Table Of ContentCell and Developmental Biology
of Arabinogalactan-Proteins
Cell and Developmental Biology
of Arabinogalactan-Proteins
Edited by
Eugene A. Nothnagel
University of California
Riverside, California
Antony Bacic
and
Adrienne E. Clarke
University of Melbourne
Parkville, Victoria, Australia
Springer Science+Business Media, LLC
http://avaxhome.ws/blogs/ChrisRedfield
Library of Congress Cataloging-in-Publication Data
CeH and developmental biology of arabinogalactan-proteins/edited by Eugene A.
Nothnagel, Antony Baeic, and Adrienne E. Clarke.
p. cm.
"Proceedings of the Twentieth Symposium in Plant Physiology, held lanuary 21-23, 1999, at
the University of California, Riverside" - T.p. verso.
Includes bibliographical references.
ISBN 978-1-4613-6888-5 ISBN 978-1-4615-4207-0 (eBook)
DOI 10.1007/978-1-4615-4207-0
1. Arabinogalactan-Congresses. 1. Nothnagel, Eugene A. II. Baeic, A. (Antony) III.
Clarke, A. E. (Adrienne Elizabeth) IV. Symposium in Plant Physiology (20th: 1999:
University of California, Riverside)
QK898.A67 C46 2000
572'.68-dc21
00-058755
Proceedings of the Twentieth Symposium in Plant Physiology, held January 21-23, 1999, at the University of
California, Riverside
ISBN 978-1-4613-6888-5
© 2000 Springer Science+Business Media New York
Originally published by Kluwer Academic / Plenum Publishers, New York in 2000
Softcover reprint of the hardcover 1s t edition 2000
AII rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form
or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise,
without writlen permis sion from the Publisher
Preface
This volume captures a sense of the impact that the study of
arabinogalactan-proteins (AGPs) is having in plant physiology. We have
moved from a very diffuse set ofobservations on the distribution ofAGPs
in plants to apoint where we can see some threads ofresearch direction and
some critical issues to be resolved. In this context it is interesting to recall
that the reviewer of a proposal seeking funding for the meeting held at the
University of California at Riverside in January, 1999, noted that "it is
difficult to get an idea ofwhere the field is headed other than you can find
AGPs wherever you look!" It is true that AGPs are ubiquitous. We are
now seeing, however, that different AGPs may have different tissue and
cellular locations and that some appear and disappear during development.
With this distribution and developmental control of AGPs, it is not
unreasonable to consider that they may well have a range of functions.
Indeed, some AGPs may be critical to survival, and this could be one
reason why many people have observed a very low frequency of plants
resulting from antisense experiments using AGP polypeptide backbone
genes. In response to the reviewer's comment that it is difficult to get an
idea ofwhere the field is headed, one approach is to consider the blockages
to further understanding ofboth the form and function of AGPs and their
reciprocal relationships.
FORM OF ARABINOGALACTAN-PROTEINS
The fact that there are so many closely related but not identical AGPs
leads to the questions of "What is an AGP?" and "When does one AGP
differ from another?"
v
Preface
VI
In this context, both the structure ofthe polypeptide backbones and the
glycosyl constituents need to be understood. Features of the polypeptide
backbones needing improved understanding include their domain structure,
their diversity, whether they are glycosylphosphatidylinositol-anchored or
not, and whether the genes encoding the polypeptide backbones include
introns ornot. Some ofthe questions regarding the carbohydrate chains are
"How many types of chains?", "Where are the points of glycosylation?",
"What parts ofthe polypeptide backbone are covered or exposed?", "What
is the diversity ofthe carbohydrate sequences?", "What is the overall shape
ofthe molecule?", and "What parts ofthe polypeptide and the carbohydrate
side chains might be accessible for binding to othermolecules?"
POSSIBLE FUNCTIONS OF ARABINOGALACTAN-PROTEINS
Many different functions have been implied from observations of the
involvement ofAGPs in such diverse physiological effects as programmed
cell death, cell division, arrest of growth (reversible), oxidative
bursts/wounding, somatic embryogenesis, pollen tube growth, chilling
protection, microsporogenesis, growth suppression, and xylem formation.
Observations on many ofthese involvements ofAGPs are detailed in this
volume, but at present, no one function of a single AGP is understood in
detail.
In furthering our understanding of both the form and the function of
AGPs, it became clear during the meeting that there are several critical
issues to be addressed -
(i) The specificity ofthe Yariv reagent. It is important to establish the
exact identities of the molecules to which the Yariv reagent binds.
Certainly the reagent precipitates AGPs from tissue extracts. It would
be valuable, however, to know the key features of both the
polysaccharide and the polypeptide components which are required for
binding to the Yariv reagent.
(ii) Sequence analysis of glycosyl chains. Understanding the precise
structure and arrangement of the glycosyl chains is critical to our
ultimate understanding ofboth the form and the function ofAGPs. A
current roadblock is the lack ofroutine and facile methods for isolating
the glycosyl chains and establishing the monosaccharide com
ponents, linkages, and overall sequence. Commercial availability of
glycosidases with defined specificities for the linkages which
commonly occur in AGPs would be extremely helpful. The panel of
monoclonal antibodies currently available is a useful tool set, although
this usefulness is limited by lack of detailed specificity studies for
many ofthese antibodies.
Preface VB
(iii) Availability of defined oligosaccharide fragments as reagents. The
fact that the specificity ofthe antibodies has been defined in only a few
cases reflects the lack ofdefined oligosaccharides that can be used as
reagents. Commercial availability ofoligosaccharides ofgalactose and
arabinose in the relevant linkages, for example, would enable rapid
progress to be made in applying immunocytochemical techniques to
the cellular location and function ofdifferent AGPs.
(iv) Biosynthesis of AGPs. Understanding how the various chains are
formed and at what stage the glycosylation of the polypeptide
backbone occurs will give us insight into the groups of AGPs with
similarbut distinct structural features.
(v) The number ofAGPs within a particular plant tissue. We do not yet
have a sense ofthe complete range ofAGPs in plant tissues. There are
salt-extractable, non-salt extractable, membrane-bound, and non
membrane-bound AGPs, but the complete range for any particular
tissue or cell type and the differences between the members of this
range are still not defined.
(vi) Arabidopsis mutants. The range of Arabidopsis mutants available
provides an invaluable experimental tool for understanding the
relationship between form and function of AGPs. Nonetheless, the
precise details ofthe chemistry ofthe different AGPs will be required
to get an understanding of the mutations in these complex
proteoglycans.
A related topic discussed during the meeting was the potential
commercial use ofAGPs. There is evidence supporting the idea that they
can be used to induce immunostimulation in animals, and there may be
other medicinal uses. Industrial uses rely on their functionality as
emulsifiers, for example, in the food and cosmetic industries. There are
many opportunities for applying current knowledge of the chemistry of
AGPs to these industrial applications, many of which are presently based
on empirical observations.
All in all, we anticipate that by the time the next meeting is held, we will
have created a much broader knowledge base of both the form and the
function ofAGPs. We can look forward to a further understanding ofhow
the design ofthese complex and varied proteoglycans is adapted for their
seemingly myriad functions.
Adrienne E. Clarke
University ofMelbourne
Acknowledgements
As editors ofthis volume, we wish to thank each ofthe authors for their
scholarly contribution and for their cooperation and patience as this volume
was assembled. Prominent acknowledgement and our enormous gratitude
go to Nancy Day and Laura Heraty ofthe Department ofBotany and Plant
Sciences at Riverside for their editorial assistance and many, many hours of
word processing to produce the camera-ready copy ofthis volume. We also
thank MaryAnn McCarra, our editor at Kluwer Academic/Plenum
Publishers.
As organizers of the 20th Symposium in Plant Physiology at the
University of California, Riverside, upon which this volume is based, we
prominently acknowledge Symposium Coordinators Cindi McKernan and
Susana Aparicio, whose expertise and tireless attention to every detail in
Riverside were greatly appreciated by both the organizers and the attendees
at the symposium. We similarly thank Joanne Noble for her coordination
and assistance in Melbourne. Our thanks also go to many other members of
the Department of Botany and Plant Sciences including Cherie Cooksey,
Ann Montejano, and Susan Miller, who handled finances, accounting, and
many other essential functions; Van Stout and Lee Gross, who supplied the
display boards for the poster session; and Rick Miranda, Watt Pattanagul,
Kristen Lennon, Jean-Claude Mollet, David Puthoff, Donna Dubay, and
Ricardo Cesped, who provided ground transportation and other assistance.
We are sincerely grateful to the following governmental agencies,
industrial corporations, and University of California programs and
administrators for their financial contributions to the support of the
sympoSIum:
IX
x Acknowledgements
United States Department ofAgriculture
(Award 98-35304-6921from thePlant Growth andDevelopmentProgram)
National Science Foundation
(Award 9808309from the Integrative PlantBiologyProgram)
PioneerHi-Bred International, Inc.
Bestfoods Baking Company
GLYKO, Inc.
Dionex Corporation
Biosupplies AustraliaPty. Ltd.
University ofCaliforniaBioSTAR Project
Michael Clegg, Dean, College ofNatural and Agricultural Sciences, UCR
Elizabeth Lord, Chair, Department ofBotany and Plant Sciences, UCR
Neither the symposium nor this volume would have beenpossible without
the financial support ofthese sponsors.
A. E. Clarke E. A. Nothnagel A. Bacic
UniversityofMelbourne UniversityofCalifornia, Riverside UniversityofMelbourne
Contents
Abbreviations xvii
SECTION 1: STRUCTURE AND BIOSYNTHESIS OF
ARABINOGALACTAN-PROTEINS
1. ABriefHistory ofArabinogalactan-Proteins 1
B. A. Stone andK. Valenta
2. Structural Classes ofArabinogalactan-Proteins 11
A. Bacic, G. Currie, P. Gilson, S.-L. Mau, D. Oxley, C. Schultz, J.
Sommer-Knudsen, and A. E. Clarke
3. MolecularAnalysis ofGenes EncodingArabinogalactan-Proteins 25
C. Reuzeau, L. Snogerup, and P. Kjellbom
4. The C-Terminal PAC Domain of a Secreted Arabinogalactan-Protein from
CarrotDefines aFamily ofBasic Proline-RichProteins .43
T. C. Baldwin, A. J. van Hengel, andK. Roberts
5. Structure and Biosynthesis ofL-FucosylatedArabinogalactan-Proteins in
CruciferousPlants 51
Y. Hashimoto
Xl
XII Contents
SECTION 2: LOCALIZATIONAND ACTION OFARABINOGALACTAN
PROTEINS AT THE SUBCELLULAR AND CELLULARLEVELS
6. Characterization and Localization ofa Novel Tomato Arabinogalactan-Protein
(LeAGP-l) and the Involvement of Arabinogalactan-Proteins in
Programmed Cell Death 61
A. M. Showalter, M. Gao, M. J. KieIiszewski, and D. T. A. Lamport
7. Cell Cycle Arrestby Perturbation ofArabinogalactan-Proteins with Yariv
Phenylglycoside 71
J. A. Eyvazzadeh and E. A. Nothnagel
8. A Major Antimicrobial Hybrid Chitin-Binding Protein from FrenchBean with
Features Common to Arabinogalactan-Proteins and Hydroxyproline-
Rich Glycoproteins 83
G. P. BolweIl, J. B. Trethowan, and P. Wojtaszek
SECTION 3: ARABINOGALACTAN-PROTEINS IN SOMATIC
EMBRYOGENESIS
9. Arabinogalactan-Proteins and Cell Development in Roots and Somatic
Embryos 95
C. G. Steele-King, W. G. T. Willats, and J. P. Knox
10. EffectofArabinogalactan-Proteins and Chitinases on Somatic
Embryogenesis 109
M. Kreuger, A. van Hengel, and S. de Vries
SECTION 4: ARABINOGALACTAN-PROTEINS IN REPRODUCTIVE
DEVELOPMENT
11. Arabinogalactan-Proteins inReproductive Tissues ofFlowering Plants 121
A. E. Clarke, G. Currie, P. Gilson, S.-L. Mau, D. Oxley, C. J. Schultz, J.
Sommer-Knudsen, and A. Bacic
12. Transcriptional, Post-Transcriptional and Post-Translational Regulation ofa
Nicotiana StylarTransmittingTissue-Specific Arabinogalactan-
Protein 133
A. Y. Cheung, X.-Y. Zhan, E. Wong, H. Wang, and H.-M. Wu
