Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2006 Root flavonoids : their transport and role in intra- and extracellular signalling Santelia, Diana Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-163697 Dissertation Published Version Originally published at: Santelia, Diana. Root flavonoids : their transport and role in intra- and extracellular signalling. 2006, University of Zurich, Faculty of Science. Root Flavonoids: their Transport and Role in Intra and Extra Cellular Signalling Dissertation zur Erlangung der naturwissenschaftlichen Doktorwürde (Dr. sc. nat.) vorgelegt der Mathematisch-naturwissenschaftlichen Fakultät der Universität Zürich von Diana Santelia aus Italien Promotionskomitee Prof. Dr. Enrico Martinoia (Leitung der Dissertation) Prof. Dr. Beat Keller Prof. Dr. Bernd Mueller-Roeber Dr. Markus Geisler Dr. Markus Klein Zürich, 2006 TABLE OF CONTENTS SUMMARY .......................................................................................................................................4 ZUSAMMENFASSUNG ..................................................................................................................6 1 INTRODUCTION.....................................................................................................................9 1.1 FLAVONOIDS.............................................................................................................................................10 1.1.1 Chemical structure and classification ..........................................................................................................10 1.1.2 Flavonoid metabolism ................................................................................................................................16 1.1.3 Multiple biological roles of flavonoids .........................................................................................................20 1.2 ROLE OF FLAVONOIDS AS SIGNAL MOLECULES IN PLANT-MICROORGANISM INTERACTIONS: WHITE LUPIN AS A PARADIGM...............................................................................22 1.2.1 Potential plant-microbe interactions in the rhizosphere................................................................................22 1.2.2 White lupin’s rhizosphere as a paradigm ...................................................................................................23 1.3 ROOT EXUDATION: WHICH TRANSPORTERS?.........................................................................31 1.3.1 Cellular mechanisms of root exudation.......................................................................................................32 1.3.2 ABC transporters......................................................................................................................................35 1.3.3 MATE transporters .................................................................................................................................38 1.4 ROLE OF FLAVONOIDS IN PLANT DEVELOPMENT..............................................................39 1.4.1 Flavonoids as intra signalling molecules .....................................................................................................39 1.4.2 Auxin and polar auxin transport..............................................................................................................41 1.4.3 Regulation of polar auxin transport ...........................................................................................................48 1.4.4 Flavonoids as endogenous regulators of polar auxin transport.....................................................................51 1.4.5 Flavonoids and gravitropism ......................................................................................................................52 1.4.6 Flavonoids and cell growth .........................................................................................................................55 2 AIM OF THE WORK .............................................................................................................. 57 3 RESULTS ................................................................................................................................. 58 3.1 Isoflavonoid exudation from white lupin roots is influenced by phosphate supply, root type and cluster-root stage ......................................................................................................................................................59 3.2 White lupin has a complex strategy to limit microbial degradation of secreted citrate required for phosphate acquisition ..............................................................................................................................................74 3.3 P-responsive MATE genes in white lupin roots are possible candidates for isoflavonoid and citrate secretion.........................................................................................................................................................84 3.4 Altered profile of secondary metabolites in the root exudates of Arabidopsis ATP-Binding Cassette (ABC) transporter mutants ...................................................................................................................100 3.5 MDR-like ABC transporter AtPGP4 is involved in auxin-mediated lateral root and root hair development............................................................................................................................................................126 3.6 Flavonoids redirect PIN-mediated polar auxin fluxes during gravitropic responses ......................135 3.7 The modified flavonol glycosylation profile in the Arabidopsis rol1 mutants results in alterations in plant growth and cell shape formation ..........................................................................................................159 4 CONCLUSION AND OUTLOOK.........................................................................................190 5 APPENDIX A......................................................................................................................... 202 6 APPENDIX B ........................................................................................................................ 208 7 CURRICULUM VITAE - JANUARY 2008 -...........................................................................213 8 REFERENCES .......................................................................................................................218 Acknowledgments ACKNOWLEDGMENTS I would like to express my sincere gratitude to everyone who made this possible… First and foremost, my thanks go to Enrico for his constant support and for truly understanding me in each different situation I experienced in the last 4 years, beyond the scientific subjects. My deepest appreciation for letting me think on my own, even when our ideas where not on the same track. On the other hand, thank you for dropping in the right tips at the right moments. I wish to thank you the NCCR Plant Survival Doctoral School. Being a member of this school has provided me with invaluable opportunities to bolster my scientific knowledge and my technical skills, representing the first step towards a future career in academic science. I am grateful to Markus Geisler and Markus Klein for fruitful collaborations, helpful and motivating discussions and for their constant help and support. My sincerest thanks go to Christoph Ringli for fruitful collaboration and for having shared with me the discovery that flavonoids have a more than ever expected impact on plant growth and development. I want to express my gratitude to the exceptional “white lupin team”: Laure for making me realize that you can look at the world from very different points of view; and Nicola for being silently but constantly by my side and for the friendship we share. Many thanks to my friends the “little hobbits” Magali and Ulrike, for their boundless energy and enthusiasm and for holding me in all the difficult situations I faced. Thank you for giving me the strength to go on. My deepest appreciation goes to Vincent, my trusted friend, for its generous and precious technical assistance, and especially for making me feel at home during the many hours of work together. My thanks also to Mika Jasinski, my friend and lab-mate, for all the technical tips, suggestions and support during the many unsucceful days in the lab. Thanks to all present and former members of the Hobbits’s lab and Geisler’s lab for making my daily life in the lab easier and happier. In particular, I am grateful to Aurelien, the happy, fatty, lazy boy, very generous and always ready to help; and to Sina for sharing her smiling approach to life with me and for the help in translating the thesis summary. I will never learn German! Thanks to all the “Klein girls”, and especially to Krasi because the last 4 years have seen us been asked to travel parallel and sometimes overlapping path, and we did it with great respect and friendship. Many thanks to Felix, Monika and Shaun for their constant help in dealing with the fascinating and complex world of the HPLC. Deep thanks to all the people in the Institute for the nice chats, discussions and help, and special thanks to the werkstatt staff for the amaizing work they do every day. I am grateful to all the collaborators, especially to