Annual plant review: the plant hormone ethylene/ Michael T. Mcmanus

1 100 Years of Ethylene - A Personal View 1
Don Grierson
1.1 Introduction 1
1.2 Ethylene Biosynthesis 2
1.3 Ethylene perception and signalling 7
1.4 Differential responses to ethylene 9
1.5 Ethylene and development 10
1.6 Looking ahead 13
Acknowledgements 14
References 14
2 Early Events in the Ethylene Biosynthetic Pathway - Regulation
of the Pools of Methionine and S-Adenosylmethionine 19
Katlmriua Bilrstenbinder and Mnrgret Saiiter
2.1 Introduction 20
2.2 The metabolism of Met and SAM 22
2.3 Regulation of de novo Met synthesis 25
2.4 Regulation of the SAM pool 27
2.4.1 Regulation of SAMS genes by ethylene and of
SAM enzyme activity by protein-S-nitrosylation 29
2.5 The activated methyl cycle 30
2.6 The S-methylmethionine cycle 32
2.7 The methionine or Yang Cycle 35
2.7.1 The Yang cycle in relation to polyamine and
nicotianamine biosynthesis 39
2.7.2 Regulation of the Yang Cycle in relation to
ethylene synthesis 40
2.8 Conclusions 42
Acknowledgement 43
References 44
VII
viii 01 Contents
3 The Formation of ACC and Competition Between Polyamines
and Ethylene for SAM 53
Smadar Harpaz-Saad, Gyeong Mee Yoon, Autar K. Mattoo, and
Joseph J. Kieber
3.1 Introduction 53
3.2 Identification and characterization of ACC synthase
activity in plants 54
3.2.1 Historical overview 54
3.2.2 Purification and properties of the ACC synthase
protein 56
3.3 Analysis of ACC synthase at the transcriptional level 58
3.3.1 Molecular cloning of ACC synthase genes 58
3.3.2 Transcriptional regulation of the ACC synthase
gene family 59
3.4 Post-transcriptional regulation of ACS 62
3.4.1 Identification and characterization of interactions
with ETOl 62
3.4.2 Regulation of ACS degradation 64
3.5 Does ACC act as a signal? 65
3.6 Biosynthesis
and physiology of polyamines 67
3.6.1 SAM is a substrate for polyamines 67
3.6.2 Physiology of polyamine effects in vitro and in vivo 67
3.6.3 Concurrent biosynthesis of ethylene and
polyamines 70
3.6.4 Do plant cells invoke a homeostatic regulation of
SAM levels? 72
Acknowledgements 72
References 72
4 The Fate of ACC in Higher Plants 83
Sarah }. Dorling and Michael T. McManus
4.1 Introduction 83
4.2 History of the discovery of ACC oxidase as the
ethylene-forming
enzyme 84
4.2.1 Early characterization of ACC oxidase 84
4.2.2 Cloning of the ethylene-forming enzyme as an
indicator of enzyme activity 85
4.2.3 Initial biochemical demonstration of
ethylene-forming enzyme activity in vitro 86
4.3 Mechanism of the ACC oxidase-catalyzed reaction 86
4.3.1 Investigation of the ACO reaction mechanism 87
4.3.2 Metabolism of HCN 89
4.3.3 Evidence of the conjugation of ACC 91
4.4 Transcriptional regulation of ACC oxidase 92
4.4.1
ACO multi-gene families 92
4.4.2 Differential expression of members of ACO
multi-gene families in response to developmental
Contents El ix
and environmental stimuli 94
4.4.3 Transcriptional regulation of gene expression 96
4.4.4 Crosstalk between ethylene signalling elements
and ACO gene expression 97
4.5 Translational regulation of ACC oxidase 97
4.6 Evidence that ACC oxidase acts as a control point in
ethylene biosynthesis
4.6.1 Cell-specific expression of ACC oxidase 102
4.6.2 Differential expression of ACS and ACO genes 103
4.7 Evolutionary aspects of ACC oxidase 104
Acknowledgements ^05
References ^05
5 Perception of Ethylene by Plants - Ethylene Receptors 117
Brad M. Binder, Caren Chang and G. Eric Schaller
5.1 Historical overview
5.2 Subfamilies of ethylene receptors and their evolutionary
history
5.3 Ethylene binding
5.3.1 Requirements for a metal cofactor 123
5.3.2 Characterization of the ethylene-binding pocket
and signal transduction 124
5.4 Signal output from the receptors 126
5.5 Overlapping and non-overlapping roles for the receptor
isoforms in controlling various phenotypes 128
5.6 Post-translational regulation of the receptors 131
5.6.1 Clustering of receptors 131
562 Ethylene-mediated degradation of receptors 132
563 Regulatory role of REVERSION-TO-ETHYLENE
SENSITIVITY (RTE1)/GREEN-RIPE (GR) 133
5.6.4 Other proteins that interact with the ethylene
receptors 134
5.7 Conclusions and model 135
Acknowledgements 137
References 1^^
6 Ethylene Signalling: the CTRl Protein Kinase 147
Silin Zhong And Caren Chang
6.1 Introduction 1"^^
6.2 Discovery of CTRl, a negative regulator of ethylene signal
transduction 148
6.2.1 Isolation of the Arabidopsis CTRl mutant 148
6.2.2 CTRl mutant phenotypes in Arabidopsis 149
X n Contents
6.2.3 Placement of CTRl in the ethylene-response
pathway 150
6.3 CTRl Encodes a
serine/threonine protein kinase 151
6.3.1 Molecular cloning and sequence analysis of the
Arabidopsis CTRl gene 151
6.3.2 CTRl biochemical activity 152
6.4 The CTR2 gene family 153
6.4.1 The CTR multi-gene family in tomato 153
6.4.2 Functional roles of tomato CTR genes 153
6.4.3 Transcriptional regulation of CTR-like genes 155
6.5 Regulation of CTRl activity 156
6.5.1 Physical association of CTRl with ethylene
receptors 158
6.5.2 Membrane localization of CTRl 159
6.5.3 An inhibitory role for the CTRl N-terminus? 159
6.5.4 Other factors that potentially interact with and
regulate CTRl activity 160
6.6 Elusive targets of CTRl signalling 161
6.7 CTRl crosstalk and interactions with other signals 162
6.8 Conclusions 163
Acknowledgements 164
References 164
7 EIN2 and EIN3 in Ethylene Signalling 169
Young-HeeCho, Sangho Lee and Snug-Dong Yoo
7.1 Introduction 169
7.2 Overview of ethylene signalling and EIN2 and EIN3 172
7.3 Genetic identification and biochemical regulation of EIN2 173
7.4 EIN3 regulation in ethylene signalling 174
7.4.1 Genetic identification
and biochemical regulation
ofEIN3 174
7.4.2 Structural and functional analysis of ein3 function 178
7.4.3 Function of EIN3 as transcription activator 180
7.5 Functions of ERPl and other ERFs in ethylene signalling 181
7.6 Future directions 183
Acknowledgements 184
References 184
8 Ethylene in Seed Development, Dormancy and Germination 189
Reimta Bogatekand Agnieszka Gniazdoivska
8.1 Introduction 189
8.2 Ethylene in seed embryogenesis 192
8.2.1 Ethylene biosynthesis
during zygotic
embryogenesis 192
Contents • xi
8.2.2 Ethylene involvement in the regulation of seed
morphology 194
8.3 Ethylene in seed
dormancy and germination 194
8.3.1 Ethylene biosynthesis
during dormancy release
and germination 194
8.3.2 The role of ethylene in seed heterogeneity 199
8.4 Ethylene interactions with other plant hormones in the
regulation of seed dormancy and germination 199
8.5 Ethylene interactions with ROS in the regulation of seed
dormancy and germination 202
8.6 Ethylene interactions with other small gaseous signalling
molecules (NO, HCN) in the regulation of seed dormancy
and germination 204
8.7 Concluding remarks . 207
Acknowledgements 209
References 209
9 The Role of Ethylene in Plant Growth and Development 219
Filip Vandenbiissche and Dotiiinique Van Der Straeten
9.1 Introduction 219
9.2 Design of root architecture 220
9.3 Regulation of hypocotyl growth 225
9.4 Shoot architecture and orientation: post-seedling growth 229
9.4.1 Inhibition of growth by ethylene 229
9.4.2 Stimulation of growth by ethylene 229
9.4.3 Shoot gravitropism 231
9.4.4 Control of stomatal density and aperture 231
9.4.5 Activity of the
shoot apical meristem 231
9.5 Floral transition 232
9.6 Determination of sexual forms of flowers 232
9.7 Ethylene effects on growth controlling mechanisms 233
9.8 Conclusions 234
Acknowledgements 234
References 234
10 Ethylene and Cell Separation Processes 243
Zinnia H. Gonzalez-Carranza vnd Jeremy A. Roberts
10.1 Introduction 243
10.2 Overview of the cell separation process 244
10.2.1 Abscission 245
10.2.2 Dehiscence 249
10.2.3 Aerenchyma formation 251
10.2.4 Stomata development and hydathode formation 252
10.2.5 Root cap cell sloughing and lateral root emergence 254
10.2.6 Xylem differentiation 257
xii • Contents
10.3 Transcription analyses during cell separation 258
10.4 Relationship between ethyiene and other hormones in the
regulation of cell separation 259
10.4.1 Ethyene and lAA 259
10.4.2 Ethyiene and jasmonic acid 260
10.4.3 Ethyiene and abscisic acid 261
10.5 Ethyiene and signalling systems during cell separation 261
10.5.1 Role of IDA, IDA-like, HAESA and HAESA-like
genes 261
10.5.2 MAP kinases 262
10.5.3 Nevershed 262
10.6 Application of knowledge of abscission to crops of
horticultural and agricultural importance 262
10.7 Conclusions and future perspectives 263
References 265
11 Ethyiene and Fruit Ripening 275
Jean-Claude Pech, Ediiardo Purgatto, Mondher Bouzaxjen and
Alain Latche
11.1 Introduction 276
11.2 Regulation of ethyiene production during ripening of
climacteric fruit 276
11.2.1 Regulation of ethyiene biosynthesis genes during
the System 1 to System2 transition 277
11.2.2 ACS genealleles are major determinants of
ethyiene biosynthesis and shelf-life of climacteric
fruit 280
11.2.3 Geneticdeterminism of the climacteric character 281
11.3 Transcriptional control of ethyiene biosjmthesis genes 282
11.4 Role of ethyienein ripening of non-climacteric fruit 283
11.5 Manipulation of ethyiene biosynthesis and ripening 284
11.6 Ethylene-dependent and -independent aspects of
climacteric ripening 286
11.7 Ethyiene perception and transduction effects in fruit
ripening ' 288
11.7.1 Ethyiene perception 288
11.7.2 Chemical control ofthe post-harvest ethyiene
response in fruit ripening 289
11.7.3 Ethyiene signal transduction 290
11.7.4 The transcriptional cascade leading to the
regulation of ethylene-responsiveand
ripening-related genes 291
11.8 Hormonal crosstalk in fruit ripening 292
11.8.1 Ethyiene and abscisic acid 293
Contents n xiii
11.8.2 Ethylene and jasmonate 293
11.8.3 Ethylene
and auxin 294
11.8.4 Ethylene and the gibberellins 295
11.9 Conclusions and future directions 295
Acknowledgements 296
References 296
12 Ethylene and Senescence Processes 305
Laura E. Graham,Jos H.M. Schippers, Paul
P. Dijkzvel and Carol
Wagstaff
12.1 Introduction 306
12.2 Overview of ethylene-mediated senescence in different
plant organs 306
12.2.1 Leaf senescence 306
12.2.2 Pod senescence 310
12.2.3 Petal senescence 312
12.3 Transcriptional regulation of ethylene-mediated
senescence processes 314
12.3.1 Global regulation 314
12.3.2 Transcription factors and signalling pathways 315
12.4 Interaction of ethylene with other hormones in relation to
senescence 323
12.5 The importance of ethylene-mediated senescence in
post-harvest biology 325
12.5.1 Post-harvest factors affected by ethylene 325
12.5.2 Ways of controlling ethylene-related post-harvest
losses 327
12.5.2.1 Packaging 327
12.5.2.2 1-Methylcyclopropene 328
12.6 Conclusions
and future perspectives 329
References 329
13 Ethylene: Multi-Tasker in Plant-Attacker Interactions 343
Sjoerd Van der Ent and CorneM.J. Pieterse
13.1 Introduction 344
13.2 Hormones in plant defence signalling 346
13.2.1 Hormones as defence regulators 346
13.2.2 Salicylic acid 347
13.2.3 Jasmonic acid 347
13.2.4 Ethylene 348
13.3 Implications of ethylene in basal defence and disease
susceptibility 348
13.3.1 Studies
with Arabidopsis thaliana 348
13.3.2 Studies with tobacco 350
xiv • Contents
13.3.3 Studies with tomato 351
13.3.4 Studies with soybean 352
13.3.5
Other plant species 352
13.4 Implications of ethylene in systemic immune responses 353
13.4.1 Systemic induced immunity 353
13.4.2 Rhizobacteria-mediated ISR 354
13.4.3 Genetic dissection of the ISR pathway in
Arabidopsis 356
13.4.4 Priming for enhanced JA/ethylene-dependent
defences 358
13.4.5 Molecular mechanisms of priming for enhanced
defence 360
13.4.6 Costs and benefits of priming for enhanced
defence 362
13.5 Ethylene modulates crosstalk among defence-signalling
pathways 362
13.5.1 Crosstalk in defence signalling 362
13.5.2 Interplay among SA,JA and ethylene signalling 363
13.5.3 Ethylene: an important modulator of
defence-signalling pathways 365
13.6 Concluding remarks 365
Acknowledgements 366
References 367
Index 379
First 8-page color plate section (between pages 168 and 169)
Second 8-page color plate section (between
pages 360 and 361)