Résumé
Plant–pathogen co‐evolutionary selection processes are continuous, complex and occur across many spatial and temporal scales. Comprehensive studies of the flax–flax rust pathosystem have led to the postulation of the gene‐for‐gene model, a genetic paradigm describing recognition events between host disease resistance proteins and pathogen effector proteins. The identification of directly interacting fungal effector proteins and plant disease resistance proteins in this pathosystem has facilitated the study of both the physical nature of these interactions and the evolutionary forces that have resulted in a molecular arms race between these organisms. The flax–flax rust pathosystem has also been detailed on the scale of interacting populations, and the integration of molecular‐ and population‐scale datasets represents a unique opportunity to further our understanding of many poorly understood facets of host–pathogen dynamics. In this article, we discuss recent developments and insights in the flax–flax rust pathosystem and their implications for both long‐term co‐evolutionary dynamics in natural settings, as well as short‐term co‐evolutionary dynamics in agro‐ecosystems.