Activation of plant pattern-recognition receptors by bacteria.

The first active layer of plant innate immunity relies on the recognition by surface receptors of molecules indicative of non-self or modified-self. The activation of pattern-recognition receptors (PRRs) by pathogen-associated molecular patterns (PAMPs) is in essence sufficient to stop pathogen invasion through transcriptional reprogramming and production of anti-microbials. The few PRR/PAMP pairs that are characterised provide useful models to study the specificity of ligand-binding and likely activation mechanisms. Both classical and new approaches are still required to identify new bacterial PAMPs. Current genetic screens, functional genomics and biochemical analyses have identified the regulation mechanisms of PRR transcription and biogenesis, provided insights into the composition of PRR complexes at the plasma membrane and highlighted the roles of long-known signalling components in PAMP-triggered immunity (PTI).