Molecular and Biochemical Signaling Underlying Arabidopsis-Bacterial/Virus/Fungal Interactions

• Main Author: El-Shetehy, Mohamed H.
• Format: Others
• Published: UKnowledge 2016
• Subjects: Systemic acquired resistance; Azelaic acid; Glycerol-3-phosphate; Nitric oxide; Reactive oxygen species; Bacteriology; Biochemistry; Biotechnology; Microbiology; Molecular Biology; Virology
• Online Access: http://uknowledge.uky.edu/plantpath_etds/19; http://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1019&context=plantpath_etds

Systemic acquired resistance (SAR) is a form of inducible defense response triggered upon localized infection that confers broad-spectrum disease resistance against secondary infections. Several factors are known to regulate SAR and these include phenolic phytohormone salicylic acid (SA), phosphorylated sugar glycerol-3-phosphate (G3P), and dicarboxylic acid azelaic acid (AzA). This study evaluated a role for free radicals nitric oxide (NO) and reactive oxygen species (ROS) in SAR. Normal accumulation of both NO and ROS was required for normal SAR and mutations preventing NO/ROS accumulation and/or biosynthesis compromised SAR. A role for NO and ROS was further established using pharmacological approaches. Notably, both NO and ROS conferred SAR in a concentration dependent manner. This was further established using genetic mutants that accumulated high levels of NO. NO/ROS acted upstream of G3P and in parallel to SA. Collectively, these results suggest that NO and ROS are essential components of the SAR pathway.