patterntriggered

Patterntriggered is a term used to describe responses initiated by the recognition of conserved patterns, most commonly discussed in the context of pattern-triggered immunity (PTI) in plants. PTI represents the first layer of innate plant defense, activated when pattern recognition receptors detect pathogen-associated molecular patterns or damage-associated patterns.

In plants, pattern recognition receptors such as receptor-like kinases and receptor-like proteins bind to conserved microbial features like flagellin fragments or EF-Tu, as well as endogenous signals released from damaged tissue. Ligand binding activates receptor complexes with co-receptors, triggering signaling cascades that include calcium fluxes, MAP kinase activation, and the production of reactive oxygen species. These signals lead to transcriptional reprogramming and defense responses such as cell-wall fortification, antimicrobial compound synthesis, and stomatal closure to limit pathogen entry.

PTI is often contrasted with effector-triggered immunity (ETI). ETI arises when intracellular immune receptors detect specific pathogen effectors that suppress PTI, typically producing stronger or more rapid responses. PTI is generally broader and more durable across diverse pathogens, while ETI can be more specific and robust but susceptible to pathogen adaptation through effector evolution.

Beyond plants, the general phrase patterntriggered can describe any system where recognition of recurring patterns triggers a response. In biological contexts, however, it most commonly refers to pattern-triggered immunity and the associated receptor-mediated detection mechanisms.