CCRC personnel

 

Michael G Hahn

Professor of Plant Biology, Adjunct Professor of Biochemistry and Molecular Biology, and Plant Pathology; UGA Faculty Participant, DOE BioEnergy Science Center


Immunological approaches to plant cell wall structure and biology; plant cell wall polysaccharide biosynthesis

E-mail: hahn@ccrc.uga.edu
Telephone: 706-542-4457
Fax: 706-542-4412
Complex Carbohydrate Research Center
The University of Georgia
315 Riverbend Rd.
Athens, Georgia 30602

Short Biography
Research Interests
keywords and Selected Recent Publications
All Publications
Lab-personal web site

Short Biography:

Dr. Hahn received a B.S. in chemistry and a B.A. in Independent Studies in 1974 from the University of Oregon and his Ph.D. in biochemistry in 1981 from the University of Colorado. A postdoctoral research associate appointment at the University of Wisconsin-Madison in plant pathology followed, after which Dr. Hahn went to the Albert-Ludwigs-Universiät (Freiburg, Germany) with the support of an Alexander-von-Humboldt stipend. Following another postdoctoral research associate appointment at the Salk Institute (San Diego, CA), Dr. Hahn joined the CCRC in July 1986. Full publications: 77.
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Research Interests:

Our laboratory studies the cell biology and biosynthesis of plant cell walls. Plant cell walls play major roles in the biology of plants. Examples of these roles include controlling the growth and shape of plant cells, tissues, organs, and ultimately the entire plant, regulating the movement of nutrients and signals within the apoplast and toward the plasma membrane, serving as the first line of defense against pathogens and environmental stresses, and acting as a source of signaling molecules important in plant development and defense. Plant cell walls are also the principal component of plant biomass, which has become a focal point in the search for alternative and renewable sources of energy (biofuels).

We are pursuing two broad research goals:

(A) We are investigating plant cell wall biosynthesis by looking at two families of genes, primarily in Arabidopsis, thought to encode glycosyltransferases involved in plant cell wall glycan biosynthesis: 1) GAlacturonosylTransferase-Like (GATL) proteins thought to be involved in pectin biosynthesis; 2) FUcosylTransferase (FUT) proteins thought to add fucosyl residues to diverse plant cell wall glycans.

(B) We have developed a large and diverse library of monoclonal antibodies against plant cell wall glycans. These antibodies are being used to determine the locations of diverse cell wall carbohydrate structures (epitopes) in Arabidopsis, switchgrass and poplar. These antibodies are also proving useful for plant cell wall mutant characterization studies, and for quantitating glycans in cell wall extracts.

Our laboratory utilizes a broad range of experimental approaches in these studies, including molecular genetic, biochemical, immunological and microscopic techniques.


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Keywords and Selected Recent Publications:

Keywords:Plant cell wall, polysaccharide biosynthesis, glycosyltransferases, immunolocalization, monoclonal antibodies, glycome profiling, signal transduction, oligosaccharin.

Selected Publications:

Sterling, J.D., M.A. Atmodjo, S.E. Inwood, V.S.K. Kolli, H.F. Quigley, M.G. Hahn and D. Mohnen. 2006. Functional identification of an Arabidopsis pectin biosynthetic homogalacturonan galacturonosyltransferase. Proc. Natl. Acad. Sci. 103: 5236-5241.

Pessoni, R.A.B., G. Freshour, R.C.L. Figueiredo-Ribeiro, M.G. Hahn and M.R. Braga. 2005. Cell wall structure and composition of Penicillium janczewski Zaleski as affected by different carbon sources. Mycologia 97: 304-311.

Simões, K., S.M.C. Dietrich, M.G. Hahn and M.R. Braga. 2005. Purification and characterizaton of a phytoalexin elicitor from spores of the saprobe Mucor ramosissimus. Revista Brasil Bot. 28: 735-744.

Freshour, G., C.P. Bonin, W.-D. Reiter, P. Albersheim, A.G. Darvill and M.G. Hahn. 2003. Distribution of fucose-containing xyloglucans in cell walls of the mur1 mutant of Arabidopsis thaliana. Plant Physiol. 131: 1576-1577.

Bonin, C.P., G. Freshour, M.G. Hahn, G. Vanzin and W.-D. Reiter. 2003. The GMD1 and GDM2 genes of Arabidoposis thaliana encode isoforms of GDP-D-mannose 4,6-dehydratase with cell type-specific expression patterns. Plant Physiol. 132: 883-892.

Zhong, R., J.W. Morrison, G.D. Freshour, M.G. Hahn and Z.-H. Ye. 2003. Expression of a mutant form of cellulose synthase AtCesA7 causes dominant negative effect on cellulose biosynthesis. Plant Physiol. 132: 786-795.

Pessoni, R.A.B., G. Freshour, R.C.L. Figueiredo-Ribeiro, M.G. Hahn and M.R. Braga. 2002. Woronin bodies in Penicillium janczewskii Zaleski. Brasilian J. Microbiol. 33: 127-130.

Ye, Z.-H., G. Freshour, M.G. Hahn, D.H. Burk and R. Zhong. 2002. Vascular development in Arabidopsis. Int. Rev. Cytol. 220: 225-256.

Côté, F., K.A. Roberts and M.G. Hahn. 2001. Identification of high-affinity binding sites for the hepta-b-glucoside elicitor in membranes of the model legumes Medicago truncatula and Lotus japonicus. Planta 211: 596-605.

Moraes, F., M.G. Hahn and M.R. Braga. 2001. Comparative analysis of leaf cell-wall polysaccharides of Dialypetalanthus fuscescens and Bathysa meridionalis: evidence of biochemical similarities between Dialypetalanthaceae and Rubiaceae-Cinchonoideae. Rev. Brasil. Botan. 24: 289-294.

Fleck, J., W.K. Fitt and M.G. Hahn. 1999. A proline-rich peptide originating from decomposing mangrove leaves is one natural metamorphic cue of the tropical jellyfish Cassiopea xamachana. Mar. Ecol. Prog. Ser. 183: 115-124.

Geurtsen, R., F. Côté, M.G. Hahn and G.-J. Boons. 1999. A novel chemoselective glycosylation strategy for the rapid convergent assembly of phytoalexin-elicitor active oligosaccharides and their photo-reactive derivatives. J. Org. Chem. 64: 7828-7835.

Côté, F., K.-S. Ham, M.G. Hahn and C.W. Bergmann. 1998. Oligosaccharide elicitors in host-pathogen interactions: Generation, perception and signal transduction. In: B.B. Biswas and H. Das (eds.), Subcellular Biochemistry, Vol. 29, Plant-Microbe Interactions, pp. 385-432. Plenum Publishing Corp., New York, NY.

Enkerli, K., M.G. Hahn and C.W. Mims. 1997. Ultrastructure of compatible and incompatible interactions of soybean roots infected with the plant pathogenic oomycete Phytophthora sojae. Can. J. Bot. 75: 1493-1508.

Enkerli, K., M.G. Hahn and C.W. Mims. 1997. Immunogold localization of callose and other plant cell wall components in soybean roots infected with the plant pathogenic oomycete Phytophthora sojae. Can. J. Bot. 75: 1509-1517.

Hahn, M.G. 1996. Microbial elicitors and their receptors in plants. Annu. Rev. Phytopath. 34: 387-412.

Freshour, G., R. Clay, M.S. Fuller, P. Albersheim, A.G. Darvill and M.G. Hahn. 1996. Developmental and tissue-specific structural alterations of the cell-wall polysaccharides in Arabidopsis thaliana roots. Plant Physiol. 110: 1413-1429.

Williams, M.N.V., G. Freshour, A.G. Darvill, P. Albersheim and M.G. Hahn. 1996. An antibody Fab selected from a recombinant phage display library detects deesterified pectic polysaccharide rhamnogalacturonan II in plant cells. Plant Cell 8: 673-685.

Steffan, W., P. Kovác, P. Albersheim, A.G. Darvill and M.G. Hahn. 1995. Characterization of a monoclonal antibody that recognizes an arabinosylated (1,6)-ß-D-galactan epitope in plant complex carbohydrates. Carbohyd. Res. 275: 295-307.

Puhlmann, J., E. Bucheli, M.J. Swain, N. Dunning, P. Albersheim, A.G. Darvill and M.G. Hahn. 1994. Generation of monoclonal antibodies against plant cell wall polysaccharides. I. Characterization of a monoclonal antibody to a terminal alpha-(1,2)-linked fucosyl-containing epitope. Plant Physiol. 104: 699-710.

Cheong, J.-J., R. Alba, F. Côté, J. Enkerli and M.G. Hahn. 1993. Solubilization of functional plasma membrane-localized hepta-ß-glucoside elicitor-binding proteins from soybean. Plant Physiol. 103: 1173-1182.
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