Comparative glycan profiling of Ceratopteris richardii 'C-Fern' gametophytes and sporophytes links cell-wall composition to functional specialization.
OBJECTIVE
Innovations in vegetative and reproductive characters were key factors in the evolutionary history of land plants and most of these transformations, including dramatic changes in life cycle structure and strategy, necessarily involved cell-wall modifications. To provide more insight into the role of cell walls in effecting changes in plant structure and function, and in particular their role in the generation of vascularization, an antibody-based approach was implemented to compare the presence and distribution of cell-wall glycan epitopes between (free-living) gametophytes and sporophytes of Ceratopteris richardii 'C-Fern', a widely used model system for ferns.


METHODS
Microarrays of sequential diamino-cyclohexane-tetraacetic acid (CDTA) and NaOH extractions of gametophytes, spores and different organs of 'C-Fern' sporophytes were probed with glycan-directed monoclonal antibodies. The same probes were employed to investigate the tissue- and cell-specific distribution of glycan epitopes.


RESULTS
While monoclonal antibodies against pectic homogalacturonan, mannan and xyloglucan widely labelled gametophytic and sporophytic tissues, xylans were only detected in secondary cell walls of the sporophyte. The LM5 pectic galactan epitope was restricted to sporophytic phloem tissue. Rhizoids and root hairs showed similarities in arabinogalactan protein (AGP) and xyloglucan epitope distribution patterns.


CONCLUSIONS
The differences and similarities in glycan cell-wall composition between 'C-Fern' gametophytes and sporophytes indicate that the molecular design of cell walls reflects functional specialization rather than genetic origin. Glycan epitopes that were not detected in gametophytes were associated with cell walls of specialized tissues in the sporophyte.
Research Group Pteridology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium sharon.eeckhout@ugent.be.
Sharon
S
Eeckhout
Research Group Pteridology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium Botany and Plant Science and The Ryan Institute for Environmental, Marine and Energy Research, School of Natural Sciences, National University of Ireland Galway, University Road, Galway, Ireland.
Olivier
O
Leroux
Department of Plant Biology and Biochemistry, Faculty of Life Sciences, University of Copenhagen, Buelowsvej 17-1870 Frederiksberg, Denmark.
William G T
WG
Willats
Botany and Plant Science and The Ryan Institute for Environmental, Marine and Energy Research, School of Natural Sciences, National University of Ireland Galway, University Road, Galway, Ireland.
Zoë A
ZA
Popper
Research Group Pteridology, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Ronald L L
RL
Viane
D000911:Antibodies, Monoclonal; D005075:Biological Evolution; D002473:Cell Wall / Q000378:metabolism*; D055993:Germ Cells, Plant / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D005936:Glucans / Q000378:metabolism; D007150:Immunohistochemistry; D046228:Microarray Analysis; D009088:Mucoproteins / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism*; D029625:Pteridaceae / Q000166:cytology / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D013170:Spores / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D014990:Xylans / Q000378:metabolism
D000911:Antibodies, Monoclonal; D005936:Glucans; D009088:Mucoproteins; D010940:Plant Proteins; D011134:Polysaccharides; D014990:Xylans; C006619:arabinogalactan proteins; C029353:xyloglucan
Ceratopteris richardii ‘C-Fern’; gametophyte; glycan microarray; immunocytochemistry; monilophytes; plant cell wall; pteridophyta; sporophyte