NLR diversity, helpers and integrated domains: making sense of the NLR IDentity

- Plant NLR immune receptors are rapidly diversifying modular proteins.
- There is a vast diversity in NLR copy number and allelic variation across species.
- NLRs are sensors of pathogen effectors or plant proteins, including other NLRs.
- NLRs and their interactors can be linked together on a genetic and protein level.

Plant innate immunity relies on genetically predetermined repertoires of immune receptors to detect pathogens and trigger an effective immune response. A large proportion of these receptors are from the Nucletoide Binding Leucine Rich Repeat (NLR) gene family. As plants live longer than most pathogens, maintaining diversity of NLRs and deploying efficient 'pathogen traps' is necessary to withstand the evolutionary battle. In this review, we summarize the sources of diversity in NLR plant immune receptors giving an overview of genomic, regulatory as well as functional studies, including the latest concepts of NLR helpers and NLRs with integrated domains.