6533b7ddfe1ef96bd12744ba

RESEARCH PRODUCT

To resistance mechanisms and beyond: an evolutionary approach of herbicide resistance

subject

description

The diversity of herbicide resistance mechanisms observed today in weed populations is the result of a very rapid evolution in response to the selection pressure exerted by herbicide applications. Herbicide resistance is a dynamic process: weed populations are undoubtedly still continuing to evolve, so that the long-term outcome of herbicide selection is currently unpredictable. The vast majority of the studies addressing herbicide resistance published to date are focussed on the identification of mechanisms endowing resistance, with the applied aim to develop resistance diagnosis methods. Understanding resistance evolution is key to set up proactive weed management strategies that should integrate both herbicides and non-chemical tools, and elucidating the genetic bases of resistances is a prerequisite to understand the evolution of resistance. However, understanding the evolution of resistance requires to go beyond the mere identification of resistance genes, and to understand the processes driving herbicide resistance evolution in weed populations. This can only be achieved by addressing the evolutionary dynamics of resistance, and by implementing integrative modelling efforts with an aim to predict resistance evolution. This implies studying the probability of appearance or the initial frequency of resistance genes, the genetic architecture of resistance, its spread within and among weed populations as well as the associated pleiotropic effects (e.g. fitness cost) of resistance mechanisms. The evolutionary dynamics of herbicide resistance has rarely been addressed considering all these aspects. The interest of integrative evolutionary approaches of herbicide resistance will be illustrated using as an example the resistance case most intensely studied from the point of view of resistance evolution: resistance to ACCase inhibitors in grass weeds.