Studying herbicide modes of action and detoxification using Marchantia polymorpha

Crop yields worldwide are threatened by weeds which compete with crops for resources such as light, water, and soil nutrients. Using herbicides to kill weeds is the most effective manner of preventing weeds from causing devastating crop losses. Currently, farmers rely on a small number of herbicides to keep weeds in check, but overreliance on these herbicides has led to the evolution of herbicide resistant weeds which can survive herbicide treatments. New herbicides which kill weeds in different ways are needed to eradicate these resistant weeds and prevent them from spreading. One potential source of new herbicides are products produced naturally by organisms which kill plants for their own benefit. For example, thaxtomin A is a natural product which kills plants and is produced by bacteria which feed on potato plants. We do not know how thaxtomin A works, but we know it can kill plants and therefore could be used as a basis to design new herbicides. This project aims to determine how thaxtomin A kills plants using the land plant Marchantia polymorpha. Knowledge of how thaxtomin A works can be used to design new herbicides which work in the same way but which are cheaper to produce and safer to use in the environment than thaxtomin A. However, finding new herbicides will not completely solve the problem of herbicide resistant weeds: some weeds are resistant even to new herbicides because they can break down different types of herbicides to harmless products by a process known as detoxification. This project also aims to understand the genetic basis of thaxtomin A detoxification in M. polymorpha in order to be able to detect weeds which can detoxify herbicides in the field and to better understand how to eradicate them.

The proposed research addresses the BBSRC priority of sustainably enhancing agricultural production as well as the cross-council priority of global food security.