Molecular plant pathology

Book Cover......Page 1
Half-Title......Page 2
Title......Page 3
Copyright......Page 4
Contents......Page 5
Abbreviations......Page 14
 1.1 The concept of plant disease......Page 19
  1.2.1 Fungi......Page 20
  1.2.4 Bacteria......Page 21
  1.2.5 Phytoplasmas and Spiroplasmas......Page 23
  1.2.6 Viruses......Page 25
  1.3.1 Historically important diseases......Page 26
  1.3.2 Emerging diseases......Page 30
 1.4 The control of plant diseases......Page 31
  1.5.2 The use of model organisms......Page 32
  1.5.3 Transformation techniques......Page 33
  1.5.4 Forward genetics......Page 35
  1.5.5 Reverse genetics......Page 42
  1.5.7 Gene expression profiling......Page 43
  1.5.8 Proteomics......Page 47
 References and further reading......Page 48
 2.2 Finding a suitable host......Page 50
 2.4 The germination process......Page 52
 2.5 Penetration methods......Page 53
 2.6 Germ-tube elongation......Page 56
  2.7.1 Physical factors......Page 57
  2.7.2 Chemical factors......Page 60
  2.8.1 Morphology......Page 61
  2.8.3 Melanisation......Page 63
  2.8.4 Turgor pressure......Page 65
 2.9 Cell-wall degrading enzymes (CWDEs)......Page 66
 References and further reading......Page 68
 3.1 The basic concepts—necrotrophy versus biotrophy......Page 69
  3.3.1 Quiescence......Page 70
  3.3.3 Detoxification of phytoalexins......Page 71
  3.3.4 ATP-binding cassette (ABC) transporters......Page 72
  3.3.5 Suppression of active oxygen species......Page 73
  3.3.6 Avoidance of recognition......Page 74
 3.5 Cell-wall-degrading enzymes......Page 75
 3.6 The role of toxins......Page 76
  3.6.1 Host-selective toxins......Page 77
  3.6.2 Host non-selective toxins......Page 80
  3.6.3 Mycotoxins......Page 81
  3.7.1 Haustorial structure......Page 84
  3.7.2 Haustorial function......Page 85
  3.8.1 The role of cytokinins......Page 87
  3.8.2 The role of polyamines......Page 88
 References and further reading......Page 89
 4.1 The concept of race structure......Page 91
  4.2.2 Cloning of avirulence genes......Page 92
  4.2.3 Avr protein structure and function......Page 94
 4.3 Fungicide resistance......Page 95
 4.4 Mechanisms for generating genetic variation in fungi......Page 97
 4.5 Mating-type genes......Page 98
 4.6 Chromosome instability......Page 99
 4.7 Alien genes/horizontal gene transfer......Page 101
 4.9 Role of heterokaryosis......Page 105
 4.11 Role of mycoviruses......Page 106
 References and further reading......Page 107
 5.1 Bacterial-bacterial communication—quorum sensing......Page 110
  5.2.1 Foliar bacteria......Page 112
  5.2.2 Soil-borne bacteria......Page 113
 5.3 Attachment......Page 114
 5.4 Stimulation of gene expression in response to host factors......Page 116
 5.5 The role of cell-wall-degrading enzymes (CWDEs)......Page 117
 5.6 The role of toxins......Page 119
 5.7 The role of hormones......Page 123
 5.8 The role of extracellular polysaccharides (EPSs)......Page 128
 References and further reading......Page 130
 6.2 The products of avirulence genes......Page 131
 6.3 Type III secretion mechanisms......Page 132
 6.5 Hrp-pili......Page 134
 6.6 Regulation of hrp genes......Page 135
 6.7 Secreted proteins......Page 139
 6.8 Secretion signals......Page 140
 6.10 The role of plasmids......Page 141
 References and further reading......Page 142
 7.1 The structure of plant viruses......Page 143
 7.3 Translation and replication of positive-strand RNA viruses......Page 144
  7.3.1 The production of sub-genomic RNAs and virus replication......Page 145
  7.3.3 Polyprotein processing......Page 149
  7.3.4 Readthrough and frameshifting......Page 150
 7.4 Negative-strand RNA viruses......Page 152
 7.6 Single-strand DNA viruses......Page 153
 7.7 Double-strand DNA viruses......Page 155
 7.9 Other sub-viral entities......Page 157
  7.10.1 Assembly of rod-shaped viruses......Page 159
  7.10.3 Assembly of membrane-bound particles......Page 160
 References and further reading......Page 161
 8.1 Transmission of viruses......Page 163
 8.2 Transmission by insect vectors......Page 164
 8.4 Transmission by zoosporic ‘fungi’......Page 166
 8.6 Short-distance movement of viruses in plants......Page 167
 8.7 Long-distance movement in plants......Page 170
  8.8.1 Alterations in host gene expression......Page 171
  8.8.2 Alterations in host cell metabolism......Page 172
  8.8.3 Suppression of defence responses......Page 173
 8.10 Genomic variation in plant viruses......Page 176
 References and further reading......Page 177
 9.1 Classical concepts of resistance......Page 178
  9.2.2 Root border cells......Page 180
 9.3 Induced defences......Page 181
  9.3.3 Induced structural barriers......Page 182
  9.3.4 Phytoalexins......Page 183
  9.3.5 Pathogenesis-related proteins......Page 187
  9.3.7 Post-transcriptional gene silencing (PTGS)......Page 189
 9.4 Systemic resistance mechanisms......Page 190
 9.5 ‘Communal’ resistance......Page 191
 References and further reading......Page 192
10 Resistance genes......Page 193
 10.2 Features of cloned resistance genes......Page 195
  10.3.1 Leucine-rich repeats (LRRs)......Page 198
  10.3.2 Cellular location of recognition......Page 200
  10.3.3 Does the R gene interact directly with the pathogen elicitor?......Page 201
 10.4 The TIR domain......Page 202
  10.6.2 Coiled coil (leucine zipper) domains......Page 203
 10.7 Genetic organisation of resistance genes......Page 204
 10.8 Mechanisms for generating new R gene specificities......Page 205
 10.9 Coevolution of resistance genes......Page 207
 10.10 Recessive resistance genes......Page 208
 References and further reading......Page 209
 11.1 Genetic analyses......Page 211
 11.2 MAP kinases (MAPK)......Page 213
 11.3 Ion fluxes and calcium homeostasis......Page 216
 11.4 The oxidative burst......Page 218
 11.5 Nitric oxide (NO)......Page 221
 11.6 (p)ppGpp signalling......Page 223
 11.7 Low-molecular-weight signalling molecules......Page 224
 11.9 Co-ordination of cell death responses......Page 227
 11.10.1 The EDS1 and NDR1 pathways......Page 229
  11.10.2 The role of NPR1......Page 230
  11.10.3 Pathways that are independent of NPR1......Page 232
 References and further reading......Page 233
 12.1 Classical approaches......Page 235
 12.2 The use of antibodies......Page 236
  12.2.2 Monoclonal antibodies (Mabs)......Page 237
  12.2.3 Recombinant DNA techniques......Page 238
  12.3.2 Lateral flow techniques......Page 240
  12.3.3 Other uses of antibodies......Page 242
  12.4.1 Identification of pathogen-specific markers......Page 243
  12.4.3 PCR-based techniques......Page 244
  12.4.5 Quantitative PCR......Page 246
 12.5 Phylogenetic analysis......Page 247
 References and further reading......Page 248
  13.1.1 The basis of resistance breeding programmes......Page 249
  13.1.2 The conventional breeding strategy......Page 250
 13.2 The use of tissue culture in plant breeding......Page 251
 13.3 Marker-assisted breeding......Page 252
 13.4 The identification of novel resistance gene specificities......Page 253
 13.5 The use of chemicals for disease control......Page 255
 13.6 The use of molecular biology in agrochemical production......Page 256
 13.7 Engineering chemicals that elicit defence responses in plants......Page 257
 References and further reading......Page 258
  14.1.1 Coat-protein-mediated resistance......Page 259
  14.1.2 Replicase-mediated resistance......Page 260
  14.1.4 RNA-mediated resistance......Page 261
 14.2 Plantibodies......Page 262
 14.3 Over-expressing defence genes......Page 263
 14.4 Expressing defence genes under the control of inducible promoters......Page 265
 14.5 The use of cloned resistance genes......Page 266
 14.6 Engineering broad-spectrum resistance......Page 267
 14.7 Resistance based on antagonistic microbes......Page 270
 14.8 Expression of vaccines in plants......Page 273
 References and further reading......Page 274
Index......Page 276