Bacteria in Agrobiology: Crop Ecosystems (eBook)

Preface 6
Contents 8
Contributors 10
Chapter 1: Emerging Role of Plant Growth Promoting Rhizobacteria in Agrobiology 14
1.1 Introduction 14
1.2 Soil and Rhizosphere in Sustainable Agriculture 15
1.3 Beneficial Bacteria 16
1.4 Crop Ecosystem 21
1.5 PGPR in Agrobiology 22
1.5.1 Cereals 22
1.5.2 Oilseeds 24
1.5.3 Fruits, Vegetables, and Cash Crops 26
1.5.4 Legumes 28
1.5.5 Forestry 31
1.5.6 Mulberry (Sericulture) 33
1.6 Limitations Associated with PGPR 34
1.7 Conclusion and Future Prospects 35
References 36
Chapter 2: Bacillus as PGPR in Crop Ecosystem 50
2.1 Introduction 50
2.2 Ecology of Bacillus and Paenibacillus Species 52
2.2.1 Distribution, Diversity, and Population Dynamics 52
2.2.2 Spatiotemporal Aspects 54
2.2.3 Rhizospheric Effect and Host Specificity 55
2.2.4 Endophytic Colonization and Plant Growth Promotion 57
2.3 Phtyostimulation and Biofertilization Effects 58
2.3.1 Phytostimulation 58
2.3.2 Biofertilization 59
2.4 Biological Control: Gram-Positive Perspectives 60
2.4.1 Success Stories of Bacillus Species as Biocontrol Agents 61
2.4.1.1 Antibiosis 62
2.4.1.2 Quorum Quenching and Biological Control 62
2.4.1.3 Induced Systemic Resistance: Ecological Significance and Applicability 64
2.4.1.4 Greenhouse Studies on Induction of Plant Resistance Systems 64
2.4.1.5 Field Experiments for Protection Against Systemic Disease 65
2.5 Conclusions 66
References 67
Chapter 3: Endophytic Bacteria: Perspectives and Applications in Agricultural Crop Production 73
3.1 Introduction 73
3.2 ``Endophytes´´ What It Means? 74
3.3 Sources of Endophytic Bacteria 75
3.4 Modes of Entry of Endophytes 75
3.5 Endophytic Movement Inside the Plant 79
3.6 Endophytic Colonization in Plant Tissues 79
3.7 Ecology of Endophytic Bacteria 81
3.8 Endophytes and Their Role in Plants 82
3.9 Beneficial Effects on Plant 84
3.10 Endophytic Diazotrophs 84
3.11 Endophyte´s Physiological Role 87
3.12 Biotization 88
3.13 Biological Control 91
3.14 Rice Endophytes 92
3.15 Sugarcane Endophyte 94
3.16 Conclusion 98
References 99
Chapter 4: PGPR Interplay with Rhizosphere Communities and Effect on Plant Growth and Health 109
4.1 Introduction 109
4.2 Interplay with Eukaryotic Hosts: The Human Pathogenic Potential of PGPR 110
4.3 The Rhizosphere as Reservoir for Potential Human Pathogenic Bacteria 111
4.4 Caenorhabditis elegans: A Model to Assess Potential Human Pathogenic Bacteria 112
4.5 Interplay with Rhizosphere Communities: The Impact on the Environment 115
4.6 Conclusions 118
References 118
Chapter 5: Impact of Spatial Heterogeneity Within Spermosphere and Rhizosphere Environments on Performance of Bacterial Biological Control Agents 122
5.1 Introduction 122
5.2 The Spermosphere and Rhizosphere Influence Behavior of Bacterial Biological Control Agents 123
5.3 Soil Factors Influence Biological Control Agents in the Spermosphere and Rhizosphere 124
5.3.1 Plants Influence the Complexity and Heterogeneity of the Spermosphere and Rhizosphere 125
5.3.1.1 Plant Inputs Serve as Nutrients and Influence the Behavior of Biological Control Bacteria 126
5.3.1.2 The Distribution and Bioavailability of Nutrient Compounds to Bacterial Biological Control Agents Are Nonuniform in the Spermosphere and Rhizosphere 130
5.3.1.3 Molecules Released by Plants into the Spermosphere and Rhizosphere Can Have Detrimental Effects on Residing Microorganisms, Including Biological Control Bacteria 132
5.3.1.4 Indigenous Microbial Communities Are Distributed Nonuniformly in the Spermosphere and Rhizosphere 132
5.3.1.5 Biological Control Agents Must Colonize the Rhizosphere for Effective Disease Suppression to Occur 133
5.4 Conclusion 134
References 135
Chapter 6: Biocontrol Mechanisms Employed by PGPR and Strategies of Microbial Antagonists in Disease Control on the Postharvest Environment of Fruits 142
6.1 Introduction 142
6.2 Biocontrol Strategies of PGPR of the Rhizosphere and of Antagonists in the Postharvest Environment 147
6.2.1 The Philosophy of Biocontrol 147
6.2.2 Antagonist Candidates in the Postharvest Environment 148
6.2.3 Diverse Mechanisms of Action 150
6.3 The Role of Host Plant in Biocontrol of Pathogens 154
6.3.1 Strategies of Defense by Host Plants 154
6.3.2 Signal Transduction and Genetic Involvement 155
6.4 Challenges in the Postharvest Environment 157
6.5 Ecology of the Microbial Environment 158
6.6 Nature and Role of Bacterial Antagonists 161
6.7 Application and Commercialization of Microbial Antagonists 164
6.8 Current Challenges in the Field of Biocontrol 164
6.9 Concluding Remarks 165
References 167
Chapter 7: Plant Growth-Promoting Bacteria Associated with Sugarcane 175
7.1 Introduction 175
7.2 Plant Growth-Promoting Rhizobacteria 176
7.2.1 Azospirillum 176
7.2.2 Azotobacter 180
7.2.3 Beijerinckia 180
7.2.4 Burkholderia 181
7.2.5 Enterobacter, Klebsiella, and Pantoea 182
7.2.6 Gluconacetobacter 182
7.2.7 Herbaspirillum 183
7.2.8 Pseudomonas 184
7.2.9 Other Bacteria 185
7.3 Role of PGPR in Sugarcane Growth 185
7.3.1 Biological Nitrogen Fixation and Phytohormones 186
7.3.2 Biocontrol Agent 188
7.4 Conclusion 191
References 192
Chapter 8: Use of Plant Growth Promoting Rhizobacteria in Horticultural Crops 198
8.1 Introduction 198
8.2 Modes of Action 199
8.2.1 Direct Plant Growth Promotion 200
8.2.1.1 Biological Nitrogen Fixation 200
8.2.1.2 Phytohormones Production or Inhibition of Ethylene 201
8.2.1.3 Solubilization of P and Enhanced Nutrient Uptake 202
8.2.2 Indirect Plant Growth Promotion 204
8.3 Application of PGPR in Horticulture 205
8.3.1 Effects on Vegetative Propagation of Fruit Crops and Grapes 206
8.3.2 Effects on Growth and Development 210
8.3.2.1 Vegetable Crops 210
8.3.2.2 Fruit Crops 213
8.3.3 Enhance to Tolerance Under Abiotic Stress 215
8.3.4 Biocontrol 222
8.4 Conclusions and Future Prospects 229
References 230
Chapter 9: Commercial Potential of Microbial Inoculants for Sheath Blight Management and Yield Enhancement of Rice 245
9.1 Introduction 246
9.2 Symptomatology 247
9.3 Disease Cycle 247
9.4 Use of Microbial Inoculants 248
9.4.1 Mode of Delivery 249
9.4.1.1 Seed Treatment 250
9.4.1.2 Seedling Dip 250
9.4.1.3 Soil Application 251
9.4.1.4 Foliar Application 251
9.4.1.5 Multiple Delivery Systems 252
9.4.2 Formulations 252
9.4.3 Shelf life 253
9.4.4 Root Colonization 253
9.5 Sheath Blight Management 255
9.5.1 Screening of Different PGPR Against ShB Pathogen and Seedling Growth Promotion Under Laboratory Conditions 256
9.5.2 Efficacy of Integral 257
9.5.2.1 In-Vitro Inhibition of ShB Pathogen 258
9.5.2.2 Rice Plant Growth Promotion 260
9.5.2.3 Chemical Compatibility 260
9.5.2.4 Efficacy of PGPR Against ShB Under Greenhouse and Field Conditions 262
9.6 Conclusions 265
References 266
Chapter 10: Beneficial Endophytic Rhizobia as Biofertilizer Inoculants for Rice and the Spatial Ecology of This Bacteria–Plant Association 273
10.1 Introduction 273
10.2 Can Biofertilization Help Recover a Deteriorating Global Environment? 275
10.3 Rice and Biofertilization 276
10.4 Justification of the Transitional Research and Technology Program 276
10.5 The Transitional Route Between Research and Technology 279
10.6 Methodology for Field Inoculation Experiments 280
10.6.1 Rice Varieties 280
10.6.2 Bacterial Test Strains and Preparation of Inoculants 282
10.6.3 Field Inoculation Trials 282
10.7 A ``Live and in Full Color´´ Recognition of the Biofertilization Contribution to Rice Performance 283
10.7.1 Contribution of Biofertilization in Salt-Affected Fields 286
10.7.2 Comparison Between Outcomes of Researcher´s and Farmer´s Rice Farming Managements 287
10.7.3 Rice Straw, a Debit or Credit to National Economy and Environmental Soundness 288
10.7.4 Plant Growth Tendencies as Affected by Biofertilization 289
10.7.5 Inoculation and N Economy in the Rice Agroecosystem 290
10.8 Comparisons of Rhizobia with Other Biofertilizer Candidates for Rice 292
10.9 Biosafety, a Pertinent Issue in the Biofertilization Technology 293
10.10 Conclusions and Recommendations Derived from Field Inoculation Studies 293
10.11 Spatial Ecology of Rice-Rhizobia Interactions 294
10.11.1 Distribution of a Candidate Rhizobial Inoculant Strain in Rice-Cultivation Fields in Egypt 294
10.11.2 Spatial Analysis of Rhizobial Colonization on Rice Roots 296
10.12 Concluding Statements 298
References 299
Chapter 11: Plant Growth-Promoting Bacteria: Fundamentals and Exploitation 303
11.1 Introduction 303
11.2 Organisms in the Rhizosphere 304
11.3 Nutrients in the Rhizosphere 305
11.4 Root Colonization 306
11.4.1 Recently Developed Technologies for Studying Interactions in the Rhizosphere 306
11.4.2 Autofluorescent Proteins (AFPs) 307
11.4.3 Colonization Genes and Traits 310
11.5 Bacteria Which Can Promote Plant Growth Directly 314
11.5.1 Introduction 314
11.5.2 Biofertilizers 314
11.5.3 Rhizoremediators 315
11.5.4 Phytostimulators/Plant Growth Promoters 316
11.5.4.1 Auxins 319
11.5.4.2 Cytokinins 320
11.5.4.3 Gibberellins (GAs) 321
11.5.5 Stress Controllers 321
11.5.5.1 Abscisic Acid (ABA) 322
11.5.5.2 Ethylene (ET) 322
11.6 Bacteria Which Can Control Plant Diseases 322
11.6.1 Introduction to Biocontrol Microbes 323
11.6.2 Mechanisms of Biocontrol 323
11.6.2.1 Antibiosis 323
11.6.2.2 Predation and Parasitism 325
11.6.2.3 Competition for Nutrients and Niches 325
11.6.2.4 Induced Systemic Resistance 326
11.6.2.5 Signal Interference 326
11.6.3 Role of Root Colonization in Biocontrol Mechanisms 327
11.6.4 Mycelium Colonization by Bacteria 328
11.6.5 Resistance of the Pathogen Toward Biocontrol Agents 330
11.7 From Laboratory to Industrial Application 331
11.7.1 Introduction 331
11.7.2 Evaluation of Opportunities 332
11.7.3 Industry Takes over 332
11.7.4 Industrial Research 333
11.7.5 Strain Safety 333
11.7.6 Large-Scale Production and Formulation 334
11.7.7 Registration in the EU: Legal Basis and Requirements 335
11.7.8 Intellectual Property Rights and Patenting 337
11.7.9 Marketing 337
11.7.10 Integrated Pest Management (IPM) 338
11.8 Lessons from the Past to Create a Shining Future 338
References 340
Chapter 12: PGPR in Coniferous Trees 352
12.1 Introduction 352
12.2 Economic, Environmental, and Cultural Aspects of Conifers 354
12.3 Mechanisms of PGPR in Conifers 356
12.3.1 Direct Mechanisms 356
12.3.2 Indirect Mechanisms 359
12.4 Conclusions and Perspectives for the Future 363
References 365
Chapter 13: Perspectives of PGPR in Agri-Ecosystems 367
13.1 Introduction 367
13.2 Rhizospheric Biodiversity 368
13.3 Mechanisms of Plant Growth Promotion 369
13.3.1 Nitrogen Fixation 369
13.3.2 Phosphate Solubilization 371
13.3.3 Siderophore Production 374
13.3.3.1 Synthesis 374
13.3.3.2 Uptake 376
13.3.4 Phytohormone Production 377
13.3.4.1 Auxin 377
13.3.4.2 Gibberellin 377
13.3.4.3 Cytokinin 378
13.3.4.4 Ethylene 378
13.3.4.5 Abscisic Acid 378
13.4 Metabolites 379
13.4.1 Antibiotic Production and Regulation 379
13.4.2 Cyanide Production 380
13.4.3 Antifungal Activity 380
13.4.4 Elicitors 381
13.4.5 Biosurfactants 382
13.5 Exopolysaccharide 382
13.6 Production of Insecticide 382
13.7 Plant Responses to PGPR 383
13.8 Challenges and Future Prospects 383
References 385
Chapter 14: Ecofriendly Management of Charcoal Rot and Fusarium Wilt Diseases in Sesame (Sesamum indicum L.) 392
14.1 Present and Future Prospective of Sesame 392
14.2 Sesame Pathogens: Macrophomina phaseolina and Fusarium oxysporum f. sp. sesami 393
14.2.1 Charcoal Rot 394
14.2.2 Fusarium Wilt 394
14.3 Resistant Varieties of Sesame: An Effective Strategy for Disease Control 394
14.4 Fertilizers Versus Biofertilizers for Sustainable Approaches 395
14.4.1 Cost-effective and Eco-friendly Strategies as Sustainable Approaches 396
14.4.2 Biological Control of Charcoal Rot and Fusarium Wilt 398
14.4.2.1 Application of Phytostimulant and Biocontrol Agents 399
14.4.2.2 Integration of PGPR Amended with Chemical Fertilizers 399
14.4.2.3 Application of BioChemo-Formulations 400
14.4.2.4 Others 402
14.5 Conclusion 403
References 403
Chapter 15: Crop Health Improvement with Groundnut Associated Bacteria 411
15.1 Groundnut: An Economically Important Legume 411
15.2 Major Constraints of Groundnut Production 412
15.3 Major Diseases Affecting Groundnut Crop Health 413
15.4 Beneficial Microbes for Improved Health 416
15.5 Different Plant Parts as Sources of Beneficial Bacteria Affecting Crop Improvement 417
15.5.1 The Spermosphere 417
15.5.2 The Rhizosphere 418
15.5.3 The Phyllosphere 418
15.5.4 Endophytic Sites 419
15.6 Groundnut-Associated Beneficial Bacteria 419
15.6.1 Rhizobial Strains 419
15.6.2 PGPR Strains 420
15.6.2.1 Groundnut Crop as a Source of PGPR 420
15.6.2.2 Mechanisms Involved in Growth Promotion and Disease Control by PGPR 421
15.6.2.3 Direct Growth Promotion by Bacteria 423
15.6.2.4 Indirect Growth Promotion by Bacteria 424
15.6.2.5 Compatibility of Bacteria with Seed/Root exudates 426
15.7 Interaction of Rhizobial and PGPR Strains for Growth Improvement 427
15.8 Carrier-based Formulations for Growth Promotion by PGPR 428
15.9 Conclusions 429
References 429
Index 435