Hosted by: Joanna Fowler

Identified as a form of plant immunity nearly 100 years ago, systemic acquired resistance (SAR) is a highly desirable form of resistance that protects against a broad-spectrum of pathogens. SAR involves the generation of a mobile signal at the site ofprimary infection, which moves to, and arms distal portions of a plant against subsequent secondary infections. Because of its unique mechanistic properties and its exciting potential applications in developing sustainable crop protection strategies, SAR has been one of the most intensely researched areas of plant biology. The last decade has witnessed considerable progress and a number of signals contributing to SAR have been isolated and characterized. Among the signals contributing to SAR are salicylic acid (SA) and several components that feed into SA pathway including the methylated derivative of SA (MeSA), the nine carbon dicarboxylic acid azelaic acid, the phosphorylated sugar glycerol-3-phosphate (G3P), and two lipid transfer proteins (LTPs) DIR1 (Defective in Induced Resistance) and AZI1 (AA insensitive). The diverse chemical natures of the SAR inducing molecules have led to the growing belief that SAR might involve the interplay of multiple diverse and independent signals. More recent evidence suggests that coordinated signaling from diverse signaling components facilitates systemic immunity in plants. Relationship among recently identified mobile inducers of SAR will be discussed.