Using DIR1 to investigate long-distance signal movement during Systemic Acquired Resistance

During Systemic Acquired Resistance (SAR), a SAR-inducing infection in one leaf initiates movement of phloem-mobile signals to uninfected distant leaves to prime plants to respond in a resistant manner to subsequent infections. Our early work with the dir1-1 (defective in induced resistance) mutant in Arabidopsis demonstrated that the DIR1 protein is required for SAR and led to the hypothesis that DIR1, a lipid transfer protein (LTP), moves to …