Crops and weeds running to stand still in the red queen’s climate change race

The Red Queen Hypothesis formulated by evolutionary biologist Leigh Van Valen describes how coevolving species are engaged in a continuous arms race. The hypothesis was inspired by Lewis Caroll’s novel “Through the Looking Glass” where the Red Queen says to Alice “Now, here, you see, it takes all the running you can do, to keep in the same place.” In this review we examine how climate change has heightened the arms race between crops and weeds and reflect on how these closely related entities are engaged in a race to adapt to climate change, which represents a serious threat to agricultural productivity. Weeds are adapting to climate change relatively rapidly, whereas crop evolution is restricted by traditional breeding programs to emphasize crop yields and genetic uniformity. Crops and weeds share much evolutionary history, with crops having been created by domestication of plant species which are often now classified as weeds. For example, in the case of rice, domestication resulted in a lack of infructescence shattering and seed dormancy. However, weedy rice which possesses both ancestral traits is now a serious pest of domestic rice, and continues to evolve, including developing traits for climate change resilience. We highlight the need to utilize knowledge of weed evolution and genomics in crop breeding, even to the point of incorporating genes from weeds as a possibility. Modern gene editing techniques must be utilized extensively to speed up crop improvement and help crops keep up to weeds in the Red Queen’s climate change race.

Weed Evolution; Crop Breeding; CRISPR; Weed Genomics; Hybridization; Coevolution; GMOs; Crop Wild Relatives