Identification and Characterization of Novel Auxin Biosynthetic Mutants

Indole-3-acetic acid (IAA) is the primary form of auxin in plants and several IAA biosynthetic pathways have been previously proposed but remain genetically uncharacterized. One of the existing pathways is the indole-3-pyruvic acid (IPyA) pathway, which is known to regulate key developmental processes such as apical hook formation and shade avoidance. Recent studies suggest the existence of the pathway in higher plants but are unverified due to the elusive nature of IPyA in vitro. Extending on these recent advances, this research was aimed at investigating aspects of IPyA-dependent auxin biology in Pisum sativum (pea) using reverse genetics. Consequently, using a reverse genetic approach, called TILLING, the PsTAR2 gene was mutated in order to study firsthand the downstream effects of IPyA deficiency. The procedure resulted in isolating two novel PsTAR2 (IPyA) mutant lines consisting of a missense mutation (PsTAR2 4280) and a highly desired knockout mutation (PsTAR2 918). The novel mutants are anticipated to be indispensable to future IPyA-auxin investigations in higher plants.