Supported by the NSF IBN Program and the NIH


Auxin is an essential plant hormone that regulates diverse processes, such as cell division and expansion, embryogenesis, meristem formation, root and leaf patterning, tropism, and reproduction. Extensive molecular studies have identified a large set of auxin inducible genes and the auxin responsive cis-elements and the relevant trans-acting factors. Genetic approaches have led to the isolation of genes involved in auxin responses and transport and the unraveling of protein degradation control in auxin signaling.


Our lab has been interested in understanding the molecular and biochemical mechanisms underlying the auxin signal transduction pathway that control nuclear gene transcription and plant morphogenesis. We have taken novel molecular genetic and genomic approaches to identify regulatory genes important for auxin-inducible transcription and morphogenesis by using tobacco and Arabidopsis as model systems. We have established efficient transient and stable transformation systems that will allow the identification of genes that can perturb (both gain-of-function and loss-of-function) various steps of the auxin- dependent transcription and morphogenesis, including cell proliferation, elongation, and differentiation. These expression cloning and functional genomic analysis methods could facilitate the identification of genes involved in cell shape, growth polarity, cell division, cell death, organogenesis, embryogenesis and gene expression. The use of the jellyfish green-fluorescent protein (GFP) provides an excellent visual marker to follow auxin responses in living cells. The experimental design can overcome lethality and functional redundancy, which may limit the isolation of more specific mutants important for the elucidation of the auxin signal transduction pathway.


Based on the control of early response gene transcription, we have explored the functions of mitogen activated protein kinase (MAPK) signaling cascades in the regulation of auxin responses. We have discovered both positive and negative roles of MAPK cascades in auxin signaling. The future goals are to define the specific roles of each molecular component and their upstream regulators and downstream targets. In addition, our studies have revealed surprising connections between auxin and stress signaling as well as auxin and sugar signaling in plants. The identification of molecular links connecting auxin and sugar, stress or cytokinin signaling networks will reveal a complex but more realistic view of regulatory circuits in plant cells. The studies have provided novel approaches to manipulate plant life span, seed development, and vegetative and reproductive growth for the improvement of crop yield.


Signaling Pathway Illustrations

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powerpoint presentation

Plant signaling

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Yoo, S.D., Cho, Y.H.,, and Sheen, J. 2009. Emerging connections in the ethylene-signaling network. Trends in Plant Science. 14: 270-279.PDF

Ramon, M., Rolland, F., and Sheen, J. October 22, 2008 Sugar Sensing and Signaling. The Arabidopsis Book (TAB), ISSN: 1543-8120   pages 1-22 PDF

Rolland, F., Gonzalez, E.B., and Sheen, J. 2006. Sugar Sensing and Signaling in Plants: Conserved and Novel Mechanisms. Annual Review of Plant Biology Volume 57: 676-709. PDF

Rolland, F., Moore, B., and Sheen, J. 2002. Plant sugar sensing and signaling. Plant Cell 14: S185-S205.

Cheng, S.-H., Willmann, M. R., Chen, H.-C. and Sheen. J. 2002. Calcium Signaling through Protein Kinases: The Arabidopsis Calcium-Dependent Protein Kinase Gene Family, Plant Physiol. 129: 469-485.

Sheen, J. 2002. Phosphorelay and transcription control in cytokinin signal transduction. Science, 296: 1650-1652.

Sheen, J. 2001. Signal transduction in maize and Arabidopsis mesophyll protoplasts. Plant Physiol. 127:1466-1475. A special issue on plant systems. PDF

Tena, G., Asai, T., Chiu, W.-L., and Sheen, J. 2001. Plant mitogen-activated protein kinase signaling cascades. Curr. Opin. Plant Biol. 4:392-400 PDF

Sheen, J., Zhou, L., and Jang, J.-C. 1999. Sugar as a signaling molecule. Curr. Opin. Plant Biol. 2:410-418.

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Shan, L., He, P., Li, J., Heese, A., Peck, S.C., Nürnberger, T., Martin, G.B. and Sheen, J. 2008. Bacterial Effectors Target the Common Signaling Partner BAK1 to Disrupt Multiple MAMP Receptor Signaling Complexes and Impede Plant Immunity. Cell Host & Microbe 4: 17-27 PDF  SUPP

Müller, B. and Sheen, J. 2008. Cytokinin and auxin interaction in root stem-cell specification during early embryogenesis. Nature 453: 1094-1097 PDF  SUPP

Yoo, S-D., Cho Y-H., Tena G., Xiong. Y. and Sheen, J. 2008. Dual control of nuclear EIN3 by bifurcate MAPK cascades in C2H4 signalling. Nature 451: 789-795 PDF  SUPP

Chen, Z., Agnew, J.L., Cohen, J.D., He, P., Shan, L., Sheen, J. and Kunkel, B.N. 2007. Pseudomonas syringae type III effector AvrRpt2 alters Arabidopsis thaliana auxin physiology. PNAS 104: 20131-20136 PDF

Moore, B., Zhou, L.,Rolland, F., Hall, Q., Cheng, W.-H., Liu, Y.-X., Hwang, I., Jones, T., Sheen, J. 2003. Role of the Arabidopsis Glucose Sensor HXK1 in Nutrient, Light, and Hormonal Signaling. Science 300: 332-336 Abstract Full Text SUPP.

Hwang, I. and Sheen, J. 2001. Two-component circuitry in Arabidopsis cytokinin signal transduction. Nature 413(6854):383-9 PDF

Kovtun, Y., Chiu, W.-L. Tena, G., and Sheen, J. 2000. Functional analysis of oxidative stress-activated MAPK cascade in plants. PNAS. 97: 2940-2945.

Jang, J., Fujioka, S., Tasaka, M., Seto, H., Takatsuto, S., Ishii, A., Aida, Yoshida, S., Sheen, J. 2000. A critical role of sterols in embryonic patterning and meristem programming revealed by the fackel mutants of Arabidopsis thaliana. Genes & Dev. 14: 1485-1497.

Kovtun, Y., Chiu, W.-L. Zeng, W. and Sheen, J. 1998. Suppression of auxin signal transduction by a MAPK cascade in higher plants. Nature 395: 716-720.

Chiu, W.-L. , Niwa, Y, Zeng, W, Hirano, T., Kobayashi, H, Sheen, J. 1996. Engineered GFP as a vital reporter in plants. Current Biol. 6: 325-330.

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