We use Arabidopsis mutants to identify genes providing inputs to the auxin pool, to distinguish precursors from active auxin, and to disentangle contributions of different auxin biosynthetic pathways to development. We have isolated Arabidopsis mutants resistant to auxin
storage forms (including the IAA-amino acid conjugates IAA-Ala
and IAA-Leu) that remain sensitive to free IAA.
Two of these mutants, ilr1 and iar3, led to the discovery of enzymes that can release free
IAA from conjugates. In contrast, ilr2, ilr3,
iar1, and mtp5 defects uncovered a role for metal homeostasis
in auxin metabolism.
We currently are working to identify the genes defective
in additional conjugate response mutants and using these
mutants to elucidate the importance of various auxin
storage forms during plant development.
Lab members with conjugate projects:
Former Graduate Students:
Haifeng Chen (M.A., 1999)
Jamie Lasswell (Ph.D., 2000)
Sherry LeClere (Ph.D., 2002)
Mónica Magidin (Ph.D., 2002)
Rebekah Rampey (Ph.D., 2004)
Andrew Woodward (Ph.D., 2005)
Luise Rogg (Ph.D., 2001)
Rosie Tellez (1995-2001)
We gratefully acknowledge support
for this research from the NIH, the Robert A. Welch Foundation,
a NIH Training Grant (T32-GM08362; SL), and Houston Livestock
Show and Rodeo Scholarships (RR, SL, JL, RT).
Compensatory mutations in predicted metal transporters modulate auxin conjugate responsiveness in Arabidopsis.
Rampey, R.A., Baldridge, M.T., Farrow, D.C., Bay, S.N., and Bartel, B. (2013) G3: Genes, Genomes, Genetics 3, 131-41.
Abstract; full text; PDF
An Arabidopsis basic helix-loop-helix leucine zipper protein modulates metal homeostasis and auxin conjugate responsiveness.
Rampey, R.A., Woodward, A.W., Hobbs, B.N., Tierney, M.P., Lahner, B., Salt, D.E., and Bartel, B. (2006) Genetics 174, 1841-1857.
Abstract; full text
Auxin: regulation, action, and interaction.
Woodward, A.W. and Bartel, B. (2005) Annals of Botany 95, 707-735. (Review Article)
Abstract; full text
family of auxin-conjugate hydrolases that contribute to free indole-3-acetic
acid levels during Arabidopsis germination.
Rampey, R.A., LeClere, S., Kowalczyk, M.,
Ljung, K., Sandberg, G., and Bartel, B. (2004) Plant Physiology 135, 978-988.
a gene required for auxin conjugate sensitivity in Arabidopsis,
encodes a pyruvate dehydrogenase E1a homolog.
LeClere, S., Rampey, R.A., and Bartel, B.
(2004) Plant Physiology 135, 989-999.
a novel gene involved in IAA conjugate sensitivity and metal transport
in Arabidopsis thaliana.
Magidin, M., Pittman, J.K., Hirschi, K.D.,
and Bartel, B. (2003) The Plant Journal 35, 523-534.
of a family of IAA-amino acid conjugate hydrolases from Arabidopsis
LeClere, S., Tellez, R., Rampey, R.A., Matsuda,
S.P.T., and Bartel, B. (2002) Journal of Biological Chemistry 277, 20446-20452.
to the active indole-3-acetic acid pool: de novo synthesis,
conjugate hydrolysis, and indole-3-butyric acid b-oxidation.
Bartel, B., LeClere, S., Magidin, M., and
Zolman, B.K. (2001) Journal of Plant Growth Regulation 20,
198-216. (Review Article)
and characterization of IAR1, a gene required for auxin conjugate
sensitivity in Arabidopsis.
Lasswell, J., Rogg, L.E., Nelson, D.C., Rongey,
C., and Bartel, B. (2000) Plant Cell 12, 2395-2408.
IAR3 encodes an auxin conjugate hydrolase from Arabidopsis.
Davies, R.T., Goetz, D.H., Lasswell, J., Anderson,
M.N., and Bartel, B. (1999) Plant Cell 11, 365-376.
as a way of life - IAA metabolism.
Normanly, J. and Bartel, B. (1999) Current
Opinion in Plant Biology 2, 207-213. (Review Article)
Bartel, B. (1997) Annual Review of Plant
Physiology and Plant Molecular Biology 48, 51-56. (Review