Exploring the Physiological Basis of Costs of Herbicide Resistance in Arabidopsis thaliana.

For some resistance traits identified in crop and weed species, plant physiologists have detailed knowledge of the mechanism of gene action that distinguishes the physiology of resistant and susceptible genotypes. Such information could be useful to those evolutionary biologists interested in coupling the genetics and physiology of resistance mutations with data on the relative fitness of resistant and susceptible genotypes. In previous work, we have shown that the lifetime seed production of chlorsulfuron-resistant Arabidopsis thaliana was substantially lower than that of susceptible plants, and here we explore potential physiological reasons for the fitness reduction. In addition, we highlight several methodological issues that are essential when using transgenic technology to explore fitness trade-offs.