Home Publications People Schedule Projects Teaching Join Us
Genetic analyses of auxin signaling in Arabidopsis
Bonnie Bartel, Professor
Department of Biochemistry and Cell Biology
bartel@rice.edu
Auxins are plant hormones that promote lateral and adventitious root formation, and auxins are widely used in agriculture for this purpose.  However, our understanding of the targets of auxin action within the plant remains incomplete. 

We have found that the ibr5 mutant displays multiple phenotypes suggesting that it responds less than wild type to both exogenous and endogenous auxin.  ibr5 also is less responsive than wild type to abscisic acid. ibr5 contains a nonsense mutation in an apparent dual-specificity phosphatase gene.  We are currently taking several approaches to identify IBR5 substrates and other IBR5-interacting components, which also may modulate auxin responsiveness.

We also are isolating and characterizing mutants specifically defective in responses to particular auxins, auxin-like molecules, and auxin precursors to distinguish between auxin precursors and active auxins.
Lab members with auxin signaling projects:

Post Docs:

Lucia Strader
Andrew Woodward

Graduate Students:

Sarah Ratzel

Undergraduates: 

Erin Beisner
James Liu

Former Graduate Students:

Melanie Monroe-Augustus (Ph.D., 2004)
Luise Rogg (Ph.D., 2001)

We gratefully acknowledge support for this research from the USDA and the NSF, the NIH (NRSA fellowship to LCS), and Houston Livestock Show and Rodeo Scholarships (AW).

Publications on auxin signaling:

Other Bartel lab projects:
Auxin conjugates, IBA, peroxisomes, 
triterpenes, microRNAs

Arabidopsis iba response5 (ibr5) suppressors separate responses to various hormones.
Strader, L.C., Monroe-Augustus, M., Rogers, K.C., Lin, G.L., and Bartel, B. (2008) Genetics180, 2019-2031.
Abstract; full text; PDF

The IBR5 phosphatase promotes Arabidopsis auxin responses through a novel mechanism distinct from TIR1-mediated repressor degradation. 
Strader, L.C., Monroe-Augustus, M., Bartel, B. (2008) BMC Plant Biology 8, 41.
Abstract; full text; PDF

A new path to auxin. 
Strader, L.C, Bartel, B. (2008) Nature Chemical Biology 4, 337-339.
full text

Mutation of E1-CONJUGATING ENZYME-RELATED1 decreases RELATED TO UBIQUITIN conjugation and alters auxin response and development. 
Woodward, A.W., Ratzel, S.E., Woodward, E.E., Shamoo, Y., and Bartel, B.  (2007) Plant Physiology 144, 976-987.
Abstract; full text; PDF

A receptor for auxin.
Woodward, A.W. and Bartel, B. (2005) Plant Cell 17, 2425-2429.
full text

MicroRNA-directed regulation of Arabidopsis AUXIN RESPONSE FACTOR17 is essential for proper development and modulates expression of early auxin response genes.
Mallory, A.C., Bartel, D.P., and Bartel, B. (2005) Plant Cell 17, 1360-1375. (On the cover)
Abstract; full text

Auxin: regulation, action, and interaction. 
Woodward, A.W. and Bartel, B. (2005) Annals of Botany,95, 707-735.
Abstract; full text

An auxin transport independent pathway is involved in phosphate stress-induced root architectural alterations in Arabidopsis. Identification of BIG as a mediator of auxin in pericycle cell activation.
Lopez-Bucio, J., Hernandez-Abreu, E., Sanchez-Calderon,  L., Perez-Torres, A., Rampey, R.A., Bartel, B., and Herrera-Estrella, L. (2005) Plant Physiology 137,681-691.
Abstract; full text

IBR5, a dual-specificity phosphatase-like protein modulating auxin and abscisic acid responsiveness in Arabidopsis. 
Monroe-Augustus, M., Zolman, B.K., and Bartel, B. (2003) Plant Cell 15, 2979-2991.
Abstract; full text; PDF

A gain-of-function mutation in IAA28 suppresses lateral root development. 
Rogg, L.E., Lasswell, J. and Bartel, B. (2001) Plant Cell 13, 465-480.
Abstract; full text; PDF

Auxin signaling: Derepression through regulated proteolysis
Rogg, L.E. and Bartel, B. (2001) Developmental Cell 1, 595-604.  (Review Article)
Abstract; full text; PDF

Biochemistry