Disease lesion mimics of maize: A model for cell death in plants

Abstract A class of maize mutants, collectively known as disease lesion mimics, display discrete disease‐like symptoms in the absence of pathogens. It is intriguing that a majority of these lesion mimics behave as dominant gain‐of‐function mutations. The production of lesions is strongly influenced by light, temperature, developmental state and genetic background. Presently, the biological significance of this lesion mimicry is not clear, although suggestions have been made that they may represent defects in the plants' recognition of, or response to, pathogens. One feature that is common to all lesion mimics is their association with cell death. In plants, as in animals, a number of developmental and pathological processes exist where controlled cell death, whether programmed or triggered in response to physiological or environmental stimuli, constitutes the normal aspect of life. Might disease lesion mimic mutations represent variants where regulation of desirable cell death has gone awry? In this paper we argue that this might be the case, and further conjecture that these mutants offer a unique opportunity for studying the genetic and cellular mechanisms of cell death in plants.