism and metabolic profile in solo and mixture products

Maintaining the effective control of weeds in arable crop production is one of the principal problems faced by modern agriculture. Herbicide resistance in weeds has reduced the selectivity of many herbicides, which when coupled with the loss of many herbicides from the market[1], demonstrates a clear requirement for improving weed control methods.
Safeners are agrochemicals that increase herbicide tolerance in large grained cereals, reducing crop damage and enhancing selective weed control. While the mode of action of safening is not fully understood, it is known to be associated with the increased expression of xenobiotic detoxifying enzymes, collectively termed the xenome[2], that results in the accelerated metabolism and sequestration of herbicides. While safeners are intended for use with specific partner herbicides, their ability to cause large changes in xenome expression has the potential to modify the metabolism of other classes of pesticides which may be present in mixture products. In addition, the changes to herbicide metabolism caused by safeners are still elusive, and may include the production of aberrant metabolites, modified levels of conventional metabolites, and alterations in final residue composition. This, therefore, presents a safety risk to consumers of cereal food products, which must be addressed.
In this project, the ability of safeners to alter the rate and/or route of detoxification of a range of systemic pesticides will be determined in key cereal crops, with a focus on herbicide mixtures. By developing a detailed understanding of the generic effects of safeners on xenome components and metabolic profiles, a predictive framework for anticipating changes in the metabolism of a range of pesticide chemistries will be developed, through a combination of empirical measurement and modelling. Training will focus on developing a detailed understanding of pesticide metabolism in planta, relevant to the crop protection industry, and also on gaining experience in studying the molecular biology, biochemistry and regulation of the xenomes of agronomically important crops. This project should offer valuable insight into the effects that commercial safeners have on metabolic profiles and residue profiles in cereal crops, thus creating a stronger scientific basis to support the crop protection field, and to address the issues with food security and sustainability.

1. Heap, I., Global perspective of herbicide-resistant weeds. Pest management science, 2014. 70(9): p. 1306-1315.
2. Edwards, R., et al., New perspectives on the metabolism and detoxification of synthetic compounds in plants, in Organic xenobiotics and plants. 2011, Springer. p. 125-148.