Professor of Plant Biology

Purdue University
Botany and Plant Pathology, Lilly Hall
915 West State Street
West Lafayette, IN 47907-2054

Office:  LILY 1-415
Phone:  (765) 494-4653
FAX:      (765) 494-0363
E-mail:   

Area: Plant Cell Biology - Structure and biosynthesis of the plant cell wall; gene discovery in cell wall biology; improvement of grasses as lignocellulosic bioenergy crops

Education

Ph.D., Colorado State University, Plant Physiology, 1977

Research Interests

We research the biochemistry and molecular biology of cell wall formation during cell development. Current programs include:

• The biosynthesis of the maize mixed-linkage (1→3),(1→4)ß-D-glucan in vitro
• Characterization of the cellulose synthase and cellulose synthase-like genes of cereals
• Characterization of cell wall mutants in arabidopsis
• Cellular aspects of phloem fiber initiation and development in flax
• Determinants of cell-cell adhesion and wall softening during fruit ripening
• Determinants of membrane-wall adhesion in response to osmotic stress
• Novel inducible promoters in plants
• Fourier transform infrared spectroscopy as a high through-put screen for cell wall mutants in arabidopsis and maize.

Khaldoun Al-Hadid Pectin is a class of acidic plant cell wall polysaccharides that represents a major fraction of the Type I primary cell wall typical of dicots. Galacturonic acid residues of pectin can be acetylated at the C2 and C3 positions.  The enzyme pectin acetyl esterase can specifically hydrolyze such acetyl esters in homogalacturonan regions of pectin.  Using pectin acetyl esterase (PAE) on pectin gels in vitro alters their physical properties.  Thus, I hypothesize that PAE may affect cell wall mechanical properties in vivo by regulating the degree of pectin acetylation. Eleven putative genes have been identified in the Arabidopsis genome to be encoding pectin acetyl esterase.  I propose to carry out a functional analysis for selected members of this gene family.  I will express one of the eleven genes in Drosophila cell lines in order to verify that this gene encodes a PAE activity.  Gain-of- function experiments (over-expression of PAE genes) and loss-of-function experiments (RNAi and the use of insertional mutants) will be used to alter PAE activity in cell walls of Arabidopsis and, therefore, to alter the degree of pectin acetylation.

Dr. Michael A. Held Unique to the Poales order which includes the cereals: barley, oat, wheat, rice, and maize are the mixed-linkage (1→3), (1→4) ß-glucans (b-glucan).  b-Glucans are unbranched polymers composed mostly of cellotriose and cellotetraose oligomers connected by single ß-(1→3) linkages and are synthesized at the Golgi membrane from UDP-glucose substrates in cells undergoing rapid elongation growth as well as the endosperm cells by the ß-glucan synthase complex.  Nascent polymers are targeted to the cell wall via secretory vesicles, and then are deposited into the walls where they are principally associated with cellulose microfibrils.  As the active component of soluble dietary fiber, ß-glucans are responsible for lowering blood cholesterol and modulating insulin uptake and thus play an important role in our diets.  My work has been focused on identifying the genes which encode the glycosyltransferases responsible for ß-glucan biosynthesis in plants.  We have taken a two-sided approach toward these ends first by viral-induced gene silencing (VIGS) of select members of the cellulose synthase-like (CSL) gene family in barley and second by proteomic analyses of detergent extracts of intact Golgi harvested from maize coleoptiles.  Members of the CSL gene families are prime candidates for encoding the core biosynthetic machinery for non-cellulosic cell wall polymers such as ß-glucan.  Recent evidence has suggested that a component required for polymerization of ß-glucans, can be extracted from intact maize Golgi using detergents.  Therefore we are examining these detergent extracts by proteomics to identify any accessory components of the ß-glucan synthase complex.

Tiffany Langewisch I am characterizing brittle stalk2 (bk2) and other cell-wall mutants in maize by Fourier transform infrared spectroscopy and biochemical methods.  The maize bk2 is a developmentally programmed mutant phenotype in which all parts of the plant turn suddenly brittle following the 4-leaf stage. Consequently, bk2 plants snap easily, making it hard to grow them unassisted.  A link between the brittle bk2 phenotype and cellulose deficiency has been suggested, as the mutants typically have 20 to 30% less cellulose than the wild type.  Our collaborator, Dr. Guri Johal (Botany & Plant Pathology) has cloned bk2 by transposon tagging with Mutator.  BK2 is related to the rice brittle culm (bc1) that encodes a protein of the COBRA family.  A cellulose deficiency does not fully explain the brittle phenotype and I am using Fourier transform infrared spectroscopy (FTIR) with biochemical and cytological approaches to determine what specific architectural features contribute to the brittle phenotype.

Dr. Radnaa Naran Pectic polysaccharides are some of the most complex polysaccharides in Nature, and determination of their fine structure and function as architectural elements represents a significant challenge.  As part of the Cell Wall Genomics team, I am developing high through-put, sensitive methods to determine the fine structure of pectins and other cell-wall polysaccharides in maize and Arabidopsis.  I am particularly interested in efficient screens employing electrospray and MALDI-TOF MS for mutants with defects in rhamnogalacturonan II structure. During the course of these studies I discovered that certain seed mucilages, typically rich in RG I, have altered polysaccharide structures.  I am using chemical and enzymatic approaches to determine the fine structure of the rare mucilages. I also am characterizing several mutants of the Family 35 ß-galactosidase gene family in Arabidopsis.  These enzymes modify pectic galactans and other galactose containing residues of cell-wall polysaccharides during development, and my aim is to develop assays to determine the substrate specificity to establish functional relationships between genotype and phenotype.

Anna Olek I have been research technician and administrative professional in the Carpita lab for nearly 20 years.  I am currently supervisor of the Cell Wall Genomics Program at Purdue for all research activities related to the use of Fourier transform infrared microspectroscopy to identify and characterize cell-wall mutants in maize and Arabidopsis.  In addition, I have worked on just about all aspects of the lab's activities. My most recent endeavor is to characterize the expression of a gene encoding a unique cell-wall protein that binds to the fibrin-binding domain of human fibronectin (Fn). A former graduate student, Dr. Sarah Wyatt (Assistant Professor, Ohio University) developed what she termed a "Far-Western" blot to identify this protein. Proteins electroblotted after SDS-PAGE are incubated with human (Fn), and the plant proteins able to bind to Fn are subsequently detected with an anti-Fn antibody. A 46 kDa polypeptide associated with the cell-wall and a fainter 97 kDa polypeptide were detected. When fibronectin is cut into four distinct fragments, only the N-terminus fragment bound to the 46 kDa plant FnBP. The same strategy was used to select a cloned cDNA from a plaque-lift. However, the sequence represented only about one-half of the expected transcript. I found that the appearance of an Arabidopsis 46 kDa FnBP is induced by NaCl when added to the medium of a cell suspension culture. The single-copy Arabidopsis gene turns out to encode 97 kDa polypeptide: the FnBP function is in the C-terminus half, whereas the N-terminus half contains a putative protein kinase. Expression is constitutive, but only the 46 kDa fragment appears when NaCl is added to the medium.

Dr. Bryan Penning Plant cell wall formation is a complex process involving a large number of genes that form, assemble, and disassemble cell wall components, such as polysaccharides, cell wall associated proteins, and aromatic substances, such as lignin and hydroxycinnamic acids.  Also, cell wall composition differs greatly between commelinoid monocots, such as Oryza sativa (rice) and Zea mays (maize), and all dicots and other non-gramineous monocots.  My main focus in the lab involves database mining for genes in O. sativa and Z. mays with homology to A. thaliana cell-wall related proteins.  These genes are being organized into unrooted dendograms and will be placed on our NSF-sponsored website: http://cellwall.genomics.purdue.edu/ following the format of the A. thaliana information previously posted to the website.  I am also developing phylogenetic comparisons between cell wall related proteins of these three plant species using protein sequence alignment.  As an additional project I will be working to clone cell wall mutant genes in A. thaliana using map-based and recombinant inbred approaches.

Dr. Catherine Rayon After completion of my post-doctoral work here at Purdue and at the CNRS-Toulouse in France, I am currently an Assistant Professor at Université de Picardie-Jules Verne in Amiens, France.  However, I continue my work during part of the year as a Visiting Scientist at Purdue on the heterologous expression of full-length and catalytic portions of cellulose synthase and cellulose synthase-like genes and convenient purification of recombinant proteins. Together with the Jeff Bolyn and members of the Markey Center for Structural Biology at Purdue, we are attempting to crystallize these recombinant polypeptides to obtain 3-dimensional structural information about the principal catalytic domains of cellulose synthase.

Click here to view information on our former lab workers.

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Assistantships and Positions

Please contact me directly for information on assistantships and openings in my program. Follow these links for general information on graduate programs or employment announcements.

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Selected Publications

Yong, W., N.C. Carpita, B. Link, X. Li, W-D. Reiter, R. O’Malley, A.B. Bleeker, S.E Patterson, J. Tewari, M.C. McCann, C. Staiger, C.T. Hunter, C.-A. Lu, K.E. Koch, D.R. McCarty, S.R. Thomas, W. Vermerris. 2005. Genomics of plant cell wall biogenesis. Planta  221, 747-751 - Click here for full publication (pdf file)

Pena, M.J.and N.C. Carpita. 2004. Loss of Highly Branched Arabinans and Debranching of Rhamnogalacturonan I Accompany loss of Firm Texture and Cell Separation during Prolonged Storage of Apple. Plant Physiology. 135, 1305-1313 - Click here for full publication (pdf file)

Pena, M.J., P. Peter, M. Madson, A.C. Smith, N.C. Carpita. 2004. The Galactose Residues of Xyloglucan Are Essential to maintain Mechanical Strengh of the Primary Cell Walls in Arabidopsis during Growth. Plant Physiology. 134, 443-451 - Click here for full publication (pdf file)

Urbanowicz, B. R., C. Rayon, N. C. Carpita.  2004. Topology of the maize mixed-linkage (1→3),(1→4)-ß-D-glucan synthase at the Golgi membrane.  Plant Physiol. 134, 758-768 - Click here for full publication (pdf file)

Peña, M. J., P. Ryden, M. Madson, A. Smith, W-D. Reiter, N. C. Carpita.  2004.  Galactosylation of xyloglucans is essential for maintenance of cell wall tensile strength during cell growth in plants.  Plant Physiol.134, 443–451.

Buckeridge, M. S., C. Rayon, B. Urbanowicz, M. A. S. Tine, N. C. Carpita.  2004. Mixed linkage (1→3),(1→4)-ß-D-glucans of grasses.  Cereal Chem.81, 115-127 - Click here for full publication (pdf file)

Madson, M., C. Dunand, X. Li, R. Verma, G.F. Vanzin, J. Caplan, D.A. Shoue, N.C. Capita, W-D. Reiter.  2003. The MUR3 Gene of Arabidopsis Encodes a Xyloglucan Galactosyltransferase That Is Evolutionarily Related to Animal Exostosins. The Plant Cell. 15, 1662-1670 - Click here for full publication (pdf file)

Zhu, Y., J. Nam, N. C. Carpita, A. G. Matthysse, and S. B. Gelvin.  2003.  Agrobacterium-mediated root transformation is inhibited by mutation of an Arabidopsis cellulose synthase-like gene.  Plant Physiol.133, 1000-1010.

Madson, M., C. Dunand, R. Verma, G. F. Vanzin, J. Caplan, X. Li, D. A., Shoue, N. C. Carpita, W-D. Reiter.  2003. Xyloglucan galactosyltransferase, a plant enzyme in cell wall biogenesis homologous to animal exostosins.  Plant Cell 15, 1662–1670.

Lao, N. T., D. Long, S. Kiang, G. Coupland, D. A. Shoue, N. C. Carpita, T. A. Kavanagh.  2003.  Mutation of a family 8 glycosyltransferase gene alters cell wall carbohydrate composition and causes a humidity-sensitive semi-sterile dwarf phenotype in Arabidopsis.  Plant Mol. Biol. 53, 687-701 - Click here for full publication (pdf file)

Vanzin, G. F., M. Madson, N. C. Carpita, N. V. Raikhel, K. Keegstra, W-D. Reiter.  2002.  The mur2 mutant of Arabidopsis thaliana lacks fucosylated xyloglucan because of a lesion in fucosyltransferase AtFUT1.  Proc. Natl. Acad. Sci. USA99, 3340-3345 - Click here for full publication (pdf file)

Carpita, N. C., and M. C. McCann.  2002.  The functions of cell wall polysaccharides in composition and architecture revealed through mutations.  Plant Soil 274, 71-80.

Carpita, N. C., M. Defernez, K. Findlay, B. Wells, D. A. Shoue, G. Catchpole, R. H. Wilson, and M. C. McCann.  2001. Cell wall architecture of the elongating maize coleoptile.  Plant Physiol127, 551-565.

Penfield, S., R. C. Meissner, D. A. Shoue, N. C. Carpita, and M. W. Bevan.  2001. MYB61 is required for mucilage deposition and extrusion in the Arabidopsis seed coat.  Plant Cell13, 2777-2791. [plus cover]

Carpita, N., M. Tierney, and M. Campbell.  2001. Molecular biology of the plant cell wall:  Searching for the genes that define structure, architecture and wall dynamics.  Plant Mol. Biol. 47, 1-5.

Vergara, C. E., N. C. Carpita.  2001.  ß-D-Glycan synthases and the CesA gene family:  Lessons to be learned from themixed-linkage (1→3),(1→4)ß-D-glucan synthase.Plant Mol. Biol.47, 145-160.

Schindelman, G., A. Morikami, J. Jung, T. I. Baskin, N. C. Carpita, M. C. McCann, P. N. Benfey.  2001.  The COBRA gene encodes a putative glycosylphosphatidyl-inositol anchored protein, which is polarly localized and necessary for oriented cell expansion in Arabidopsis.  Genes Dev. 15, 1115-1127.

Buckeridge, M.S., C.E. Vergara, N.C. Carpita. 1999. The Mechanism of Synthesis of a Mixed-Linkage (1→3),(1→4) ß-D-Glucan in Maize.  Evidence for Multiple Sites of Glucosyl Transfer in the Synthase Complex. Plant Physiology. 120, 1105-1116 - Click here for full publication (pdf file)

Gibeaut, D.M., and N.C. Carpita. 1993. Synthesis of (1→3), (1→4)-ß-D-glucan in the Golgi apparatus of maize coleoptiles. Proc. Natl. Acad. Sci USA90, 3850-3854 - Click here for full publication (pdf file)

Book Chapters and Reviews

Carpita, N. C., and M. C. McCann.  2000.  Chapter 2 “The Cell Wall” In: Biochemistry and Molecular Biology of Plants (B. B. Buchanan, W. Gruissem, R. Jones, eds), American Society Plant Physiologists, Rockville, MD.

Carpita, N.C.  1996.  Structure and biogenesis of the cell walls of grasses.  Annu. Rev. Plant Physiol. Plant Molec. Biol.47, 445-476

Carpita, N. C., and D. M. Gibeaut.  1993.  Structural models of primary cell walls in flowering plants: Consistency of molecular structure with the physical properties of the walls during growth.  Plant J.3, 1-30.