Resistance evolution and weed shifts diagram. From New Phytologist.

EEB Professor Gina Baucom published a comprehensive, synthetic, single-authored Tansley Review in New Phytologist linking what’s been learned about herbicide resistance evolution in weedy plants with the ecological and evolutionary literature. The review takes the reader through research in weed science that addresses big “unknowns” in ecology and evolution. Baucom synthesizes the most recent literature and then highlights how herbicide resistant plants make excellent model organisms, specifically focusing on the new emerging field of eco-evolutionary “feedbacks.” The review was published Feb. 1, 2019.

“An unfortunate outcome of the reliance on herbicides is the evolution of herbicide resistance in weeds, where a once susceptible population is no longer controlled by a particular herbicide," Baucom wrote. "Researchers have studied herbicide resistance at the phenotypic, physiological, and genetic levels for roughly 60 years, often with the dual aims of diagnosing the scale of the resistance problem and the development of strategies that help delay its evolution and spread. While the study of herbicide resistant weeds is most often couched in the design of control programs, the wealth of knowledge gained on the resistance problem within the last 60 years – largely due to the efforts of weed biologists – has made herbicide resistant weeds models for understanding rapid adaptation to human-mediated regimes of selection, as well as model species in evolution and ecology more broadly. Strikingly, the basic discoveries stemming from the study of herbicide resistant plants have yet to be comprehensively synthesized in light of both current and emerging topics in ecology and evolution. 

“In this review, I synthesize recent research on the herbicide resistance problem in light of key questions and themes in evolution and ecology. I present emerging topics in evolution and ecology for which the phenomenon of herbicide resistance provides an excellent model system, and discuss the frameworks in which adaptation to herbicide has been and can be examined. More specifically, I first present discoveries made on herbicide resistant weeds in three areas broadly of interest to ecologists and evolutionary biologists – the genetic basis of adaptation, evolutionary constraints (fitness costs and life history trade-offs) and experimental evolution. Within each topic, I address the following: What have we learned about these broad areas from studies of herbicide resistant weeds? What questions within each topic would the phenomenon of herbicide resistance provide useful models? I then discuss contributions that herbicide resistance can add to the developing study of eco-evolutionary dynamics within a community context. My overall goal is to highlight important findings in the weed science literature that are relevant to current and emerging themes in plant adaptation and to stimulate the development of novel hypotheses of interest to both evolutionary biologists and weed scientists.”

Compiled by Gail Kuhnlein