Photo:
Elaine Simons |
Research | Teaching | Team | Publications
e-mail:lsamuels@mail.ubc.ca
office phone: (604)822-3554
other phone: (604) 822-5469
lab phone: (604) 822-5223
Head of Deptartment
B.Sc. (1984), McGill Univ.;
Ph.D. Botany (1989) UBC;
Postdoctoral Fellow, (1993-95), Univ. Colorado;
Research Associate, (1996-2000) UBC.
Lab Website: http://samuelslab.blogspot.com
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Research Interests:
My area of interest is plant cell biology, especially the
biosynthesis and secretion of the plant cell wall.
The study of the extracellular matrix in plants presents
special challenges for cell biologists due to the tight
association of the wall with the plasma membrane and the
plants' turgor-driven mode of growth. The cell wall limits
the reagents and probes that can be applied to the plant
cell and removal of the cell wall requires altering the
normal osmotic environment of the cell. For these reasons,
I use specialized freezing techniques (cryofixation) such
as high pressure freezing, which can immobilize cell water
intact and allow detailed electron microscopic examination
of the cell.
1. Cytokinesis
In the past, I have studied how dividing plant cells produce
the new cell wall following mitosis. Using cryofixation,
as well as antibody probes, a new view of the developing
cell plate was elucidated in tobacco cells grown in culture.
More recently, we have studied this process in the inner
bark (secondary vascular cambium) of pine and found the
same delicate membrane structures as in tobacco.
TEM of High pressure frozen/Freeze substituted Pine cambium
showing new cell wall forming (cell plate).
Rensing et al. (2002).

2. Xylem development and lignification
Recently my research interests have expanded to focus on
non-polysaccharide components of the cell wall such as lignin
and wax. Lignin is a polymer made up of units called monolignols,
which link together to give plant cell walls strength. The
monolignols must be exported from the cytoplasm to specific
sites in the cell wall. Using developing secondary xylem
(wood) of Pinus contorta var. latifolia (Lodgepole Pine)
as an experimental system, We are exploring how some of
the enzymes of monolignol biosynthesis are arranged in the
cell and what is the cellular mechanism of monolignol export.
Typical cell structures observed in developing xylem from
Pinus contorta var. latifolia. Cells were prepared by cryofixation
and TEM. Both membrane and cytoskeleton structures are preserved
in these cells which are actively secreting the thick secondary
cell wall.

Unusual Golgi structures are characteristic of differentiating
Pinus secondary xylem (wood). Cells were prepared by cryofixation
and TEM. We are presently using cryo-fixation and autoradiography
to study the distribution of phenylpropanoids in these cells.

3. Epicuticular wax secretion in Arabidopsis
cryoSEM of wax on the surface of an Arabidopsis stem.

Wax is an essential feature of aerial portions of plants,
as it limits water loss and protects from environmental
and insect stresses. The epidermal cells of the stem synthesize
and secrete this hydrophobic product. It is not known if
secretion is Golgi-mediated or how the hydrophobic product
is targeted to the extracellular environment. In Arabidopsis
thaliana, mutants have been identified which are impaired
in stem wax productions. Studying these mutants using a
combination of cryofixation/electron microscopy, light microscopy,
gas chromatography, and freeze fracture, is giving us new
insights on the mechanism of wax secretion.
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Courses
Taught (2008-2009):
Biology 200 - Cell Biology I
Biology 210 - Vascular Plants
Biology 535 - Teaching and Learning in the Life Sciences
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Research
Team:
Minako Kaneda (Ph.D. student)
Robin Young (Graduate Student)
Allan DeBono (Ph.D. student)
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Publications:
McFarlane, H.E., Shin, J.J., Bird, D.A., and Samuels, A.L. 2010. Arabidopsis ABCG transporters, which are required for export of diverse cuticular lipids, dimerize in different combinations. Plant Cell 22: 3066-3075. [view abstract]
Quilichini, T.D., Friedmann, M.C., Samuels, A.L., and Douglas, C.J. 2010. ATP-binding cassette transporter G26 (ABCG26) is required for male fertility and pollen exine formation in Arabidopsis. Plant Physiology 154: 678-690. [view abstract]
Kaneda, M., Rensing, K., and Samuels, A.L. 2010. Secondary cell wall deposition in developing secondary xylem of poplar. Journal of Integrative Plant Biology 52: 234-243. [view abstract]
Kunst, L. and Samuels, A.L. 2009. Plant cuticles shine: advances in wax biosynthesis and export. Current Opinion in Plant Biology 12: 721-727. [view abstract]
DeBono, A., Yeats, T.H., Rose, J.K.C., Bird, D., Jetter, R., Kunst, L., and Samuels, A.L. 2009. Arabidopsis LTPG is a glycosylphosphatidylinositol-anchored lipid transfer protein required for export of lipids to the plant surface. The Plant Cell 21: 1230-1238. [view abstract] [Faculty of 1000]
M. Kaneda,
K.H. Rensing, J.C.T. Wong, B. Banno, S.D. Mansfield, A.L. Samuels. (2008)
Tracking Monolignols During Wood Development in Pinus contorta
var. latifolia. Plant Physiology First published on June 11,
2008; 10.1104/pp.108.121533.
Robin E. Young, Heather E. McFarlane, Michael G. Hahn,
Tamara L. Western, George W. Haughn, A. Lacey Samuels. (2008)
Analysis of the Golgi apparatus in Arabidopsis seed coat
cells during polarized secretion of pectin-rich mucilage.
Plant Cell, First published on June 3, 2008; 10.1105/tpc.108.058842.
http://www.plantcell.org/cgi/content/short/tpc.108.058842?keytype=ref&ijkey=Ox7pzryqDr1MRXN
P.J. Verrier,
D. Bird, B. Burla, E. Dassa, C. Forestier, M. Geisler, M. Klein, Ü.
Kolukisaoglu, Y. Lee, E. Martinoia, A. Murphy, P.A. Rea, L. Samuels, B.
Schulz, E.J. Spalding, K. Yazaki and F.L. Theodoulou (2008) Plant ABC
proteins – a unified nomenclature and updated inventory. Trends
in Plant Science 13: 151-159.
Samuels A.L., L. Kunst, R. Jetter (2008) Sealing plant
surfaces: cuticular wax formation by epidermal cells. Annual
Review of Plant Biology. Vol. 59: 683-70.
http://arjournals.annualreviews.org/eprint/85MD3UMSPqz2nNXcFuaR/full/10.1146/annurev.arplant.59.103006.093219
This Annual Review is linked to a video starring Botany
grad students, Allan DeBono, Patricia Lam and Miao Wen,
describing the use of Arabidopsis mutants to study the plant
cuticle. JOVE
video
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