Plant defense against pathogens: The role of salicylic acid

Increasing demand for the global food production in the agricultural sector is a crucial driving force for the development of new disease-management methods that are not only effective against known pathogens, but also to the ones that will evolve. Plants possess specialized structures, chemicals and sophisticated mechanisms to defend themselves from pathogens. Understanding these defense mechanisms and pathways are critical for developing innovative approaches to protect crop plants from diseases as pathogens are continually evolving intricate means of breaching plant defenses. Plant defense pathways involve a number of signaling compounds that regulate the production of defense-related chemicals. These pathways are strongly connected with salicylic acid (SA), ethylene (ET), jasmonic acid (JA) and abscisic acid (ABA). The compound that is in the center of interest in this review article is salicylic acid due to its involvement in a variety of functions including biotic and abiotic stress management in plants. The adverse effects of overuse of pesticides have led to the development and adoption of genetically engineered crops including those expressing genes involved in SA mediated defense pathways for enhanced defense capabilities, higher yields under biotic stress with reduced use of harmful pesticides. This review article focuses on latest developments in the plant-pathogen interaction and in particular, on the functional role played by salicylic acid in plant defense. A better understanding of plant defense mechanisms will enable scientists to develop more efficient methods of protecting plants from pathogens for sustainable agriculture.