Innovations to control troublesome weeds
Term: 3 years, beginning 2024
Status: Ongoing
Researcher(s): Steve Robinson, AAFC
SaskCanola Investment: $82,875
Total Project Cost:
Funding Partners: WGRF, MCA, SPG, SWDC
Objective
1. Generate kochia gene sequences from prairie isolates.
2. Generate dsRNA to selected genes incorporating necessary safety design protocols.
3. Generate new RNAi-based herbicides to control troublesome kochia weeds.
4. Develop application strategies that are practical for the field.
Project Description
Effective weed management is critical to maximizing harvest efficiency and yield potential for producers and this is achieved by the application of efficacious herbicides. These herbicides have become a victim of their own success, as the selection pressure they apply to control weed populations inevitably leads to the evolution of herbicide resistance within those populations. This process is exacerbated by repeated application of the same herbicide group to the same field. In addition to the evolution of resistance, there are growing concerns that the number of tools available to producers for effective weed management is dwindling, due to restrictions applied by regulatory bodies to meet safety and marketing constraints. Regulatory constraints are anticipated to tighten as governments respond to environmental concerns and increased public demand for sustainable production practices. There is clearly a need to develop alternative herbicides to support the agriculture sector.
Advances in DNA sequencing technology have allowed the application of genomics to be applied beyond model organisms and major crop plant species to crop pathogens, insects and weed species. This is exemplified by the development of a draft genome sequence available for the troublesome weed kochia (Bassia scoparia). This foundational information can be built upon to develop targeted strategies to control highly concerning invasive species.
The potential of exploiting RNA interference (RNAi) to induce targeted gene silencing has already been established. This technology has matured to the extent where RNAi is being used to control fungal pathogens and insect herbivory for our major crops. Technologies have been developed to induce RNAi through the application of double-stranded RNA (dsRNA) molecules, avoiding regulatory concerns from the use of genetically modified organisms maintaining access to valuable export markets.
The information gap that this project will address is to determine whether RNAi-based gene silencing can be induced in plants by delivering exogenous dsRNA molecules to target essential genes compromising plant growth or resulting in plant death. This project will evaluate the potential of targeted gene silencing using dsRNA for weed control, specifically targeting the problematic weed kochia, an annual weed that is endemic throughout North America. Among the weed species Canadian producers frequently need to control, kochia is of particular concern as it can rapidly become a problem with its invasiveness promoted by abundant seed production, efficient seed dispersal, high levels of abiotic stress tolerance and increasing levels of resistance to herbicides. This project builds on the success of RNAi-based strategies to control fungal pathogens and the timing is optimal to develop these strategies as a control for troublesome weeds with innovative companies now able to manufacture RNA molecules at scale and at costs necessary to meet the needs of agricultural producers.
Although the project will evaluate the potential of gene silencing to control kochia, if successful, this strategy can be applied to other troublesome weeds by simply changing the dsRNA sequences. There is a need to investigate the potential of new technologies that might be exploited toward increasing weed management options available to producers that are free from the use of chemical herbicides.