PRRs and NLRs sans frontières: advances and challenges in transfer of immune receptors between plant species

Plants employ cell-surface and intracellular immune receptors to perceive pathogens and activate defense responses. Recent advances in mechanistic understanding of how cell-surface and intracellular immune receptors convert recognition of molecular patterns or effectors into defense activation, combined with the knowledge of receptor repertoire variation both within and between species, allow transfer of immune receptors between species to increase the spectrum of recognition specificities. Here, we summarize recent progress in the functional transfer of immune receptors within and between plant families. We also discuss challenges that limit the transferability of intracellular immune receptors, including the requirement of additional host factors or downstream components and their incompatibility between donor and recipient species. Finally, we provide an overview of future perspectives for bioengineering disease-resistant crops through immune receptor transfer.