2013 REU Poster: Modulation of Indolic Plant Defense compound Synthesis by Tryptophan Analogs

Abstract

Like bacteria and fungi, plants are able to synthesize aromatic amino acids Tyrosine (Tyr), Phenylalanine (Phe) and Tryptophan (Trp). Those amino acids are used in plants not only for protein synthesis, but also for a variety of compounds that control development and defense. Arabidopsis thaliana uses Trp to produce distinct secondary metabolites that function as deterrents to herbivory (indole glucosinolates), as defense against microbial pathogens (camalexin) and as growth regulators(indole-3-acetic acid). To better understand the relationship between Trp biosynthesis and indole glucosinolate (IGs) production, we have tested different analogs of Trp on Columbia, a wild-type Arabidopsis accession. We have found that alpha-methyl tryptophan cannot be incorporated into IGs and in fact inhibits IG synthesis.