Salicylic acid (SA) has been shown to play a critical role in signaling the activation of plant defense responses following pathogen infection. These responses include the induction of cell death and disease resistance in the infected leaf, as well as the activation of systemic disease resistance in the uninfected portions of the plant. SA has been shown to induce these phenomena through a variety of mechanisms that may include altering the activity or synthesis of certain enzymes, increasing the expression of various defense genes and/or potentiating the activation of certain defense responses.
