PTI-ETI crosstalk: an integrative view of plant immunity

Plants resist attacks by pathogens via innate immune responses, which are initiated by cell surface-localized pattern-recognition receptors (PRRs) and intracellular nucleotide-binding domain leucine-rich repeat containing receptors (NLRs) leading to pattern-triggered immunity (PTI) and effector-triggered immunity (ETI), respectively. Although the two classes of immune receptors involve different activation mechanisms and appear to require different early signalling components, PTI and ETI eventually converge into many similar downstream responses, albeit with distinct amplitudes and dynamics. Increasing evidence suggests the existence of intricate interactions between PRR-mediated and NLR-mediated signalling cascades as well as common signalling components shared by both. Future investigation of the mechanisms underlying signal collaboration between PRR-initiated and NLR-initiated immunity will enable a more complete understanding of the plant immune system. This review discusses recent advances in our understanding of the relationship between the two layers of plant innate immunity.

Automated summary

Plants have innate immune responses to resist pathogen attacks, involving pattern-recognition receptors (PRRs) and nucleotide-binding domain leucine-rich repeat containing receptors (NLRs) that lead to pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Despite different activation mechanisms, PTI and ETI converge into similar downstream responses, with evidence of interactions and shared components between PRR-mediated and NLR-mediated signaling cascades. Future research on signal collaboration between PRR-initiated and NLR-initiated immunity will provide a more comprehensive understanding of the plant immune system.