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B.S., 1997, Biology and Chemistry, Valparaiso University, Valparaiso, IN
Ph.D., 2002, Biochemistry and Cell Biology, Rice University, Houston, TX
My research focuses on peroxisomal function and its role in auxin metabolism in the model plant Arabidopsis thaliana. I am studying the role of indole-butyric acid (IBA) in auxin response and its relationship to the principle auxin, indole-acetic acid (IAA). IBA is used widely in horticultural settings because of its efficacy at inducing secondary roots on cuttings, but the molecular mechanisms of IBA action are unknown. One hypothesis is that IBA functions as a slow-release form of IAA, providing free IAA for root initiation. Our results indicate this process may occur in a pathway similar to fatty acid -oxidation in peroxisomes.
I have taken a genetic approach to elucidate the mechanisms of IBA function. My work has focused on two groups of IBA-response mutants:
1) Mutants defective in peroxisomal biogenesis or function. These mutants have defects in peroxins, which disrupt peroxisomal biogenesis or import, or in proteins acting within the peroxisome matrix, affecting specific pathways including fatty acid -oxidation and valine catabolism.
2) Mutants with IBA-response defects. These mutants do not have general peroxisome-defective phenotypes, indicating they may be defective in enzymes that act specifically on IBA.
Future work using genetics, cell biology, and biochemistry will reveal how IBA action is important for auxin responses in plants, the enzymes that convert IBA to IAA, and may eventually allow manipulation of species that do not effectively respond to IBA. In addition, this work provides an unbiased approach to explore the specifics of peroxisomal fatty acid metabolism in plants.
Funding: The Zolman lab gratefully acknowledges NSF for funding. Award.
Khan, B.R., Adham, A.R., and Zolman, B.K. (2012) Peroxisomal Acyl-CoA oxidase 4 activity differs between Arabidopsis accessions. Plant Molecular Biology 78:45-58. Article
Khan, B.R. and Zolman, B.K. (2010) pex5 mutants that differentially disrupt PTS1 and PTS2 peroxisomal matrix protein import in Arabidopsis. Plant Physiology 154:1602-15. Article.Article
Zolman, B.K., Martinez, N., Millius, A., Adham, A.R., and Bartel, B. (2008) Identification and Characterization of Arabidopsis Indole-3-Butyric Acid Response Mutants Defective in Novel Peroxisomal Enzymes. Genetics. 180:237-251. Article
Delker, C.*, Zolman, B.K.*, Miersch, O., and Waternack, C. (2007) Jasmonate biosynthesis in Arabidopsis thaliana requires peroxisomal beta-oxidation enzymes - Additional proof by properties of pex6 and aim1. Phytochem. 68, 1642-1650. Abstract
Zolman, B.K., Nyberg, M., and Bartel, B. (2007) IBR3, a novel peroxisomal acyl-CoA dehydrogenase-like protein required for indole-3-butyric acid response. Plant Mol Biol. 64, 59-72. Abstract
Zolman, B.K., Monroe-Augustus, M., Silva, I.D., and Bartel, B. (2005) Identification and functional characterization of Arabidopsis PEROXIN4 and the interacting protein PEROXIN22. Plant Cell 17, 3422-3435. Article
Adham, A.R., Zolman, B.K., Millius, A., and Bartel, B. (2005) Mutations in Arabidopsis thaliana acyl-CoA oxidase genes reveal overlapping and distinct roles in -oxidation. Plant J. 41, 859-874. Abstract
Zolman, B.K. and Bartel, B. (2004) An Arabidopsis indole-3-butyric acid-response mutant defective in PEROXIN6, an apparent ATPase implicated in peroxisomal function. Proc. Natl. Acad. Sci. USA 101, 1786-1791. Article
Monroe-Augustus, M., Zolman, B.K., and Bartel, B. (2003) IBR5, a dual-specificity phosphatase-like protein modulating auxin and abscisic acid responsiveness in Arabidopsis. Plant Cell 15, 2979-2991. Article
Bartel, B., LeClere, S., Magidin, M., and Zolman, B.K. (2001) Inputs to the active indole-3-acetic acid pool: de novo synthesis, conjugate hydrolysis, and indole-3-butyric acid -oxidation. J. Plant Growth Regul. 20, 198-216. (review article)
Zolman, B.K., Silva, I.D., and Bartel, B. (2001) pxa1, an Arabidopsis -oxidation mutant, is defective in a protein required for the peroxisomal import of both fatty acids and indole-3-butryic acid. Plant Physiol. 127, 1266-1278. (featured on the cover) Article
Zolman, B.K., Monroe-Augustus, M., Thompson, B., Hawes, J.W., Krukenberg K.A., Matsuda, S.P.T., and Bartel, B. (2001) chy1, an Arabidopsis mutant with impaired -oxidation, is defective in a peroxisomal -hydroxyisobutyryl-CoA hydrolase. J. Biol. Chem. 276, 31037-31046. Article
Zolman, B.K., Yoder, A., and Bartel, B. (2000) Genetic analysis of indole-3-butyric acid responses in Arabidopsis thaliana reveals four mutant classes. Genetics 156, 1323-1337. Article