Amoebae in the rhizosphere and their interactions with arbuscular mycorrhizal fungi [Elektronische Ressource] : effects on assimilate partitioning and nitrogen availability for plants / presented by Robert Koller

Academic Dissertation
accepted in fulfilment of the academic grade requirements of
Docteur en Sciences Agronomiques at the
Institut National Polytechnique de Lorraine
and
Doctor rerum naturalium at the
Technische Universität Darmstadt
Amoebae in the rhizosphere and their
interactions with arbuscular mycorrhizal
fungi: effects on assimilate partitioning and
nitrogen availability for plants
presented by
Dipl. Biol. Robert Koller
from Lippstadt
Reviewers Bryan Griffiths Professor, Teagasc Institute, Wexford
Christophe Salon Directeur de Recherche INRA, Dijon
Examiners Angelika Schwabe-Kratochwil Professor, TU-Darmstadt
Christophe Mougel Chargé de Recherche INRA, Dijon
Michael Bonkowski Professor, Universität zu Köln
Stefan Scheu Professor, TU-Darmstadt
Christophe Robin Chargé de Recherche INRA, Nancy

Date of thesis submission 25. September 2008
Date of public thesis defence 14. November 2008
Nancy Université Nancy & Technical University Darmstadt
Ecole Doctorale Sciences et Ingénierie Darmstadt 2009 Faculty of Biology
des Ressources Procédés Produits Institute for Zoology D17 Environnement
Ecole Nationale Supérieure d’Agronomie
et des Industries Alimentaires
Unité Mixte de Recherche INRA-INPL
Agronomie et Environnement Nancy
Colmar
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Table of contents
TABLE OF CONTENTS........................................................................................................................... 2
ABSTRACT................................................................................................................................................ 4
RÉSUMÉ..................................................................................................................................................... 5
ZUSAMMENFASSUNG ........................................................................................................................... 6
PUBLICATION LIST ............................................................................................................................... 7
PAPER PUBLISHED .................................................................................................................................... 7
PAPERS TO BE SUBMITTED........................................................................................................................ 7
ORAL COMMUNICATIONS ......................................................................................................................... 7
POSTERS.................... 8
CHAPTER I. INTRODUCTION.............................................................................................................. 9
I.1. REGULATION OF CARBON PARTITIONING IN THE PLANT AND RHIZODEPOSITION............................... 11
I.2. RHIZODEPOSITS: SOURCE OF ENERGY AND INFORMATION FOR MICROORGANISMS ........................... 12
I.3. PHOTOSYNTHATES ALLOCATION TOWARDS ROOT INFECTING AND FREE LIVING SYMBIONTS: AM
FUNGI AND PROTOZOA............................................................................................................................ 14
I.4. PROTOZOA - ARBUSCULAR MYCORRHIZAL FUNGI INTERACTIONS..................................................... 16
I.5. OBJECTIVES ..................................................................................................................................... 17
CHAPTER II. THE IMPACT OF PROTOZOA ON PLANT NITROGEN UPTAKE AND
MORPHOLOGY VARIES WITH PLANT SPECIES ......................................................................... 24
II.1. INTRODUCTION 25
II.2. MATERIALS AND METHODS............................................................................................................ 26
II.2.1. Plants, microcosms and incubation procedure ...................................................................... 26
II.2.2. Preparation of microcosms and soil ......................................................................................27
II.2.3. Inoculation with bacteria and protozoa ................................................................................. 28
II.2.4. Plant transfer and cultivation ................................................................................................ 28
II.2.5. Harvesting and analytical procedures ................................................................................... 29
II.2.6. Statistical analysis.................................................................................................................. 29
II.3. RESULTS.......... 30
II.3.1. Plant growth as affected by Acanthamoeba castellanii ......................................................... 30
II.4. DISCUSSION .................................................................................................................................... 33
II.4.1. Conclusions............................................................................................................................ 35
ACKNOWLEDEGMENTS........................................................................................................................... 36
REFERENCES........... 37
CHAPTER III. EFFECTS OF PROTOZOA ON PLANT NUTRITION AND CARBON
ALLOCATION DEPENDS ON THE QUALITY OF LITTER RESOURCES IN SOIL ................. 42
III.1. INTRODUCTION.............................................................................................................................. 43
III.2. MATERIAL AND METHODS 45
III.2.1. Microcosms............... 45
III.2.2. Plants and incubation conditions.......................................................................................... 46
15III.2.3. Preparation of N labelled plant litter................................................................................. 47
13III.2.4. CO pulse labelling of plants.............................................................................................. 47 2
III.2.5. Plant and soil analyses ......................................................................................................... 48
13 12 14 15III.2.6. Analysis of the C/ C and N/ N ratios of soil and plant samples.................................... 48
III.2.7. PLFA patterns and lipid stable isotope probing................................................................... 49
III.2.8. Counting of amoebae............................................................................................................ 50
III.2.9. Quantification of microbial N............................................................................................... 50
III.2.10. Statistical analyses.............................................................................................................. 51
III.3. RESULTS........................................................................................................................................ 52
III.3.1. Plant biomass, total C and N................................................................................................ 52
15 13III.3.2. Plant and microbial N and C enrichment........................................................................ 54
13III.3.3. C enrichment of plant organs ............................................................................................. 54
13III.3.4.chment of belowground respiration.......................................................................... 55
III.3.5. Phospholipid fatty acids........................................................................................................ 56
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13III.3.6. δ C signatures of PLFAs ..................................................................................................... 58
III.4. DISCUSSION................................................................................................................................... 59
III.4.1. Conclusions .......................................................................................................................... 61
ACKNOWLEDGEMENTS........................................................................................................................... 62
REFERENCES........... 63
CHAPTER IV. PROTOZOA (ACANTHAMOEBA CASTELLANII) AND ARBUSCULAR
MYCORRHIZAL FUNGI (GLOMUS INTRARADICES) MEDIATE THE PARTITIONING OF
CARBON AND THE AVAILABILITY OF NITROGEN FOR PLANTAGO LANCEOLATA...... 67
IV.1. INTRODUCTION.............................................................................................................................. 68
IV.2. MATERIAL AND METHODS ............................................................................................................ 69
IV.2.1. Microcosms, soil and microorganisms ................................................................................. 69
IV.2.2. Plant preparation and growth conditions............................................................................. 70
13 13IV.2.3. CO pulse labelling and quantification of C respiration of the belowground compartment2
.......................................................................................................................................................... 71
IV.2.4. Plant harvest and soil sampling............................................................................................ 72