Innate immunity in plants and animals: striking similarities and obvious differences

Innate immunity constitutes the first line of defense against attempted microbial invasion, and it is a well-described phenomenon in vertebrates and insects. Recent pioneering work has revealed striking similarities between the molecular organization of animal and plant systems for nonself recognition and anti-microbial defense. Like animals, plants have acquired the ability to recognize invariant pathogen-associated molecular patterns (PAMPs) that are characteristic of microbial organisms but which are not found in potential host plants. Such structures, also termed general elicitors of plant defense, are often indispensable for the microbial lifestyle and, upon receptor-mediated perception, inevitably betray…