Boston University Department of Biology

Faculty Profiles

Current Research

In the plant kingdom the amino acid tryptophan not only functions in protein synthesis, but is also a precursor for a variety of natural products involved in growth and development and in plant defense. In addition, because tryptophan is an essential amino acid, the human diet optimization of its production in plants is an important agricultural trait. Using the mustard Arabidopsis thaliana as a model system, we combine genetic, molecular biological, and biochemical methods to study how tryptophan is converted to the growth hormone auxin, the antiherbivory class of compounds called glucosinolates, and the antifungal compound called camalexin. Our goals are to:

1. define the genes and enzymes needed for the biosynthesis of tryptophan and its metabolites

2. understand regulatory mechanisms that modulate tryptophan metabolism and that integrate these pathways with other metabolic pathways

3. determine the effects of genetic perturbations in tryptophan metabolism on plant growth and development

Courses Taught

• BI 206/282 Genetics
• BI 308 Genetics Laboratory

Selected Publications

• Ljung, K, Hull AK, Celenza JL, Yamada M, Estelle M, Normanly J, Sandberg G (2005). Sites and regulation of auxin biosynthesis in Arabidopsis roots. Plant Cell 17, 1090-1104.
• Celenza, JL, Quiel JA, Smolen GA, Merrikh H, Silvestro A, Normanly J, Bender J (2005). The Arabidopsis ATR1 Myb transcription factor controls indolic glucosinolate homeostasis. Plant Physiol.  137, 253-262.
• DiDonato RJ, Arbuckle E, Buker S, Sheets J, Tobar J, Totong R, Grisafi P, Fink GR, Celenza JL (2004). Arabidopsis ALF4 encodes a nuclear-localized protein required for lateral root formation. Plant J. 37, 340-353.
• Zhao Y, Hull AK, Gupta NR, Goss K, Normanly J, Chory J, Celenza JL (2002). Trp-dependent auxin biosynthesis in Arabidopsis: involvement of cytochrome P450s CYP79B2 and CYP79B3. Genes Dev. 16, 3100-3112.
• Ljung K, Hull AK, Kowalczyk M, Marchant A, Celenza JL, Cohen JD, Sandberg G (2002). Biosynthesis, conjugation, catabolism and homeostasis of indole-3-acetic acid in Arabidopsis thaliana Plant Mol. Biol. 49, 249-272.
• Celenza JL. (2001). Natural products derived from the N-hydroxylation of tyrosine and tryptophan. Curr. Opin. Plant Biol. 4, 234-240.
• Hull AK, Vij R, Celenza JL (2000). Arabidopsis cytochrome P450s that catalyze the first step of tryptophan-dependent indole-3-acetic acid biosynthesis. Proc. Natl. Acad. Sci. USA 97, 2379-2384.
• Hull AK, Celenza JL (2000). Bacterial expression and purification of the Arabidopsis NADPH-cytochrome P450 reductase ATR2. Protein Expr. Purif. 18, 310-315.