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Transcription

1 Plant Biotechnology

2 Springer Berlin Heidelberg New York Barcelona Hong Kong London Milan Paris Singapore Tokyo

3 J. Hammond, P. McGarvey, and V. Yusibov (Eds.) Plant Biotechnology New Products and Applications With 12 Figures and 9 Tables, Springer

4 JOHN HAMMOND, Ph.D. USDA-ARS, USNA Florist and Nursery Crops Unit Rm. 238, B-OIOA Baltimore Ave. Beltsville, MD USA PETER MCGARVEY, Ph.D. National Biomedical Research Foundation Georgetown University Medical Center LR-3, Preclinical Science Building 3900 Reservoir Road, NW Washington, DC USA Professor VIDALDI YUSIBOV, Ph.D. Biotechnology Foundation Labs. Thomas Jefferson University Rm. M85, JAH, 1020 Locust Street Philadelphia, PA USA Cover Illustration: The expression of pharmaceuticals and vaccines in transgenic plants and from genetically engineered plant viruses (molecular farming) are symbolized by a plant-containing syringe, virus particles, and antibody molecules. Cover Design: design & production GmbH, Heidelberg ISBN-13: Springer-Verlag Berlin Heidelberg New York Second Printing 1999 (originally published in CURRENT ToPICS IN MICROBIOLOGY AND IMMUNOLOGY, Vol. 240, ISBN , /999) Cataloging-in-Publication Data applied for Die Deutsche Bibliothek - CIP-Einheitsaufnahme Plant Biotechnology: new products and applications; with 9 tables 1 ed. by John Hammond printing. - Berlin; Heidelberg; New York; Barcelona; Hong Kong; London; Milan; Paris; Singapore; Tokyo: Springer, 1999 ISBN-13:978-3-S e-isbn-13: DOl: / This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. Springer-Verlag Berlin Heidelberg 2000 Library of Congress Catalog Card Number The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Product liability: The publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every individual case the user must check such information by consulting other relevant literature. Typesetting: Scientific Publishing Services (Pl Ltd, Madras Production Editor: Angelique Gcouta SPIN: / Printed on acid-free paper

5 Preface The title of this volume, Plant Biotechnology: Nell' Products and Applications, may look a little out of place among previous volumes of Current Topics in Microbiology and Immunology that have focused mostly on issues related to human health and animal biology, However, plant biology has always been of immense practical importance, and has enjoyed an intimate relationship with medicine and other biological sciences for centuries, Increasing scientific specialization and the dramatic advances in the medical and chemical sciences during this century have left many persons with the impression that plant biology and plant biotechnology is important only in relation to the agricultural sciences, This is no longer true. Within the past year a genetically engineered plant virus has been used to vaccinate and protect against an animal disease (see the chapter by Lomonossoff and Hamilton), the first human trials of a potential transgenic plantbased oral vaccine against cholera have been conducted (see the chapter by Richter and Kipp), and the first human trial of an injectable transgenic plant-derived therapeutic protein is under way (discussed in the chapter by Russell et al.). Today plant biotechnology is being used in new and creative ways to produce therapeutic products for medicine and plastics for industry as well as new disease- and stress-resistant crops for agriculture. This volume is intended to introduce some of these new and exciting areas to readers unfamiliar with plant biotechnology and also to serve as a review of ongoing research and future considerations for readers familiar with the field. Since it would be impractical to cover all areas of plant biotechnology in a single volume, we have elected to focus on several of the exciting areas of research in which comparatively little has been published. However, we have included review chapters that touch on most or the current research in plant biotechnology and the basic technology employed to engineer plants and plant viruses. The first chapter by Hammond surveys the field of plant biotechnology from the initial work on pathogen resistance to the current attempts to produce pharmaceuticals and industrial en-

6 VI Preface zymes in plants. This is an excellent chapter for readers interested in learning about the wide variety of research accomplishments in plant biotechnology and how some of the research discussed in the following chapters fits into the overall status of the field. The chapter by Hansen and Chilton reviews Agrobacteriummediated transformation, the most commonly used method for engineering dicotyledonous crops. Agrobacterium have evolved a system for infecting wounded plants and inserting genes into the plant nucleus. Some of these genes cause tumor formation and other genes produce opines (amino acid analogues) that the bacteria can then use as an energy source. Microbiologists have adapted this system by deleting the genes that cause tumor formation and opine production and replacing them with recombinant DNA of the researchers choice. Advantages of Agrobacterium-mediated transformation include the typical insertion of one or only a few copies of the transgene into actively transcribed regions of the plant genome. The chapter by Finer et al. covers the second major method of transformation, particle bombardment or biolistic transformation, which is generally favored for transformation of monocotyledonous plant species. Particle bombardment is also used for some dicotyledonous plants that do not regenerate efficiently after Agrobacterium-mediated transformation. Advantages of particle bombardment are that it can be adapted to most all plant species. However, particle bombardment often results in complex transgene insertion loci, which may cause gene silencing in some instances. The chapter by Yusibov et al. discusses a new method of transiently engineering plants for the expression of recombinant proteins using genetically engineered plant viruses. This method does not change the genetic makeup of the host plant. Plant viruses engineered to contain recombinant genes have expressed high levels of medically and industrially important proteins in the field. In addition to the expression of full-length proteins, viral capsid proteins have the potential to express small pep tides on the virions surface. The chapter by Yusibov et al. and that by Lomonossoff and Hamilton each describe how the expression of peptide antigens on the surface of plant viruses can be used to vaccinate and protect animals against viral infections. The chapter by Cramer et al. contains an excellent discussion of the potential benefits and challenges in using transgenic plants for production of therapeutic proteins. Cramer et al. discuss two different types of production systems that were designed for ease of postharvest processing. In the first, transgene expression during the growing season is minimized by having the gene regulated

7 Preface VII by a strong wound-inducible promoter. Thus any potentially deleterious effect on the plant of transgene expression is avoided, no energy is wasted by the crop in producing a product that might be degraded prior to harvest, and greater biomass can be attained. The fresh leaf tissue is harvested to meet demand or is stored under refrigeration until needed. Transgene expression is induced a few hours prior to extraction and processing. so that all of the purified product is recently synthesized. The second approach discussed by Cramer et al. is the fusion of the product of interest to a seed-storage protein of Brassim /l({piis; in this system the fusion protein is targeted to the oil bodies that accumulate in rapeseed following expression from a seed-specific promoter. Rapeseed (and the oil bodies therein) are stahle for years, with minimal storage requirements. Russell examines the various factors that must be considered in the expression of antibodies in transgenic plants. from expression levels to glycosylation, and from bioequivalency to regulatory considerations. Indeed, the first human clinical trial of an injectable transgenic plant-derived therapeutic protein is currently under way. Russell also factors in some cost analyses that must be considered, for example, time-to-market figures, and compares the regulatory burden for therapeutic products to that for transgenic plants designed for food use. Russell also addresses the agronomic and plant-breeding strategies that can be applied once a promising transgenic line has been selected. in order to both stabilize the gene and maximize production. Finally. Russell discusses compliance with good manufacturing practices. which is the basis for preparing an application for a product to be accepted for pharmaceutical use. The chapter by Richter and Kipp provides an excellent review of research using transgenic plants directly as oral vaccines without additional purification steps. Indeed. phase I clinical trials have been completed in which human subjects ate transgenic potatoes containing a potential oral vaccine against cholera. In addition to using transgenic plants to vaccinate against infectious pathogens. there is evidence that they can he used to induce immune tolerance that may prove effective against autoimmune diseases. The chapter by Tumer et al. discusses a slightly more traditional relationship between medicine and plant biology in which plants provide useful drugs for medicine. Pokeweed antiviral protein belongs to a class of proteins called ribosome-inactivating proteins that are used by plants as a defense against pathogens. Many of these proteins have demonstrated medical applications against animal pathogens. Plant biotechnolog~ allows us to

8 VIII Preface rapidly investigate the function of a potential medicine and to produce it in high quantities in crop plants. The advances of the past decade may herald a new "Agricultural Revolution" that will rival the "Green Revolution" of the twentieth century. Further developments in plant biotechnology will no doubt follow those described here. The ability to control gene expression in specific tissues, and especially to induce expression in response to externally applied stimuli, are likely to become increasingly precise. The number of species that can be routinely transformed will certainly grow, and can be expected to include all of the major agronomic crops. This will allow increased choice of production areas to fill specific markets and greater selection of storage organs for the expression of products with distinct processing requirements. A further benefit of improved spatial and temporal control of gene expression could be the production of two or more commodities from different tissues of the same crop. The ability to manipulate multiple genes will allow transfer of increasingly complex pathways from one species to another, and allow utilization of biochemistry in planta to supplant some of the complexities and pollution from chemical plants. Plants that resist disease or predation, without the application of pesticides that also affect beneficial insects, are another example of how agricultural biotechnology has the potential to bring about an environmentally friendly "Agricultural Revolution". Peter McGarvey

9 List of Contents J. HAMMOND Overview: The Many Uses and Applications of Transgenic Plants.... G. HANSEN and M.D. CHILTON Lessons in Gene Transfer to Plants by a Gifted Microbe. 21 J.1. FINER, K.R. FINER, and T. PONAPPA Particle Bombardment Mediated Transformation V. YUSIBOV, S. SHIVPRASAD, T.H. TURPEN, W. DAWSON, and H. KOPROWSKI Plant Viral Vectors Based on Tobamoviruses c.l. CRAMER, J.G. BOOTHE, and K.K. OISHI Transgenic Plants for Therapeutic Proteins: Linking Upstream and Downstream Strategies D.A. RUSSELL Feasibility of Antibody Production in Plants for Human Therapeutic Use N.E. TUMER, K. HUDAK, R. 01, C. COETZER, P. WANG, and O. ZOUBENKO Pokeweed Antiviral Protein and Its Applications L. RICHTER and P.B. KIPp Transgenic Plants as Edible Vaccines G.P. LOMONOSSOFF and W.D.O. HAMILTON Cowpea Mosaic Virus-Based Vaccines Subject Index

10 List of Contributors (Their addresses can be found at the beginning of their respective chapters.) BOOTHE, J.G. 95 CHILTON, M.D. 21 COETZER, C. 139 CRAMER, c.l. 95 DAWSON, W , R. 139 FINER, J FINER, K.R. 59 HAMILTON, W.D.O. 177 HAMMOND, J. HANSEN, G. 21 HUDAK, K. 139 KOPROWSKI, H. 81 LOMONOSSOFF. G.P. 177 OISHI, K.K. 95 PONAPPA. T. 59 RICHTER. L. 159 RUSSELL. D.A. 119 SHIVPRASAD, S. 81 TUMER. N.E. 139 TURPEN. T.H. 81 WANG. P. 139 YUSIBOV. V. 81 ZOlJBENKO. O. 139 KIPP, P.B. 159