1;Foreword;5 1.1;References;8 2;Preface;9 3;Preface;11 4;Preface to the First Edition;13 5;Contents;15 6;Contributors;19 7;Part I of the Art;33 7.1;Mycorrhizal Fungi: What We Know and What Should We Know?;34 7.1.1;1 Introduction;34 7.1.2;2 Origin and Evolution of Mycorrhizal Studies;36 7.1.3;3 Development of AM Fungi;38 7.1.4;4 Beneficial Effects of AM Fungi;39 7.1.5;5 Mycorrhiza as Biological Agents;43 7.1.6;6 Factors Affecting the Symbiosis;45 7.1.7;7 Mycorrhizal Host Specificity and Seasonality;48 7.1.8;8 Ecological Significance of AMF Diversity: Inter- and Intraspecies Variations;49 7.1.9;References;49 7.2;Diversity, Function and Potential Applications of the Root- Associated Endophytes;60 7.2.1;1 Diversity of Fungal Root Endophytes;60 7.2.2;2 The Shortgrass Steppe: A Case Study of Fungal Root Endophyte Diversity and Function;61 7.2.3;3 Functions of Root Endophytes;66 7.2.4;4 Potential Applications of Root-Associated Endophytes;80 7.2.5;5 Conclusions;84 7.2.6;References;85 7.3;Structure, Extent and Functional Significance of Belowground Arbuscular Mycorrhizal Networks;90 7.3.1;1 Introduction;90 7.3.2;2 Spore Germination and Structure of Pre-symbiotic Mycelium;91 7.3.3;3 Evidence for Nonself-incompatibility in Pre-symbiotic Mycelial Networks;94 7.3.4;4 Visualization of Intact Mycorrhizal Networks Spreading from Roots Colonized by AM Fungi;97 7.3.5;5 Visualization of Belowground Interconnections Between Plants of Different Species, Genera and Families;98 7.3.6;References;100 7.4;Foraging for Resources in Arbuscular Mycorrhizal Fungi: What is an Obligate Symbiont Searching for and How is it Done?;104 7.4.1;1 Introduction;104 7.4.2;2 Resources for an Arbuscular Mycorrhizal Fungus;106 7.4.3;3 Foraging Activity;108 7.4.4;4 Testing Foraging Models in AMF;110 7.4.5;5 Main Challenges and New Approaches in Foraging Studies;115 7.4.6;6 Conclusions;116 7.4.7;References;116 7.5;Global Diversity Patterns of Arbuscular Mycorrhizal Fungi - Community Composition and Links with Functionality;120 7.5.1;1 Introduction;120 7.5.2;2 Taxon Diversity of AM Fungal Communities;121 7.5.3;3 Methodological Issues, Obstacles;126 7.5.4;4 Factors Shaping Communities of AM Fungi;130 7.5.5;5 Linking Taxonomic Diversity with Functionality;132 7.5.6;6 Conclusions;136 7.5.7;References;137 7.6;Mycorrhiza Helper Bacteria;144 7.6.1;1 Introduction;144 7.6.2;2 Helper Strains: Origin and Taxonomy;145 7.6.3;3 The Helper Mechanisms;146 7.6.4;4 Potential for Use of Mycorrhiza Helper Bacteria in Agri- and Silviculture;155 7.6.5;5 Perspectives;158 7.6.6;References;158 8;Part II Genetics and Molecular Biology;164 8.1;Genomic Organization and Mechanisms of Inheritance in Arbuscular Mycorrhizal Fungi: Contrasting the Evidence and Implications of Current Theories;166 8.1.1;1 Introduction;166 8.1.2;2 Mendelian versus Non-Mendelian Inheritance;167 8.1.3;3 AM Fungal Cells Harbor Many Nuclei and Many Genetic Variants;168 8.1.4;4 Alternative Hypotheses on Genomic Organization: The Evidence;168 8.1.5;5 Alternative Hypotheses on Genomic Organization: The Implications;173 8.1.6;6 A Model of Inheritance under Heterokaryosis;176 8.1.7;7 Conclusions;177 8.1.8;References;178 8.2;Ectomycorrhiza and Water Transport;180 8.2.1;1 Introduction;180 8.2.2;2 Impact of Soil Growing Hyphae on Plant Water Support;181 8.2.3;3 Ectomycorrhiza Formation Results in Modification of Plant Roots and Affects Their Water Transport Properties;181 8.2.4;4 Aquaporins: Gates for Symplastic Water Transport;182 8.2.5;5 Modulation of Plasma Membrane Water Transport Capacity in Poplar Fine Roots by Ectomycorrhiza Formation;183 8.2.6;6 Impacts of Ectomycorrhizas on Trees under Drought Conditions;185 8.2.7;7 Conclusions;186 8.2.8;References;187 8.3;Hypogeous Pezizaceae: Physiology and Molecular Genetics;192 8.3.1;1 Introduction;192 8.3.2;2 Unresolved Problems in the Life Cycle of Underground Pezizaceae;193 8.3.3;3 Factors Determining the Type of Mycorrhiza Formed;198 8.3.4;4 Genes Expressed in Fungus and Plant Prior t