KSEF RDE: Pipecolic Acid-Mediated Defense Signaling in Plants

Pipecolic acid (Pip), a non-proteinacious product of lysine catabolism, is an important regulator of immunity in plants and humans alike. For instance, Pip accumulation is associated with the genetic disorder Zellweger syndrome, chronic liver diseases, andpyridoxine-dependent epilepsy in humans. In plants, Pip accumulates upon pathogen infection and is required for plant defense. The aminotransferase ALD1 catalyzes biosynthesis of Pip precursor piperideine-2-carboxylic acid (P2C), which is converted to Pip via ornithine cyclodeaminase. Another enzyme sarscosine oxidase (SOX) isthought to convert Pip to piperideine-6-carboxylic acid (P6C). Intriguingly, a mutation in either ALD1 or SOX1 compromises plant defense, even though Pip levels were only affected in ald1 plants. This proposal will characterize Pip metabolism in plants and decipher relative roles of P2C and P6C in plant defense. RNA seq analysis of plants treated with Pip has identified an important role for redox signaling in Pip metabolism. This proposal will also characterize the role of Pip associated redox components in host-pathogen interaction.