Author ORCID Identifier
Year of Publication
Doctor of Philosophy (PhD)
Agriculture, Food and Environment
Dr. Aardra Kachroo
Systemic acquired resistance (SAR), initiated by a plant upon recognition of microbial effectors, involves the generation of mobile signals at the primary infection site, which translocate to and activate defense responses in distal tissues. Among the signals contributing to SAR include salicylic acid (SA), nitric oxide (NO), reactive oxygen species (ROS), glycerol-3-phosphate (G3P), and pipecolic acid (Pip). Our previous studies show there are two branches of SAR signaling pathways in Arabidopsis: one regulated by NO/ROS-G3P and the other by SA. Both NO/ROS-G3P and SA-mediated signaling branches function in parallel during SAR. To better understand the role of Pip in SAR and the molecular mechanisms underlying Pip-mediated signaling, I investigated relationship between Pip and other SAR signals. My results suggest that Pip-mediated SAR is dependent on the NO/ROS-G3P branch of the SAR pathway. This is supported by the results that exogenous Pip increases NO, ROS, and G3P, but not SA. Detailed characterization of Pip metabolism showed that Pip acts upstream of several known and unknown derivatives. I also investigated involvement of ascorbic acid biosynthetic enzymes and several ROS scavenging enzymes in SAR. Together, my results suggest that Pip- and ROS-metabolic pathways regulate key steps of SAR signaling in plants.
Digital Object Identifier (DOI)
Liu, Ruiying, "CHARACTERIZING THE ROLES OF PIPECOLIC ACID AND REACTIVE OXYGEN SPECIES METABOLIC ENZYMES IN PLANT SYSTEMIC IMMUNITY" (2020). Theses and Dissertations--Plant Pathology. 27.