Characterization of grazer‐induced responses in the marine dinoflagellate Alexandrium tamarense Sylke Wohlrab Dissertation zur Erlangung des Akademischen Grades eines Doktors der Naturwissenschaften ‐ Dr. rer. Nat.‐ im Fachbereich 2 (Biologie & Chemie) der Universität Bremen vorgelegt von Sylke Wohlrab 2013 1. Gutachter: Prof. Dr. Allan Cembella Alfred-Wegener-Institut für Polar- und Meeresforschung Bremerhaven Universität Bremen 2. Gutachter: Prof. Dr. Ralph Tollrian Lehrstuhl für Evolutionsökologie und Biodiversität der Tiere Ruhr-Universität Bochum CONTENTS Table of Contents Erklärung gemäß § 6 (5) .............................................................................................................I Danksagung ................................................................................................................................ II Summary .................................................................................................................................... III Zusammenfassung ................................................................................................................... VI Abbreviations ............................................................................................................................ IX 1. Introduction ........................................................................................................................ 1 1.1 Species Interactions ................................................................................................... 1 1.2 Top-down and bottom-up control ........................................................................... 2 1.3 Harmful algal blooms ................................................................................................ 3 1.4 Dinoflagellates ............................................................................................................ 5 1.5 The Alexandrium tamarense species complex ..................................................... 8 1.5.1 Toxic blooms of Alexandrium tamarense ................................................... 12 1.5.2 Grazing by microzooplankton ....................................................................... 13 1.5.3 Grazing by copepods ...................................................................................... 15 1.4 Induced defense ........................................................................................................ 18 1.5 Secondary metabolites ............................................................................................ 20 1.6 Genes involved in species interactions ................................................................ 22 2. Aim and outline of the thesis ........................................................................................ 25 2.1. Justification and aim of the thesis ........................................................................ 25 2.2 Outline and approach of the thesis ...................................................................... 26 3. Publications ....................................................................................................................... 29 3.1 List of publications and declaration of contribution ............................................. 29 3.2 Further publications ..................................................................................................... 30 CONTENTS 4. A molecular and co-evolutionary context for grazer induced toxin production in Alexandrium tamarense ............................................................. 31 4.1 Abstract ...................................................................................................................... 31 4.2 Introduction ............................................................................................................... 31 4.3 Material and Methods .............................................................................................. 34 4.4 Results ........................................................................................................................ 39 4.5 Discussion .................................................................................................................. 46 4.6 Conclusions ............................................................................................................... 51 5. Fight and flight in dinoflagellates? Kinetics of simultaneous grazer-induced responses in Alexandrium tamarense ............................................. 52 5.1 Abstract ...................................................................................................................... 52 5.2 Introduction ............................................................................................................... 52 5.3 Material and Methods .............................................................................................. 54 5.4 Results ........................................................................................................................ 58 5.5 Discussion .................................................................................................................. 62 5.6 Conclusions ............................................................................................................... 65 6. Grazer induced reaction norms - a transcriptomic comparison ............................ 66 5.1 Abstract ...................................................................................................................... 66 5.2 Introduction ............................................................................................................... 66 5.3 Material and Methods .............................................................................................. 70 5.4 Results ........................................................................................................................ 76 5.5 Discussion .................................................................................................................. 86 5.6 Conclusions ............................................................................................................... 92 6. Mapping genotypic trait alterations in A. tamarense in response to a protistan grazer ................................................................................. 93 6.1 Abstract ...................................................................................................................... 93 6.2. Introduction ............................................................................................................... 94 CONTENTS 6.3 Material and Methods .............................................................................................. 97 6.4 Results ...................................................................................................................... 102 6.5 Discussion ................................................................................................................ 109 6.6 Conclusions ............................................................................................................. 114 7. Assembly and functional annotation of a comprehensive expression based gene library to study biotic interactions in the marine dinoflagellate Alexandrium tamarense ............................................ 115 7.1 Abstract .................................................................................................................... 115 7.2 Introduction ............................................................................................................. 115 7.3 Material and Methods ............................................................................................ 118 7.4 Results and Discussion ......................................................................................... 122 7.5 Conclusions ............................................................................................................. 131 8. Synthesis .......................................................................................................................... 132 8.1 Induced defense against copepods ..................................................................... 133 8.1.1 Signal specificity and induced defense ...................................................... 134 8.1.2 Grazer induced defense responses and trade-offs .................................. 135 8.1.3 PSTs as defense compounds ........................................................................ 136 8.1.4 Transcriptomic and strain-specific responses towards copepod grazers ............................................................................. 137 8.2 Genotype specific feedback responses towards a protistan grazer ............. 140 8.2.1 Genotype specific gene expression patterns ............................................ 141 8.2.2 Genotype specific trait alterations inferred from functional genomics ............................................................ 142 8.3 Future perspectives ................................................................................................ 144 References ............................................................................................................................... 149 Supplemental material ......................................................................................................... 174 ERKLÄRUNG Sylke Wohlrab Rheinstr. 48 27570 Bremerhaven Erklärung gemäß § 6 (5) der Promotionsordnung