Plant immune receptor pathways as a united front against pathogens

Abstract

Plants evolved the innate immune system to activate disease resistance mechanisms and fend off microbial invaders. This system comprises two major signaling cascades initiated by two classes of immune receptors, the cell-surface immune receptors, also named pattern recognition receptors (PRRs), and intracellular immune receptors, also named nucleotide-binding domain leucine-rich repeat receptors (NLRs). PRRs and NLRs possess distinct biochemical activities and are activated via largely independent mechanisms. And yet, the downstream immune responses and outputs are strikingly similar, suggesting connectivity and convergence between the two pathways. Indeed, recent studies significantly advanced our understanding of the intimate relationship of interdependence and mutual potentiation between the two cascades. A united view of plant innate immunity is emerging.