Aus dem Institut für Pflanzenbau und Pflanzenzüchtung II der Justus-Liebig-Universität Gießen Biometrie und Populationsgenetik Resistance induction in the pathosystem tomato – Alternaria solani Inaugural-Dissertation zur Erlangung des Doktorgrades (Dr. agr.) beim Fachbereich Agrarwissenschaften, Ökotrophologie und Umweltmanagement der Justus-Liebig-Universität Gießen Dipl.-Ing. agr. Maendy Fritz aus Butzbach Gießen 2005 Vorsitzender: Prof. Dr. Ernst-August Nuppenau Erstgutachter: Prof. Dr. Wolfgang Köhler Zweitgutachter: Prof. Dr. Karl-Heinz Kogel 1. Prüfer: Prof. Dr. Sylvia Schnell 2. Prüfer: Prof. Dr. Joachim Sauerborn Disputation: 30. September 2005 Table of Contents TABLE OF CONTENTS 1 INTRODUCTION ...................................................... 1 2 LITERATURE SURVEY .............................................. 3 2.1 The pathosystem tomato – Alternaria solani ....................................... 3 2.2 Chemical plant protection ..................................................................... 6 2.3 Induced resistance ................................................................................. 8 2.4 Spirulina platensis as plant restorative .............................................. 10 2.5 Root symbionts .................................................................................... 11 2.5.1 Plant growth promoting fungus Piriformospora indica .................. 11 2.5.2 Arbuscular mycorrhizal fungi ........................................................ 13 3 MATERIALS AND METHODS ................................... 16 3.1 Plant material ........................................................................................ 16 3.1.1 Tomato plants for general studies ................................................ 16 3.1.1.1 Plant protective agents and plant restoratives ................ 17 3.1.1.2 Leaf disc experiments ..................................................... 18 3.1.2 Plants with root colonising fungus Piriformospora indica .............. 18 3.1.2.1 Plant material with Piriformospora indica ........................ 18 3.1.2.2 Culture of Piriformospora indica ..................................... 19 3.1.3 Plants with arbuscular mycorrhizal fungus G. intraradices ........... 20 3.1.3.1 Plant material with Glomus intraradices .......................... 20 3.1.3.2 Root harvest and estimation of mycorrhizal colonisation 21 I Table of Contents 3.1.3.3 Propagation of Glomus intraradices ................................ 22 3.1.3.4 AMF inoculum EcoMic® .................................................. 22 3.2 Pathogen Alternaria solani .................................................................. 23 3.2.1 Culture of Alternaria solani ........................................................... 23 3.2.2 Inoculation of host plants .............................................................. 23 3.2.3 Assessment of disease severity ................................................... 24 3.3 Experimental designs and statistical analysis ................................... 25 3.3.1 Experimental designs ................................................................... 25 3.3.2 Statistical analysis ........................................................................ 26 3.4 Chemicals and materials ..................................................................... 26 4 RESULTS ............................................................... 29 4.1 General studies of Alternaria solani ................................................... 29 4.1.1 Induction of sporulation ............................................................... 30 4.1.2 Leaf age dependent susceptibility ............................................... 30 4.1.3 Alternaria toxins ........................................................................... 31 4.1.4 Summary ..................................................................................... 32 4.2 Spirulina platensis as plant restorative .............................................. 32 4.2.1 Comparison of soil drench and spraying ..................................... 33 4.2.2 Combination of Spirulina platensis and ASM ............................... 33 4.2.3 Summary ..................................................................................... 36 4.3 Chemical plant protective agent Maneb® ........................................... 37 4.3.1 Maneb in recommended concentration ....................................... 38 4.3.2 Summary ..................................................................................... 38 4.4 Resistance inducer ASM ...................................................................... 39 4.4.1 ASM as soil drench or as spray ................................................... 39 4.4.2 Comparing ASM spray and soil drench in one experiment .......... 41 4.4.3 Combination of Maneb and ASM ................................................. 42 4.4.4 Direct effects of ASM on Alternaria solani ................................... 44 4.4.5 Interactions between Maneb and ASM ........................................ 45 4.4.6 Summary ..................................................................................... 47 4.5 Resistance inducer INA ....................................................................... 47 4.5.1 Phytotoxic side-effects of INA ...................................................... 48 4.5.2 Summary ..................................................................................... 49 II Table of Contents 4.6 Growth promoting fungus Piriformospora indica ............................. 49 4.6.1 P. indica growth promotion in three tomato cultivars ................... 49 4.6.2 Influence of P. indica on Alternaria in vitro .................................. 52 4.6.3 Influence of P. indica on Alternaria infection in vivo ...................... 53 4.6.4 Summary ...................................................................................... 55 4.7 Influence of nutrient supply on Alternaria infection .......................... 55 4.7.1 Phosphorus influence on early blight ............................................ 56 4.7.2 Nitrogen influence on early blight ................................................. 58 4.7.3 Summary ...................................................................................... 59 4.8 Arbuscular mycorrhizal fungi .............................................................. 60 4.8.1 AMF and low P supply influence on Alternaria infection ............... 60 4.8.2 AMF and high P supply influence on Alternaria infection .............. 63 4.8.3 Summary ...................................................................................... 64 4.9 Field trial with ASM, Spirulina and AMF ............................................. 65 5 DISCUSSION ......................................................... 67 5.1 General studies of Alternaria solani ................................................... 67 5.2 Plant restorative Spirulina platensis ................................................... 70 5.3 Chemical plant protective agent Maneb ............................................. 71 5.4 Resitance inducer ASM ........................................................................ 72 5.5 Resistance inducer INA ....................................................................... 77 5.6 Growth promoting fungus Piriformospora indica ............................. 77 5.7 Influence of nutrient supply on Alternaria infection .......................... 78 5.8 Arbuscular mycorrhizal fungi as bioprotrectants .............................. 80 6 MYCORRHIZA INDUCES SUSCEPTIBILITY ............. 85 6.1 Summary ............................................................................................... 85 6.2 Introduction .......................................................................................... 86 6.3 Materials and methods ......................................................................... 87 6.3.1 Experimental design ..................................................................... 87 6.3.2 Biological materials ....................................................................... 88 6.3.3 Experimental setup ....................................................................... 88 6.3.4 Monitoring of disease severity, harvest and analysis .................... 89 6.3.5 Statistical analysis ........................................................................ 89 III Table of Contents 6.4 Results ................................................................................................... 90 6.5 Discussion ............................................................................................ 94 6.6 Acknowledgements .............................................................................. 96 6.7 References ............................................................................................ 97 7 SUMMARY ........................................................... 101 8 DEUTSCHE KURZFASSUNG .................................. 104 8.1 Einleitung ............................................................................................ 104 8.2 Das Pathosystem Tomate – Alternaria solani .................................. 104 8.3 Induzierte Resistenz ........................................................................... 105 8.4 Symbiotische Pilze ............................................................................. 106 8.5 Methoden ...........................................................................................