Centennial Honors College Western Illinois University Undergraduate Research Day 2012 Poster Presentation The Expression of JAR1 Genes in an Arabidopsis Mutant, atToc132/120 (+/-) Michelle Golz Faculty Mentor: Dr. Meshack Afitlhile Biology Jasmonic acid (JA) is a plant hormone that accumulates at high level in plants that are wounded or eaten by herbivores. JA synthesis begins in the chloroplast and is completed in the peroxisomes, after which JA is transported to the cytoplasm where jasmonate resistant enzyme 1 (JAR1) conjugates isoleucine (Ile) and JA to form JA-Ile. The initial steps in the JA pathway, which occur in the chloroplasts, require nuclearencoded and cytoplasm synthesized enzymes, which are imported into the chloroplasts in a process that is facilitated by receptors. In Arabidopsis, several chloroplast receptors have been identified and studied in details and these include the Toc159 family of receptors such as atToc159, atToc132 and atToc120. The atToc132 and atToc120 are found in the same complex and they recognize, bind and import housekeeping proteins. In this study, we will evaluate the ability of the atToc132/120 (+/-) mutant to synthesize 12-oxo-phytodienoic acid (OPDA), an intermediate in the JA pathway that is transported from the chloroplasts to the peroxisomes. If the mutant does not accumulate OPDA, then JA will not be synthesized and JAR1 will have no substrate to conjugate to Ile. In this study, we will measure the abundance of mRNA for JAR1 and JA responsive gene, PDF1.2 in both the wounded and unwounded tissues of the mutant and wild type.