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M ETHODS IN M OLECULAR B IOLOGY Series Editor John M. Walker School of Life Sciences University of Hertfordshire Hatfield, Hertfordshire, AL10 9AB, UK For further volumes: http://www.springer.com/series/7651

Transcript of M ETHODS IN M OLECULAR B IOLOGY - Home - Springer978-1-4939-1695-5/1.pdf · M ETHODS IN M OLECULAR...

M E T H O D S I N M O L E C U L A R B I O L O G Y

Series EditorJohn M. Walker

School of Life SciencesUniversity of Hertfordshire

Hat fi eld, Hertfordshire, AL10 9AB, UK

For further volumes: http://www.springer.com/series/7651

Agrobacterium Protocols

Volume 1

Third Edition

Edited by

Kan Wang

Center for Plant Transformation, Plant Sciences Institute, and Department of Agronomy, Iowa State University, Ames, IA, USA

ISSN 1064-3745 ISSN 1940-6029 (electronic)ISBN 978-1-4939-1694-8 ISBN 978-1-4939-1695-5 (eBook) DOI 10.1007/978-1-4939-1695-5 Springer New York Heidelberg Dordrecht London

Library of Congress Control Number: 2014948257

© Springer Science+Business Media New York 2015 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifi cally for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.

Printed on acid-free paper

Humana Press is a brand of SpringerSpringer is part of Springer Science+Business Media (www.springer.com)

Editor Kan Wang Center for Plant TransformationPlant Sciences Institute Department of Agronomy Iowa State University Ames , IA , USA

To Marc Van Montagu and Jeff Schell (1935–2003), my Ph.D. mentors, for their inspiration and encouragement.

Dedication

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Agrobacterium tumefaciens is a soil bacterium that for more than a century has been known as a pathogen causing the plant crown gall disease. Unlike many other pathogens, Agrobacterium is able to deliver DNA to plant cells and permanently alter the plant genome. The discovery of this unique feature has provided plant scientists with a powerful tool to genetically transform plants for both basic research purposes and for agricultural advancement.

The fi rst transgenic plants were reported a little over 30 years ago in 1983 by three independent research groups. Using disarmed Agrobacterium vectors, these groups pro-duced antibiotic-resistant transgenic tobacco Nicotiana tobaccum (Herrera-Estralla et al., 1983, Nature 303: 209), Nicotiana plumbaginifolia (Bevan et al., 1983, Nature 304: 184), and petunia ( Petunia hybrid , Fraley et al., 1983, Proceedings of the National Academy of Sciences 80: 4803). The three scientists who led the landmark work, Marc Van Montagu, Mary-Dell Chilton, and Robert Fraley, were the laureates for the 2013 World Food Prize ( http://www.worldfoodprize.org/en/laureates/2013_laureates/#StatementAchievement ). As the statement of achievement of the World Food Prize says, “… each conducted groundbreaking molecular research on how a plant bacterium could be adapted as a tool to insert genes from another organism into plant cells, which could produce new genetic lines with highly favorable traits.”

While other methods such as biolistic gun, electroporation, or polyethylene glycol can also be used for introducing DNA molecules into plant cells, the Agrobacterium -mediated transformation method remains the method of choices for most plant species in many labo-ratories due to its effi ciency and its propensity to generate single or a low copy number of integrated transgenes with defi ned ends.

When the fi rst edition of Agrobacterium Protocols was published in 1995, exactly 20 years ago, only a handful of plants could be routinely transformed using Agrobacterium . The second edition, which was published in 2006, collected transformation protocols for 59 plant species. In this third edition, we have updated protocols for 32 plant species from the second edition and added protocols for 17 new species. Together with the fi rst and second editions, these two new volumes offer Agrobacterium -mediated genetic transforma-tion protocols for a total of 76 plant species.

The third edition of Agrobacterium Protocols contains 57 chapters (two volumes) divided into 9 parts. This edition emphasizes on agricultural crops or plant species with economic values. For a number of important plants such as rice, barley, wheat, and citrus, multiple protocols using different starting plant materials for transformation are included. Like the second edition, plants are grouped according to their practical uses rather than their botanical classifi cations.

Agrobacterium Protocols provides a benchtop manual for tested protocols involving Agrobacterium -mediated transformation. All chapters are written in the same format as that used in the Methods in Molecular Biology series. Each chapter is contributed by authors who are leaders or veterans in their respective areas. The “Abstract” and “Introduction” sec-tions provide outlines of protocols, the rationale for selection of particular target tissues, and information regarding overall transformation effi ciency. The “Materials” section lists the host materials, Agrobacterium strains and vectors, stock solutions, media, and other supplies

Pref ace

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necessary for carrying out these transformation experiments. The “Methods” section is the core of each chapter. It provides a step-by-step description of the entire transformation pro-cedure from the preparation of starting materials to the harvest of transgenic plants. To ensure the reproducibility of each protocol, the “Notes” section lists possible pitfalls in the protocol and suggests alternative materials or methods for generating transgenic plants.

Typically, most laboratories only work on one or a few plant species. Each laboratory or individual researcher has his or her own favorite variation or modifi cation of any given plant transformation protocol. The protocols presented in this edition represent the most effi -cient methods used in the laboratories of the contributors. They are by no means the only methods for successful transformation of your plant of interest.

The broad range of target tissue selection and in vitro culture procedures indicate the complexity in plant transformation. It is the intention of this book to facilitate the transfer of this rapidly developing technology to all researchers for use in both fundamental and applied biology. I take this opportunity to thank all my colleagues whose time and effort made this edition possible. Special thanks go to my family for their unconditional love and support during the process of editing this book.

Ames, IA, USA Kan Wang

Preface

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Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

PART I VECTORS AND MODEL PLANTS

1 Gateway®-Compatible Plant Transformation Vectors . . . . . . . . . . . . . . . . . . . . 3 Mark A. Smedley and Wendy A. Harwood

2 Brachypodium distachyon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Jennifer N. Bragg, Amy Anderton, Rita Nieu, and John P. Vogel

3 Medicago truncatula Transformation Using Cotyledonary Explants. . . . . . . . . 35 Elane Wright and Zeng-Yu Wang

4 Medicago truncatula Transformation Using Leaf Explants . . . . . . . . . . . . . . . . 43 Viviane Cosson, Alexis Eschstruth , and Pascal Ratet

5 Setaria viridis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Joyce Van Eck and Kerry Swartwood

PART II CEREAL PLANTS

6 Barley (Hordeum vulgare L.) Transformation Using Immature Embryos . . . . . 71 Cornelia Marthe, Jochen Kumlehn, and Goetz Hensel

7 Barley (Hordeum vulgare L.) Transformation Using Embryogenic Pollen Cultures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Ingrid Otto, Andrea Müller, and Jochen Kumlehn

8 Maize (Zea mays L.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Bronwyn Frame, Katey Warnberg, Marcy Main, and Kan Wang

9 Maize, Tropical (Zea mays L.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Shireen K. Assem

10 Finger millet [Eleusine coracana (L.) Gaertn.] . . . . . . . . . . . . . . . . . . . . . . . . . 135 Stanislaus Antony Ceasar and Savarimuthu Ignacimuthu

11 Oat (Avena sativa L.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Sebastian Gasparis and Anna Nadolska-Orczyk

12 Rice, Indica (Oryza sativa L.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 Yukoh Hiei, Yuji Ishida, and Toshihiko Komari

13 Rice, Japonica (Oryza sativa L.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Marcy Main, Bronwyn Frame, and Kan Wang

14 Sorghum (Sorghum bicolor ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 Xiaomei Guo, Zhengxiang Ge, Shirley J. Sato, and Tom E. Clemente

Contents

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15 Wheat (Triticum aestivum L.) Transformation Using Immature Embryos . . . . 189 Yuji Ishida, Masako Tsunashima, Yukoh Hiei, and Toshihiko Komari

16 Wheat (Triticum aestivum L.) Transformation Using Mature Embryos . . . . . . 199 Eva Medvecká and Wendy A. Harwood

PART III LEGUME PLANTS

17 Alfalfa (Medicago sativa L.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Chunxiang Fu, Timothy Hernandez, Chuanen Zhou, and Zeng-Yu Wang

18 Clovers (Trifolium spp.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 Samira Rahimi-Ashtiani, Sareena Sahab, Stephen Panter, John Mason, and German Spangenberg

19 Clover, Red (Trifolium pratense) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 Michael L. Sullivan and Kenneth H. Quesenberry

20 Cowpea [Vigna unguiculata (L.) Walp.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255 Ratikanta Behura, Sanjeev Kumar, Bedabrata Saha, Manasa Kumar Panda, Mohitosh Dey, Ayan Sadhukhan, Sagarika Mishra, Shamsher Alam, Debee Prasad Sahoo, Twinkle Sugla, and Lingaraj Sahoo

21 Lentil (Lens culinaris Medik). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265 Ufuk Celikkol Akcay, Meral Yücel, and Hüseyin Avni Öktem

22 Soybean [Glycine max (L.) Merr.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 Diane Luth, Katey Warnberg, and Kan Wang

PART IV VEGETABLE PLANTS

23 Brassica oleracea and B. napus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 Penny A. C. Hundleby née Sparrow and Judith A. Irwin

24 Cucumber (Cucumis sativus L.) and Kabocha Squash (Cucurbita moschata Duch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Yoshihiko Nanasato and Yutaka Tabei

25 Pepper, Chili (Capsicum annuum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 Jung Min, Sun Hee Shin, En Mi Jeon, Jung Mi Park, Ji Young Hyun, and Chee Hark Harn

26 Pepper, Sweet (Capsicum annuum). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321 Iris Heidmann and Kim Boutilier

27 Sugar Beet (Beta vulgaris L.). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 Hiroyo Kagami, Masayuki Kurata, Hiroaki Matsuhira, Kazunori Taguchi, Tetsuo Mikami, Hideto Tamagake, and Tomohiko Kubo

28 Tomato (Solanum lycopersicum). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349 Dora Garcia, Javier Narváez-Vásquez, and Martha L. Orozco-Cárdenas

Erratum to. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E1

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363

Contents

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SHAMSHER ALAM • Department of Biotechnology , Indian Institute of Technology Guwahati , Guwahati , India

AMY ANDERTON • USDA-ARS, Western Regional Research Center , Albany , CA , USA SHIREEN K. ASSEM • Agricultural Genetic Engineering Research Institute (AGERI) ,

Agricultural Research Center (ARC) , Giza , Egypt RATIKANTA BEHURA • Department of Biotechnology , Indian Institute of Technology

Guwahati , Guwahati , India KIM BOUTILIER • Plant Research International , Wageningen University and Research

Centre , Wageningen , The Netherlands JENNIFER N. BRAGG • USDA-ARS, Western Regional Research Center , Albany , CA , USA STANISLAUS ANTONY CEASAR • Centre for Plant Sciences, Faculty of Biological Sciences ,

University of Leeds , Leeds , UK; Division of Plant Biotechnology, Entomology Research Institute, Loyola College, Chennai, TN, India

UFUK CELIKKOL AKCAY • Department of Agricultural Biotechnology , Suleyman Demirel University , Isparta , Turkey

TOM E. CLEMENTE • Department of Agronomy and Horticulture, Center for Plant Science Innovation , George W. Beadle Center, University of Nebraska-Lincoln , Lincoln , NE , USA

VIVIANE COSSON • Institut des Sciences du Végétal , Saclay Plant Sciences, CNRS , Gif sur Yvette Cedex , France

MOHITOSH DEY • Department of Biotechnology , Indian Institute of Technology Guwahati , Guwahati , India

ALEXIS ESCHSTRUTH • Institut des Sciences du Végétal , Saclay Plant Sciences, CNRS , Gif sur Yvette Cedex , France

BRONWYN FRAME • Center for Plant Transformation, Plant Sciences Institute, and Department of Agronomy , Iowa State University , Ames , IA , USA

CHUNXIANG FU • Forage Improvement Division , The Samuel Roberts Noble Foundation , Ardmore , OK , USA

DORA GARCIA • Plant Transformation Research Center , University of California , Riverside , CA , USA

SEBASTIAN GASPARIS • Department of Functional Genomics, Plant Breeding and Acclimatization Institute , National Research Institute , Radzikow , Błonie , Poland

ZHENGXIANG GE • Department of Agronomy and Horticulture, Center for Plant Science Innovation , George W. Beadle Center, University of Nebraska-Lincoln , Lincoln , NE , USA

XIAOMEI GUO • Department of Agronomy and Horticulture, Center for Plant Science Innovation , George W. Beadle Center, University of Nebraska-Lincoln , Lincoln , NE , USA

CHEE HARK HARN • Biotechnology Institute , Yeoju , Gyeonggi , South Korea WENDY A. HARWOOD • Department of Crop Genetics , John Innes Centre, Norwich Research

Park , Norwich , UK IRIS HEIDMANN • Enza Zaden Research and Development B.V. , Enkhuizen , The Netherlands GOETZ HENSEL • Plant Reproductive Biology , Leibniz Institute of Plant Genetics and Crop

Plant Research (IPK) , Stadt Seeland , OT Gatersleben , Germany

Contributors

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TIMOTHY HERNANDEZ • Forage Improvement Division , The Samuel Roberts Noble Foundation , Ardmore , OK , USA

YUKOH HIEI • Plant Innovation Center , Japan Tobacco Inc , Iwata , Shizuoka , Japan PENNY A. C. HUNDLEBY NÉE SPARROW • Department of Crop Genetics , John Innes Centre,

Norwich Research Park , Norwich , UK JI YOUNG HYUN • Biotechnology Institute , Yeoju , Gyeonggi , South Korea SAVARIMUTHU IGNACIMUTHU • Division of Plant Biotechnology, Entomology Research

Institute , Loyola College , Chennai , TN, India JUDITH A. IRWIN • Department of Crop Genetics , John Innes Centre,

Norwich Research Park , Norwich , UK YUJI ISHIDA • Plant Innovation Center , Japan Tobacco Inc. , Iwata , Shizuoka , Japan EN MI JEON • Biotechnology Institute , Yeoju , Gyeonggi , South Korea HIROYO KAGAMI • Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan TOSHIHIKO KOMARI • Plant Innovation Center , Japan Tobacco Inc. , Iwata , Shizuoka , Japan TOMOHIKO KUBO • Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan SANJEEV KUMAR • Department of Biotechnology , Indian Institute of Technology Guwahati ,

Guwahati , India JOCHEN KUMLEHN • Plant Reproductive Biology , Leibniz Institute of Plant Genetics

and Crop Plant Research (IPK) Gatersleben , Stadt Seeland , OT , Germany MASAYUKI KURATA • Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan DIANE LUTH • Center for Plant Transformation, Plant Sciences Institute , and Department

of Agronomy , Iowa State University , Ames , IA , USA MARCY MAIN • Center for Plant Transformation, Plant Sciences Institute, and Department

of Agronomy , Iowa State University , Ames , IA , USA CORNELIA MARTHE • Plant Reproductive Biology , Leibniz Institute of Plant Genetics

and Crop Plant Research (IPK) , Stadt Seeland , OT Gatersleben , Germany JOHN MASON • School of Applied Systems Biology, AgriBio, Centre for AgriBioscience,

La Trobe University, Bundoora, VIC, Australia; Biosciences Research Division, Department of Environment and Primary Industries, AgriBio, Centre for AgriBioscience , La Trobe University , Bundoora, VIC , Australia

HIROAKI MATSUHIRA • Hokkaido Agricultural Research Center (HARC) , National Agriculture and Food Research Organization (NARO) , Sapporo , Japan

EVA MEDVECKÁ • Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, UK; Institute of Science and Technology Austria , Klosterneuburg , Austria

TETSUO MIKAMI • Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan JUNG MIN • Biotechnology Institute , Yeoju , Gyeonggi , South Korea SAGARIKA MISHRA • Department of Biotechnology , Indian Institute of Technology Guwahati ,

Guwahati , India ANDREA MÜLLER • Plant Reproductive Biology , Leibniz Institute of Plant Genetics

and Crop Plant Research (IPK) Gatersleben , Stadt Seeland , OT , Germany ANNA NADOLSKA-ORCZYK • Department of Functional Genomics, Plant Breeding

and Acclimatization Institute , National Research Institute , Radzikow , Błonie , Poland YOSHIHIKO NANASATO • Genetically Modifi ed Organism Research Center, National Institute

of Agrobiological Sciences, Ibaraki, Japan; Faculty of Agriculture , Tottori University , Tottori , Japan

JAVIER NARVÁEZ-VÁSQUEZ • Plant Transformation Research Center , University of California , Riverside , CA , USA

Contributors

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RITA NIEU • USDA-ARS, Western Regional Research Center , Albany , CA , USA HÜSEYIN AVNI ÖKTEM • Department of Biology , Middle East Technical University ,

Ankara , Turkey MARTHA L. OROZCO-CÁRDENAS • Plant Transformation Research Center , University

of California , Riverside , CA , USA INGRID OTTO • Plant Reproductive Biology , Leibniz Institute of Plant Genetics and Crop

Plant Research (IPK) Gatersleben , Stadt Seeland , OT , Germany MANASA KUMAR PANDA • Department of Biotechnology , Indian Institute of Technology

Guwahati , Guwahati , India STEPHEN PANTER • Biosciences Research Division, Department of Environment and Primary

Industries, AgriBio, Centre for AgriBioscience , La Trobe University , Bundoora , VIC , Australia

JUNG MI PARK • Biotechnology Institute , Yeoju , Gyeonggi , South Korea KENNETH H. QUESENBERRY • Department of Agronomy , University of Florida , Gainesville ,

FL , USA SAMIRA RAHIMI-ASHTIANI • School of Applied Systems Biology, AgriBio, Centre for AgriBioscience ,

La Trobe University , Bundoora , VIC , AustraliaPASCAL RATET • Institut des Sciences du Végétal, Saclay Plant Sciences, CNRS, Gif sur Yvette,

Cedex, France AYAN SADHUKHAN • Department of Biotechnology , Indian Institute of Technology Guwahati ,

Guwahati , India BEDABRATA SAHA • Department of Biotechnology , Indian Institute of Technology Guwahati ,

Guwahati , India ; Department of Life Sciences and Bioinformatics , Assam University , Silchar , India

SAREENA SAHAB • Biosciences Research Division, Department of Environment and Primary Industries, AgriBio, Centre for AgriBioscience , La Trobe University , Bundoora , VIC , Australia

DEBEE PRASAD SAHOO • Department of Biotechnology , Indian Institute of Technology Guwahati , Guwahati , India

LINGARAJ SAHOO • Department of Biotechnology , Indian Institute of Technology Guwahati , Guwahati , India

SHIRLEY J. SATO • Department of Agronomy & Horticulture, Center for Plant Science Innovation , George W. Beadle Center, University of Nebraska-Lincoln , Lincoln , NE , USA

SUN HEE SHIN • Biotechnology Institute , Yeoju , Gyeonggi , South Korea MARK A. SMEDLEY • Department of Crop Genetics , John Innes Centre, Norwich Research

Park , Norwich , UK GERMAN SPANGENBERG • School of Applied Systems Biology, AgriBio, Centre for

AgriBioscience, La Trobe University, Bundoora, VIC, Australia; Biosciences Research Division, Department of Environment and Primary Industries, AgriBio, Centre for AgriBioscience , La Trobe University , Bundoora , VIC , Australia

TWINKLE SUGLA • Department of Biotechnology , Indian Institute of Technology Guwahati , Guwahati , India

MICHAEL L. SULLIVAN • Agricultural Research Service, U.S. Department of Agriculture , U.S. Dairy Forage Research Center , Madison , WI , USA

KERRY SWARTWOOD • Boyce Thompson Institute for Plant Research , Ithaca , NY , USA YUTAKA TABEI • Genetically Modifi ed Organism Research Center , National Institute

of Agrobiological Sciences , Ibaraki , Japan

Contributors

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KAZUNORI TAGUCHI • Memuro Upland Farming Research Station , HARC/NARO , Memuro , Japan

HIDETO TAMAGAKE • Central Agricultural Experiment Station, Agriculture Research Department , Hokkaido Research Organization , Takikawa , Japan

MASAKO TSUNASHIMA • Plant Innovation Center , Japan Tobacco Inc. , Iwata , Shizuoka , Japan JOYCE VAN ECK • Boyce Thompson Institute for Plant Research , Ithaca , NY , USA JOHN P. VOGEL • US Department of Energy Joint Genome Institute , Walnut Creek ,

CA , USA KAN WANG • Center for Plant Transformation, Plant Sciences Institute, and Department

of Agronomy , Iowa State University , Ames , IA , USA ZENG-YU WANG • Forage Improvement Division , The Samuel Roberts Noble Foundation ,

Ardmore , OK , USA KATEY WARNBERG • Center for Plant Transformation, Plant Sciences Institute,

and Department of Agronomy , Iowa State University , Ames , IA , USA ELANE WRIGHT • Forage Improvement Division , The Samuel Roberts Noble Foundation ,

Ardmore , OK , USA MERAL YÜCEL • Department of Biology , Middle East Technical University , Ankara , Turkey CHUANEN ZHOU • Forage Improvement Division , The Samuel Roberts Noble Foundation ,

Ardmore , OK , USA

Contributors