Virus-Mediated Transient Expression Techniques Enable Gene Function Studies in Black-Grass

Weeds are arguably among the most economically important groups of plant species. They have major agronomic and environmental impacts and affect food security. For winter-cereal farmers in western Europe, black-grass (Alopecurus myosuroides) is the most problematic weed, as it survives chemical control methods (Hicks et al., 2018; Varah et al., 2020) and reproduction occurs within a standard cropping cycle (Moss, 1983; Colbach et al., 2006). Importantly, black-grass also directly reduces yields (Varah et al., 2020). New disruptive technologies mitigating herbicide resistance evolution and enabling better control are therefore urgently required. This could be achieved by gaining a better understanding of black-grass biology and identifying genes underpinning its success as an agricultural weed. However, functional studies have been impeded by the lack of tools for genetic transformation and/or functional genomics in this species. Here, we demonstrate the transient expression tools virus-induced gene silencing (VIGS) and virus-mediated protein overexpression (VOX) developed for crop monocots can be used in black-grass.