Abstract: In recent years there has been a large body of evidence to suggest that plants have a variety of active mechanisms for defending themselves against microbial pathogenic infections. The development of systemic acquired resistance (SAR) and its signal transduction pathway are associated with increased expression of a large number of defense or defense-related genes. Salicylic acid (SA) is an important signaling molecule in the induction of disease resistance and the establishment of SAR in plants. There have been two kinds of possible mechanisms in the establishment of SAR and its signal transduction pathway among plants.

Key words: Systemic acquired disease resistance, Signal transduction, Systemic acquired resistance proteins, Salicylic acid