George Haughn

Faculty Profile

Faculty Profile

Photo by: Elaine Simons Lane
Professor

Plant Developmental Genetics. Molecular genetics of seed coat development in Arabidopsis thaliana.

B.Sc. Biology (1978), Dalhousie Univ.;
Ph.D. Genetics (1985) Cornell Univ.;
Postdoctoral Fellow (1985-1987) MSU-DOE Plant Research Laboratory;
Assistant Professor of Biology (1987-1990), Univ. Saskatchewan;
Associate Professor of Biology, (1990-1993), Univ. Saskatchewan; 
Associate Professor of Botany, (1993-2000), Univ. of British Columbia;

Contact Information

Room 2239, Biological Sciences Building
604-822-9089
Room 2234, Biological Sciences Building
604-822-2437
604-822-6089
george.haughn@ubc.ca

Research Interests

My laboratory uses molecular genetics and the seed coat epidermal cell of Arabidopsis thaliana as a model to investigate plant cell wall biosynthesis, structure and function.  We also run a TILLING service described below.

 

1. Mechanisms underlying cell differentiation. The seed coat is a specialized tissue derived from ovule integuments. In some species, including Arabidopsis thaliana, large quantities of polysaccharide mucilage (pectin) and secondary cell wall are produced by seed coat epidermal cells at specific times during differentiation. Because these modifications are not required for viability, the Arabidopsis seed coat epidermal cells represent a unique dispensable tissue that can be used to identify genes involved in complex polysaccharide biosynthesis and secretion (Haughn and Chaudhury, 2005; Arsovski et al., 2010; Haughn and Western, 2012), important processes about which relatively little is known. As a first step to develop this unique model system we investigated the structure and differentiation of Arabidopsis seed coat secretory cells including the synthesis, secretion and extrusion of mucilage (Western et al., 2000) and isolated a number of mutants defective in the differentiation, synthesis and extrusion of mucilage (Western et al., 2001). Our characterization of these and other mutants and cloning of the mutated genes  has identified a number of proteins playing key roles in cell wall biology including biosynthesis (MUM4; Western et al., 2004) modification (MUM2, BXL1, FLY1; Dean et al., 2007, Arsovski et al., 2009, Voiniciuc et al., 2013) secretion (Young et al., 2008; McFarlane et al., 2013) and regulation (Western et al., 2004; Huang et al., 2011) of mucilage pectins and synthesis of cellulose in mucilage (CESA5; Mendu et al., 2011) and for the secondary cell wall columella (CESA2, CESA5, CESA9; Stork et al., 2009, Mendu et al., 2011). We have also developed some useful information and tools for the study of the seed coat including a microarray analysis (Dean et al., 2011) and a seed coat specific promoter (Esfandiari., 2013).  Finally, we have discovered a metabolic link between the production of mucilage and the synthesis of storage oil in the embryo (Shi et al., 2012) Current  projects include identification of additional seed coat specific promoters, genetic modifier analysis of MUM2, investigation of mechanisms controlling secretion expression, proteomic analysis of mucilage and the engineering of cell wall carbohydrates in the mucilage pocket. 

 

2. TILLING. TILLING (Targeted Induced Local Lesions in Genomes) is a powerful technique that can identify a series of allelic mutations or SNPs in a target gene by heteroduplex analysis (Till BJ, et al. 2003, Genome Res. 13:524-530; Gilchrist and Haughn, 2005; Gilchrist and Haughn, 2010). It can be adapted for use in a high-throughput facility, and has been successfully applied to many plants and animals. Beginning in 2002 we established a TILLING facility, CAN-TILL (http://www.botany.ubc.ca/can-till/) at UBC. We have developed a TILLING service in Canada that will be able to identify mutations in genes from a wide variety of different organisms. To date we have successfully TILLED in Arabidopsis thaliana, Caenorhabditis elegans (Gilchrist et al., 2006B), Brassica oleracea (Himelblau et al., 2009) and Brassica napus (Gilchrist et al., 2013). We have also used TILLING to look at natural variation in Populus trichocarpa (known as EcoTILLING; Gilchrist et al., 2006A). We are always in search of partners to develop TILLING populations in other organisms.

Teaching

Biology 234 - Fundamentals of Genetics
Biology 433 - Plant Genetics

Team Members

Erin Gilchrist (Research Associate)
Gillian Dean (Research Associate)
Allen Tsai (Postdoctoral Fellow)
Tadashi Kunieda (Postdoctoral Fellow)
Yi-chen Lee (Graduate Student, PhD)
Kresimir Sola (Graduate Student, PhD)
Robert McGee (Graduate Student, PhD)

Selected Publications

Griffiths, J.S., A. Y.-L. Tsai, H. Xue, , C. Voiniciuc, K. Šola, G.J. Seifert, S.D. Mansfield and G.W. Haughn. 2014. SOS5 mediates Arabidopsis seed coat mucilage adherence and organization through pectins. Plant Physiol. 165: 991-1004.

Gilchrist E.J., C.H.D. Sidebottom, C.S. Koh, T. MacInnes,
A.G. Sharpe, G.W. Haughn. 2013. A Mutant Brassica napus (Canola) Population for the Identification of New Genetic Diversity via TILLING and Next Generation Sequencing. PLoS One. 8: e84303.

Voiniciuc C., G.H. Dean, J.S. Griffiths, K. Kirchsteiger, Y-T. Hwang, A. Gillett, G. Dow, T.L. Western, M. Estelle, and G.W. Haughn. 2013. FLYING SAUCER1 Is a Transmembrane RING E3 Ubiquitin Ligase That Regulates the Degree of Pectin Methylesterification in Arabidopsis Seed Mucilage. Plant Cell 25: 944-959 (cover article).

Esfandiari E., Z. Jin, A. Abdeen, J.S. Griffiths, T.L. Western and G.W. Haughn. 2013. Identification and analysis of an outer-seed-coat-specific promoter from Arabidopsis thaliana. Plant Mol. Biol. 81:93–104.

Haughn G.W. and T.L. Western. 2012. Arabidopsis seed coat mucilage is a specialized cell wall that can be used as a model for genetic analysis of plant cell wall structure and function. Frontiers Plant Sci. 3: 64.

Dean G., Y. Cao, D Xiang, N.J. Provart, L. Ramsay, A. Ahad, R. White, G. Selvaraj, R. Datla and G. Haughn. 2011. Analysis of gene expression patterns during seed coat development in Arabidopsis. Mol. Plant 4: 1074-1091.

Huang J., D. DeBowle2, E. Esfandiari1, G. Dean, N.C. Carpita and G.W. Haughn. 2011. The Arabidopsis Transcription Factor LUH/MUM1 Is Required for Extrusion of Seed Coat Mucilage. Plant Physiol: 156: 491-502.

Stork J. , D. Harris , J. Griffiths , B. Williams , F. Beisson , Y. Li-Beisson , V. Mendu , G. Haughn and S. DeBolt. 2010.  CELLULOSE SYNTHASE9 serves a non-redundant role in secondary cell wall synthesis in Arabidopsis epidermal testa cells.  Plant Physiol. 153: 580–589.

Arsovski, A.A., G.W. Haughn and T.L. Western. 2010. Seed coat mucilage cells of Arabidopsis thaliana as a model for plant cell wall research. Plant Signaling & Behavior  5: 796 - 801.

Gilchrist, E. and G.W. Haughn. 2010. Reverse genetics techniques: engineering loss and gain of gene function in plants. Briefings in Functional Genomics and Proteomics 9: 103-110.

Arsovski A.A., T.M. Popma, G.W. Haughn, N.C. Carpita, M.C. McCann and T.L. Western. 2009. AtBXL1 encodes a bifunctional β-D-xylosidase/α-L-arabinofuranosidase required for pectic arabinan modification in Arabidopsis thaliana mucilage secretory cells.  Plant Physiol. 150: 1219-1234.

Himelblau E., E.J. Gilchrist, K. Buono, C. Bizzell, L  Mentzer., R. Vogelzang, T. Osborn, R.M. Amasino, I.A. Parkin, G.W. Haughn2009. Forward and reverse genetics of rapid-cycling Brassica oleracea. Theor. Appl. Genet. 118: 953-961.

Young, RE, HE McFarlane, MG Hahn, TL Western, GW Haughn, and AL Samuels. (2008). Analysis of the Golgi Apparatus in Arabidopsis Seed Coat Cells during Polarized Secretion of Pectin-Rich Mucilage. Plant Cell 20: 1623–1638.

Dean G.H., H. Zheng, J. Tewari, J. Huang, D. S. Young, Y.T. Hwang, T. L. Western, N.C. Carpita, M.C. McCann, S.D. Mansfield, and G. W. Haughn. (2007). The Arabidopsis MUM2 Gene Encodes a ß-Galactosidase Required for the Production of Seed Coat Mucilage with Correct Hydration Properties. Plant Cell 19: 4007-4021.

Gilchrist EJ, NJ O’Neil, AM Rose, MC Zetka and GW Haughn. (2006B). TILLING is an effective reversegenetics technique for Caenorhabditis elegans. BMC Genomics 7:262.

Gilchrist, E. J., G.W. Haughn, C.C. Ying, S. P. Otto, J. Zhuang, D. Cheung, B. Hamberger, F. Aboutorabi, T. Kalynyak, L. Johnson, J. Bohlmann, B.E. Ellis, C.J. Douglas and Q.C.B. Cronk, (2006A). Use of Ecotilling as an efficient SNP discovery tool to survey genetic variation in wild populations of Populus trichocarpa. Molecular Ecology 15: 1365-1376.

Haughn G. and A. Chaudhury. (2005). All Dressed Up With Nowhere To Go: Genetic Analysis of Seed Coat Development in Arabidopsis. Trends in Plant Science 10: 472-477.

Gilchrist, E. J. and G.W. Haughn. (2005). TILLING without a plough: a new method with applications for reverse genetics. Current Opinion in Plant Biology 8:211–215.

Western T.L., 2, D.S. Young, G.H. Dean, W.L. Tan, A.L. Samuels, and G.W. Haughn (2004) MUCILAGE-MODIFIED4 Encodes a Putative Pectin Biosynthetic Enzyme Developmentally Regulated by APETALA2, TRANSPARENT TESTA GLABRA1, and GLABRA2 in the Arabidopsis Seed Coat. Plant Physiology, 134: 296–306

Western, T.L., J. Burn, W. L. Tan, D. Skinner, L. M. McCaffrey, B. Moffatt and G. W. Haughn. (2001) Isolation and characterization of mutants defective in seed coat mucilage secretory cell development in Arabidopsis . Plant Physiology 127: 998-1011.

Western, TL, DJ Skinner & GW Haughn. (2000). Differentiation of mucilage secretory cells of the Arabidopsis thaliana seed coat. Plant Physiology 122: 345-355.