Fig. 1From: Diversification of defensins and NLRs in Arabidopsis species by different evolutionary mechanismsOutline of the major phases of plant immune responses. Pathogen detection can take place through direct interactions between pathogen-associated molecular patterns (PAMPs) and transmembrane receptor-like kinases RLKs or pathogen effectors and intracellular NLRs (CNLs and TNLs). After detection CNLs and TNLs trigger different signaling pathways: the pathway activated by PAMP binding involves a cascade of mitogen-activated protein kinases (MAPKs) and activation of WRKY transcription factors. A second pathway is activated by cytoplasmic proteins EDS1, PAD4, NDR1 and salicylic acid (SA). Both pattern triggered immunity (PTI) and effector triggered immunity (ETI) pathways result in a response where pathogenesis-related (PR) genes are upregulated. These include genes encoding defensins, chitinases, β-1,3-glucanases, protease inhibitors and lipid transfer proteins. As an example, transportation and secretion of defensins, which like other PR proteins have pathogen-killing activity, is indicatedBack to article page