Self-Incompatibility in Flowering Plants (eBook)

Preface 6
Contents 10
Contributors 17
Glossary 20
Evolution and Population Genetics of Self- Incompatibility 39
New Insights on Heterostyly: Comparative Biology, Ecology and Genetics 40
Abbreviations 40
1.1 Introduction 41
1.2 Comparative Biology and Evolutionary History of Heterostyly 43
1.2.1 Phylogeny Reconstruction and Character Evolution 44
1.3 Function and Reproductive Ecology of Heterostyly 47
1.3.1 Function of Heterostyly 47
1.3.2 Floral Morph Ratios and Reproductive Success 49
1.4 Inheritance of Heterostyly and the Supergene Model 51
1.4.1 Inheritance of Distyly and Tristyly 51
1.4.2 Supergene Model 52
1.4.3 Mutational Analyses and the Study of Genetic Variants 56
1.5 Molecular Genetics 56
1.5.1 Theoretical Models and Predictions 57
1.5.2 Protein Profiles 59
1.5.3 mRNA Expression 59
1.5.4 Genetic Localization 60
1.6 Concluding Remarks 62
References 63
Genetic and Environmental Causes and Evolutionary Consequences of Variations in Self- Fertility in Self Incompatible Species 70
Abbreviations 70
2.1 Introduction 71
2.2 Genetics of Self-Fertility 72
2.2.1 Mutations Affecting the S-locus 73
2.2.2 Unlinked Modifiers of SI 74
2.2.3 Plasticity in Self-Fertility 77
2.2.4 Summary of Genetics of Self-Fertility 78
2.3 Fate of Self-Fertility Genes 79
2.3.1 Conditions for Stable Polymorphisms 80
2.3.2 Summary and Conclusions Concerning Stable Polymorphisms 82
References 84
On the Evolutionary Modification of Self- Incompatibility: Implications of Partial Clonality for Allelic Diversity and Genealogical Structure 89
Abbreviations 89
3.1 Introduction 90
3.2 Mating System Dynamics 91
3.2.1 Relative Transition Rates 91
3.2.2 Multiple Origins of SC in Arabidopsis 91
3.2.3 Modified Forms of SI 92
3.3 S-Locus Evolution Under Partial Clonality 93
3.3.1 Diffusion Approximation 93
3.3.2 S-Allele Number and Frequency 96
3.3.3 Age of the Root 98
3.4 Discussion 101
3.4.1 Clonality in the Solanaceae 101
3.4.2 Evolutionary Stability of Partial SI 101
3.4.3 Paradoxical Effects on Mating Systems 102
3.5 Conclusions 103
Appendix 1: Diffusion Equation Approximation 104
Appendix 2: Simulations 105
References 105
Evolution and Phylogeny of Self-Incompatibility Systems in Angiosperms 108
Abbreviations 108
4.1 Introduction 109
4.1.1 Diversity of SI Systems in Angiosperms 110
4.1.2 Evolutionary Origin(s) of SI Systems 111
4.2 Was Self-Incompatibility Present in the First Angiosperms? 112
4.2.1 Self-Incompatibility in Basal Angiosperms 113
4.2.2 Self-Incompatibility in the Monocots 115
4.3 Phylogenetic Distribution of SI Systems 116
4.3.1 Late-Acting Ovarian Self Incompatibility (OSI) 119
4.3.2 Gametophytic Self-Incompatibility (GSI) 121
4.3.3 Sporophytic Self-Incompatibility (SSI) 123
4.4 The Relationship Between GSI and SSI 124
4.5 Discussion 126
References 130
What Genealogies of S-alleles Tell Us 137
Abbreviations 137
5.1 Introduction 138
5.2 Long-Term Demographic Information from the S-locus 139
5.3 Implications of Shared Ancestral Polymorphism 142
5.3.1 Tracing the History of Mating System Change 142
5.3.2 Diversification Rate Differences and Character State Reconstruction 144
5.4 The Pace of New Allele Formation 145
5.5 Remaining Issues of S-RNase Evolution 146
5.6 Pollen Specificity Genes 148
5.7 Conclusions 151
References 151
Self-Incompatibility and Evolution of Mating Systems in the Brassicaceae 156
Abbreviations 156
6.1 Introduction 157
6.2 Structural and Sequence Diversification of S-locus Haplotypes and Their Recognition Genes 158
6.2.1 Conserved and Diverged Features of the S-locus 160
6.2.2 Intra-Specific Structural Heteromorphism and Sequence Polymorphism: Suppressed Recombination and Maintenance of SRK- SCR Linkage 161
6.2.3 Diversification of the S-locus Genes and the SI Recognition Repertoire 163
6.3 Evolutionary Switches from Self-Incompatibility to Self- Fertility 168
6.3.1 Molecular Genetics of Switches to Self-Fertility 169
6.3.2 Breakdown of SI by Disruption of S-locus Gene Expression in Inter- Specific Hybrids 170
6.3.3 The Case of Self-Fertility in A. thaliana 171
6.4 Future Prospects 175
References 175
Molecular and Cell Biology of Self- Incompatibility Systems 181
Milestones Identifying Self-Incompatibility Genes in Brassica Species: From Old Stories to New Findings 182
Abbreviations 182
7.1 Self-Incompatibility as an Agriculturally Important Trait 183
7.2 The First Milestone: BatemanÌs Idea for Sporophytic Control of the S- locus 185
7.3 The Second Milestone: Identification of SLG by Using IEF 186
7.4 The Third Milestone: Identification of SRK, the Female S Determinant Gene 187
7.5 The Fourth Milestone: Functional Evidences of SRK in SI 188
7.6 The Fifth Milestone: Establishment of Bioassay System 189
7.7 The Sixth Milestone: Identification of SP11/SCR, the Male S Determinant Gene 190
7.8 After Identifying the SI Genes and Future Milestones 191
7.8.1 Demonstrating Physical Interaction Between SRK and SP11/ SCR 191
7.8.2 Downstream of the Interaction: Identifying Components and Mechanisms Involved in Mediating the Rejection of Self Pollen 193
7.8.3 Molecular Mechanisms of Dominance Relationships 194
7.8.4 Evolution of SI Genes 195
7.9 Prospects 196
References 197
"Self" Pollen Rejection Through the Intersection of Two Cellular Pathways in the Brassicaceae: Self- Incompatibility and the Compatible Pollen Response 204
Abbreviations 204
8.1 Introduction 205
8.2 The Early Stages of Compatible PollenÒStigma Interactions in the Brassicaceae 206
8.2.1 Pollen Capture and Adhesion 206
8.2.2 Pollen Hydration 207
8.2.3 Pollen Germination and Pollen Tube Penetration 209
8.3 The SI Response Causes Pollen Arrest at the Stigmatic Surface 210
8.3.1 The S Receptor Kinase Activates a Cellular Signalling Pathway in the Stigmatic Papilla to Trigger Self Pollen Rejection 210
8.3.2 The M Locus Protein Kinase acts Together with the S Receptor Kinase to Promote SI 211
8.3.3 The SRK Kinase Domain can Interact with a Range of Intracellular Proteins 212
8.3.4 Thioredoxin h Inhibits SRK Activity in the Absence of Self Pollen 213
8.3.5 ARC1 Functions Downstream of SRK to Promote SI 213
8.3.6 BnExo70A1 is a Potential Substrate for ARC1 and is Required for Compatible Pollen- Stigma Interactions 215
8.3.7 Endomembrane Changes in the Stigmatic Papillae Following Compatible and Self- Incompatible Pollinations in the Brassicaceae 216
8.4 Conclusions and Prospects 217
References 218
Molecular Biology of S-RNase-Based Self- Incompatibility 223
Abbreviations 223
9.1 Introduction 224
9.2 S-RNase Determines S-Specificity in Pistil 226
9.2.1 Isolation and Identification of S-RNase as the Pistil S 226
9.2.2 S-RNase Sequence Features and the Specificity Determinant 226
9.2.3 The Role of S-RNase: A Cytotoxin Specifically Inhibits Self Pollen 228
9.3 F-Box Proteins Determine S-Specificity in Pollen 229
9.3.1 Clues from Pollen-Part Self Compatible Mutants 229
9.3.2 Isolation of the Pollen SI Determinant, SLF/SFB 230
9.3.3 Sequence Analysis of SLFs and SFBs 231
9.3.4 Identification of SLF as the Pollen S 231
9.3.5 SFBs from Rosaceae Likely Represent Another Class of F- Box Genes 232
9.4 Other Genes That Modulate the SI Response 233
9.4.1 The Pistil Modifier Factors 233
9.4.2 The Pollen Modifier Factors 234
9.5 Molecular Mechanisms for S-RNase-based SI 235
9.5.1 Pollen S, the Positive or Negative Regulator of S-RNase? Clues from Genetic Evidence 235
9.5.2 The Fate of S-RNases: S-RNase Restriction is Likely to Involve Ubiquitination 236
9.5.3 Future Perspectives 238
References 240
Comparing Models for S-RNase-Based Self- Incompatibility 246
Abbreviations 246
10.1 The Biology of S-RNase-Based SI 247
10.1.1 Genetic Breakdown 247
10.2 S-RNase and S-locus F-box Proteins 248
10.2.1 S-RNase Structure and Specificity 248
10.2.2 S-locus F-Box Genes 250
10.3 Non-S-Specific Genes 251
10.3.1 HT Genes 252
10.3.2 S-RNase Binding Proteins in the Transmitting Tract Extracellular Matrix 253
10.3.3 Non-S-Specific Factors in Pollen 255
10.4 Comparing Models for S-RNase-Based SI 256
10.4.1 How do Compatible Pollen Tubes Resist S-RNaseCytotoxicity? 256
10.4.2 Is There a Separate Mechanism in the Rosaceae? 256
10.4.3 Inhibiting S-RNase Enzyme Activity 257
10.4.4 S-RNase Degradation 257
10.4.5 S-RNase Compartmentalisation 260
References 262
Self-Incompatibility in Papaver Rhoeas: Progress in Understanding Mechanisms Involved in Regulating Self- Incompatibility in Papaver 266
Abbreviations 266
11.1 Introduction 267
11.1.1 Genetics and Cell Biology of Self-Incompatibility in Papaver 267
11.1.2 How Studies on Self-Incompatibility in Papaver Started 268
11.1.3 The Papaver in Vitro SI System 270
11.2 S Proteins Determine S-Specificity in the Pistil 271
11.2.1 Identification of Pistil S-locus Components 271
11.2.2 Pistil S-Protein Sequence Information and Residues Required for Function 272
11.3 Identification of the Pollen S-Determinant 272
11.4 Mechanisms Involved in SI in the Papaver System 273
11.4.1 Calcium Signalling Mediates Papaver SI 273
11.4.2 A Role for Soluble Inorganic Pyrophosphatases (sPPases) in Papaver SI 274
11.4.3 Alterations to the Actin Cytoskeleton are Triggered by Papaver SI 275
11.4.4 SI Triggers Programmed Cell Death 276
11.5 An Overall Model for Mechanisms Involved in Regulating SI in Papaver 280
11.5.1 A Contrast to the S-RNase System and Brassica SI Systems 282
11.6 Future Perspectives 283
References 284
Molecular Genetics of Sporophytic Self- Incompatibility in Ipomoea, aMember of the Convolvulaceae 288
Abbreviations 288
12.1 Introduction 289
12.2 Sexual Reproduction in the Genus Ipomoea 290
12.3 Genetics of Self-Incompatibility in Ipomoea 290
12.4 Stigma-Specific Proteins 292
12.5 Physical Size of the S-locus 293
12.6 Genomic Organisation of the S-locus 295
12.7 S-locus Genes in Ipomoea 297
12.8 Diversity of the SI Systems 299
References 300
Self-Incompatibility in the Grasses 304
Abbreviations 304
13.1 Introduction 305
13.2 Genetic Control of SI in the Grasses 306
13.2.1 Features of the S-Z System 307
13.2.2 The Third Locus "T" 308
13.2.3 Mechanism of Action of S- and Z-Gene Products 309
13.3 Approaches and Progress in Cloning S and Z 309
13.3.1 Reverse Genetics 310
13.3.2 Forward Genetics 310
13.4 Conclusions 313
References 314
Heteromorphic Self-Incompatibility in Primula: Twenty- First Century Tools Promise to Unravel a Classic Nineteenth Century Model System 317
Abbreviations 317
14.1 Introduction 318
14.2 Floral Characteristics of the Mating Types of Primula 319
14.2.1 Style 320
14.2.2 Stigma 320
14.2.3 Corolla Mouth Size 320
14.2.4 Anthers 321
14.2.5 Pollen 321
14.2.6 Self-Incompatibility Specificity 321
14.3 Functions of Heteromorphic Characters 321
14.4 Physiological Nature of SI 323
14.4.1 Site of Operation 323
14.4.2 Candidate Molecules in the Operation of Heteromorphic SI 325
14.5 The Primula S-locus 325
14.5.1 Genetic Structure 325
14.5.2 Location and Size of the S-locus 329
14.5.3 Allelic Dominance 329
14.6 Floral Development 330
14.7 Molecular Genetic Characterisation of the Primula S-locus: Current Status 331
14.8 Conclusions and Future Prospects 333
References 334
Index 337