Ecology and evolution of the grass-endophyte symbiosis / Gregory P. Cheplick, Stanley H. Faeth.

Format:

Book

Author/Creator:

Cheplick, G. P. (Gregory Paul), 1957-

Contributor:

Faeth, Stanley H., 1951-

Language:

English

Subjects (All):

Endophytic fungi.

Grasses--Ecophysiology.

Grasses.

Plant-fungus relationships.

Endosymbiosis.

Physical Description:

ix, 241 pages : illustrations ; 25 cm

Place of Publication:

Oxford ; New York : Oxford University Press, 2009.

Summary:

Endophytic fungi are common and diverse in plants. Yet the nature of their interactions with host plants and how these interactions cascade upward to communities and ecosystems are largely unknown. In the first book of its kind, Gregory P. Cheplick and Stanley H. Faeth provide a synthesis of existing studies of endophyte-grass symbioses within the context of modern ecological and evolutionary concepts. The authors present a large body of research covering a range of topics including the effects of endophytes on host growth, physiology, reproduction, and competitive ability in a variety of grasses and environments. Clearly and engagingly written, this long-needed book highlights the most essential aspects of symbiosis ecology and evolution while suggesting avenues for significant future research.

Contents:

1 Introduction: The Grass-Endophyte Symbiosis 3

1.1 Endophytic fungi and grasses 4

1.2 Ecological, evolutionary, and economic significance of endophytes 8

1.3 Mutualism, parasitism, or commensalism? 13

1.4 Assessment of endophyte infections in host populations 15

2 Effects of Endophytes on Their Hosts 18

2.1 Host growth and reproduction 18

2.1.1 Eliminating the endophyte 19

2.1.2 Growth 21

2.1.3 Photosynthetic physiology 26

2.1.4 Reproduction 29

2.2 Abiotic stress tolerance 35

2.2.1 Drought 35

2.2.2 Minerals 39

2.2.3 Other stresses 42

2.3 Competitive ability 44

3 Endophytes and Host-Plant Herbivore Relationships 50

3.1 Endophytes as defensive mutualists 50

3.1.1 Alkaloids-the key to herbivore resistance? 51

3.2 Effects on vertebrates 53

3.2.1 Agronomic grasses 53

3.2.2 Wild grasses 54

3.3 Invertebrate herbivory 57

3.4 Causes for variability in herbivore resistance 59

3.5 Antimicrobial effects of endophytes and their alkaloids 62

3.6 Herbivory and grass competitive interactions 64

3.7 Why don't all endophyte-host grass combinations produce diverse, highly toxic alkaloids? 66

3.8 Endophytes and tolerance to herbivory 68

3.9 Above- and belowground microbial interactions and herbivory 70

3.10 Do some endophytes facilitate herbivory on their hosts? 71

4 Genotypic Specificity of Grass-Endophyte Interactions 75

4.1 Host genotypes and interactions with endophytes 78

4.1.1 Agronomic grasses 79

4.1.2 Native grasses 82

4.2 Host phenotypic plasticity 83

4.3 Endophyte genotype 87

4.3.1 Haplotypes, strains, and races 88

4.3.2 Assessing endophyte genotypes 89

4.3.3 Effects of host growth and physiology 90

4.3.4 Genetic diversity 93

4.3.5 Host-adapted endophyte races 97

4.3.6 Multistrain infections and fungal hybridization 99

5 Evolutionary Ecology of Grass-Endophyte Interactions 102

5.1 Dynamics of host populations 102

5.1.1 Genet and ramet dynamics 104

5.1.2 A common garden experiment with perennial ryegrass 107

5.1.2.1 Tiller dynamics 107

5.1.2.2 The allometry of reproduction 110

5.1.2.3 Carbohydrate costs of endophyte infection 112

5.1.2.4 The cost of reproduction 113

5.1.3 Genotypic sorting by natural selection 115

5.2 Explaining the persistence and infection frequency of endophytes in grass populations 119

5.2.1 Explaining low infection frequencies when endophytes are mutualistic 128

5.2.2 Explaining high infection frequencies when endophytes are nonmutualistic or variable in their effects 129

5.3 Coevolution of endophyte and host populations 134

5.3.1 Hybridization complicates the phylogenetic (and ecological) picture 136

5.3.2 Coevolution and population-level interactions 139

5.3.2.1 Coevolution and population-level interactions in Epichloe 140

5.3.2.2 Coevolution and population-level interactions in Neotyphodium 141

6 Community and Ecosystem Consequences of Grass Endophytes 145

6.1 Endophytes within the context of community genetics 145

6.2 Community effects 146

6.2.1 Plant diversity 146

6.2.2 Herbivore and natural enemy abundance and diversity 149

6.2.3 Trophic interactions 152

6.2.4 Spatial heterogeneity of E+ and E- plants, herbivory, and trophic interactions 156

6.3 The paradox of endophyte-associated plant defenses 158

6.3.1 More interacting plant species, more variation in endophyte-host outcomes 161

6.4 Community and ecosystem effects 163

6.4.1 Invasibility and productivity 163

6.4.2 Community change-succession 165

6.4.3 Decomposition and nutrient cycling 166

7 Future Directions 169

7.1 New information and future research 169

7.1.1 Extensions to other grass-endophyte systems 169

7.1.2 Do endophytic fungi really matter? 172

7.1.3 Host biology 173

7.1.3.1 Host reproductive biology 176

7.1.4 Coevolutionary outcomes 178

7.1.5 Herbivory 180

7.1.6 Other interacting species and multitrophic interactions 182

7.1.7 The fungal perspective 183

7.1.8 Molecular ecology and evolution 184

7.2 Application of grass-endophyte research 185

7.2.1 Global environmental change 185

7.2.2 Ecology of invasive species 186

7.2.3 Ecological restoration 186

7.2.4 Emerging infectious disease 187

7.2.5 Agronomy and agroecosystems 189.

Notes:

Includes bibliographical references (pages 193-231) and index.

ISBN:

9780195308082

0195308085

OCLC:

227327743