Stress Alleviation in Plants Using SAR and ISR: Current Views on Stress Signaling Network

Abstract

Plants are armored with several defense mechanisms that are inducible in the presence of stress stimuli to protect them from pathogen attack, insect mediated herbivory or to increase systemic tolerance towards abiotic stimuli such as heat, light, cold, mechanical injuries, etc. These inducible defenses include multifaceted molecular, biochemical, and morphological changes. SAR and ISR are the two forms of induced resistance pathways in which the plant defense system is hiked up against a variety of pathogens as well as abiotic stresses. Plant defenses are usually preconditioned by previous encounter with the pathogens. Molecular and biochemical studies have revealed the elicitors mediating both types of responses. These elicitors are commercially available and commonly used in conventional agriculture practices for disease management. Research on SAR and ISR over the past few years has elaborated the understanding of the mechanism of entire process at molecular level. Use of PGPR as well as exploiting ISR and SAR machineries for disease management proves to be a promising alternative for environmentally malignant chemical pesticides. This chapter summarizes response pathways of plants under stress conditions, role of ROS (Reactive Oxygen Species), metabolic cues including hormones involved in signaling cascade, and mechanisms of systemic protection in plants.