Fine-Tuning Immunity: Players and Regulators for Plant NLRs

Plants have evolved a sophisticated innate immune system to defend against pathogen infection, and intracellular nucleotide-binding, leucine-rich repeat (NLR or NB-LRR) immune receptors are one of the main components of this system. NLR activity is fine-tuned by intra- and intermolecular interactions. We survey what is known about the conservation and diversity of NLR-interacting proteins, and divide them into seven major categories. We discuss the molecular mechanisms by which NLR activities are regulated and how understanding this regulation has potential to facilitate the engineering of NLRs for crop improvement. NLR proteins are the major intracellular immune receptors in plants. Their transition between autoinhibited and activated states is fine-tuned by intra- and intermolecular interactions.NLR-interacting proteins play important roles in NLR-mediated immunity. Many NLR-interacting proteins have been identified; however, they have not been systematically classified.