Global Climate Change and Plant Stress Management

Mohammad Wahid Ansari is Assistant Professor in the Department of Botany, Zakir Hussain Delhi College, University of Delhi, India. He has researched and published widely on plant biology and stress tolerance.

Anil Kumar Singh is Principal Scientist at the Indian Council of Agricultural Research-National Institute for Plant Biotechnology, New Delhi, India. He has researched extensively into plant adaptations and environmental responses, as well as plant stress tolerance and related subjects.

Narendra Tuteja is Visiting Scientist at the International Centre for Genetic Engineering and Biotechnology, New Delhi, India. He has published extensively on plant stress tolerance, mango malformation and related subjects.

List of Contributors xvii

Foreword xxiii

Preface xxv

Author Biographies xxvii

Part 1 Views and Visions 1

1 Boosting Resilience of Global Crop Production Through Sustainable Stress Management 3
Rajeev K. Varshney and Abhishek Bohra

References 5

2 Sustaining Food Security Under Changing Stress Environment 7
Sudhir K. Sopory

References 8

3 Crop Improvement Under Climate Change 9
Shivendra Bajaj and Ratna Kumria

3.1 Crop Diversity to Mitigate Climate Change 10

3.2 Technology to Mitigate Climate Change 10

3.3 Farm Practices to Mitigate Climate Change 11

3.4 Conclusion 11

References 11

4 Reactive Nitrogen in Climate Change, Crop Stress, and Sustainable Agriculture: A Personal Journey 13
Nandula Raghuram

4.1 Introduction 13

4.2 Reactive Nitrogen in Climate Change, Agriculture, and Beyond 13

4.3 Nitrogen, Climate, and Planetary Boundaries of Sustainability 14

4.4 Emerging Global Response and India’s Leadership in It 14

4.5 Regional and Global Partnerships for Effective Interventions 15

4.6 Building Crop NUE Paradigm Amidst Growing Focus on Stress 16

4.7 From NUE Phenotype to Genotype in Rice 17

4.8 Furthering the Research and Policy Agenda 18

References 18

Part 2 Climate Change: Global Impact 23

5 Climate-Resilient Crops for CO 2 Rich-Warmer Environment: Opportunities and Challenges 25
Sayanta Kundu, Sudeshna Das, Satish K. Singh, Ratnesh K. Jha, and Rajeev Nayan Bahuguna

5.1 Introduction 25

5.2 Climate Change Trend and Abiotic Stress: Yield Losses Due to Major Climate Change Associated Stresses Heat, Drought and Their Combination 26

5.3 Update on Crop Improvement Strategies Under Changing Climate 27

5.3.1 Advances in Breeding and Genomics 27

5.3.2 Advances in Phenomics and High Throughput Platforms 28

5.3.3 Non-destructive Phenotyping to Exploit Untapped Potential of Natural Genetic Diversity 28

5.4 Exploiting Climate-Smart Cultivation Practices 29

5.5 CO 2 -Responsive C 3 Crops for Future Environment 30

5.6 Conclusion 31

References 31

6 Potential Push of Climate Change on Crop Production, Crop Adaptation, and Possible Strategies to Mitigate This 35
Narendra Kumar and SM Paul Khurana

6.1 Introduction 35

6.2 Influence of Climate Change on the Yield of Plants 36

6.3 Crop Adaptation in Mitigating Extreme Climatic Stresses 38

6.4 Factors That Limit Crop Development 39

6.5 Influence of Climate Change on Plants’ Morphobiochemical and Physiological Processes 39

6.6 Responses of Plant Hormones in Abiotic Stresses 40

6.7 Approaches to Combat Climate Changes 41

6.7.1 Cultural Methodologies 41

6.7.2 Conventional Techniques 41

6.7.3 Strategies Concerned with Genetics and Genomics 41

6.7.3.1 Omics-Led Breeding and Marker-Assisted Selection (MAS) 41

6.7.3.2 Genome-Wide Association Studies (GWAS) for Evaluating Stress Tolerance 42

6.7.3.3 Genome Selection (GS) Investigations for Crop Improvement 42

6.7.3.4 Genetic Engineering of Plants in Developing Stress Tolerance 43

6.7.4 Strategies of Genome Editing 43

6.7.5 Involvement of CRISPR/Cas 9 43

6.8 Conclusions 44

Conflict of Interest Statement 44

Acknowledgment 44

References 45

7 Agrifood and Climate Change: Impact, Mitigation, and Adaptation Strategies 53
Sudarshna Kumari and Gurdeep Bains

7.1 Introduction 53

7.2 Causes of Climate Change 54

7.2.1 Greenhouse Gases 54

7.2.2 Fossil Fuel Combustion 54

7.2.3 Deforestation 55

7.2.4 Agricultural Expansion 55

7.3 Impact of Climate Change on Agriculture 55

7.3.1 Crop Productivity 56

7.3.2 Disease Development 58

7.3.3 Plant Responses to Climate Change 58

7.3.4 Livestock 59

7.3.5 Agriculture Economy 59

7.4 Mitigation and Adaptation to Climate Change 60

7.4.1 Climate-Smart Cultural Practices 60

7.4.2 Climate-Smart Agriculture Technologies 60

7.4.3 Stress-Tolerant Varieties 61

7.4.4 Precision Management of Nutrients 61

7.4.5 Forestry and Agroforestry 61

7.5 Conclusions and Future Prospects 61

References 62

8 Dynamic Photosynthetic Apparatus in Plants Combats Climate Change 65
Ramwant Gupta and Ravinesh Rohit Prasad

8.1 Introduction 65

8.2 Climate Change and Photosynthetic Apparatus 66

8.3 Engineered Dynamic Photosynthetic Apparatus 66

8.4 Conclusion and Prospects 68

References 68

9 CRISPR/Cas Enables the Remodeling of Crops for Sustainable Climate-Smart Agriculture and Nutritional Security 71
Tanushri Kaul, Rachana Verma, Sonia Khan Sony, Jyotsna Bharti, Khaled Fathy Abdel Motelb, Arul Prakash Thangaraj, Rashmi Kaul, Mamta Nehra, and Murugesh Eswaran

9.1 Introduction: CRISPR/Cas Facilitated Remodeling of Crops 71

9.2 Impact of Climate Changes on Agriculture and Food Supply 72

9.3 Nutritionally Secure Climate-Smart Crops 73

9.4 Novel Game Changing Genome-Editing Approaches 74

9.4.1 Knockout-Based Approach 87

9.4.2 Knock-in-Based Approach 87

9.4.3 Activation or Repression-Based Approach 87

9.5 Genome Editing for Crop Enhancement: Ushering Towards Green Revolution 2.0 88

9.5.1 Mitigation of Abiotic Stress 88

9.5.2 Alleviation of Biotic Stress 89

9.5.3 Biofortification 89

9.6 Harnessing the Potential of NGS and ML for Crop Design Target 90

9.7 Does CRISPR/Cas Address the Snag of Genome Editing? 94

9.8 Edited Plant Code: Security Risk Assessment 95

9.9 Conclusion: Food Security on the Verge of Climate change 96

References 96

Part 3 Socioeconomic Aspects of Climate Change 113

10 Perspective of Evolution of the C 4 Plants to Develop Climate Designer C 4 Rice as a Strategy for Abiotic Stress Management 115
Shuvobrata Majumder, Karabi Datta, and Swapan K. Datta

10.1 Introduction 115

10.2 How Did Plants Evolve to the C 4 System? 117

10.2.1 Gene Amplification and Modification 117

10.2.2 Anatomical Preconditioning 117

10.2.3 Increase in Bundle Sheath Organelles 118

10.2.4 Glycine Shuttles and Photorespiratory CO 2 Pumps 118

10.2.5 Enhancement of PEPC and PPDK Activity in the Mesophyll Tissue 118

10.2.6 Integration of C 3 and C 4 Cycles 118

10.3 What Are the Advantages of C 4 Plants over C 3 Plants? 118

10.4 Molecular Engineering of C 4 Enzymes in Rice 119

10.4.1 Green Tissue-Specific Promoters 120

10.4.2 Expressing C 4 Enzyme, PEPC in Rice 120

10.4.3 Expressing C 4 Enzyme, PPDK in Rice 120

10.4.4 Expressing C 4 Enzyme, ME and NADP-ME in Rice 121

10.4.5 Expressing Multiple C 4 Enzymes in Rice 121

10.5 Application of CRISPR for Enhanced Photosynthesis 121

10.6 Single-Cell C 4 Species 121

10.7 Conclusion 122

Acknowledgments 122

References 122

11 Role of Legume Genetic Resources in Climate Resilience 125
Ruchi Bansal, Swati Priya, and H. K. Dikshit

11.1 Introduction 125

11.2 Legumes Under Abiotic Stress 126

11.2.1 Legumes Under Drought Stress 126

11.2.2 Legumes Under Waterlogging 126

11.2.3 Legumes Under Salinity Stress 127

11.2.4 Legumes Under Extreme Temperature 127

11.3 Genetic Resources for Legume Improvement 128

11.3.1 Lentil 129

11.3.2 Mungbean 130

11.3.3 Pigeon Pea 131

11.3.4 Chickpea 131

11.4 Conclusion 133

References 134

12 Oxygenic Photosynthesis – a Major Driver of Climate Change and Stress Tolerance 141
Baishnab C. Tripathy

12.1 Introduction 141

12.2 Evolution of Chlorophyll 141

12.3 The Great Oxygenation Event 142

12.4

Role of Forest in the Regulation of O 2 and CO 2 Concentrations in the Atmosphere 142

12.5 Evolution of C 4 Plants 142

12.6 The Impact of High Temperature 143

12.7 c 4 Plants Are Tolerant to Salt Stress 144

12.8 Converting C 3 Plants into C 4 – A Himalayan Challenge 145

12.9 Carbonic Anhydrase 145

12.10 Phosphoenolpyruvate Carboxylase 146

12.11 Malate Dehydrogenase 147

12.12 Decarboxylating Enzymes 147

12.12.1 NAD/NADP-Malic Enzyme 148

12.12.2 Phosphoenolpyruvate Carboxykinase 149

12.13 Pyruvate Orthophosphate Dikinase 149

12.14 Regulation of C 4 Photosynthetic Gene Expression 150

12.15 Use of C 3 Orthologs of C 4 Enzymes 151

12.16 Conclusions and Future Directions 151

Acknowledgment 152

References 152

13 Expand the Survival Limits of Crop Plants Under Cold Climate Region 161
Bhuvnesh Sareen and Rohit Joshi

13.1 Introduction 161

13.2 Physiology of Cold Stress Tolerant Plants 162

13.3 Stress Perception and Signaling 163

13.4 Plant Survival Mechanism 164

13.5 Engineering Cold Stress Tolerance 165

13.6 Future Directions 168

Acknowledgment 168

References 168

14 Arbuscular Mycorrhizal Fungi (AMF) and Climate-Smart Agriculture: Prospects and Challenges 175
Sharma Deepika, Vikrant Goswami, and David Kothamasi

14.1 Introduction 175

14.2 What Is Climate-Smart Agriculture? 176

14.3 AMF as a Tool to Practice Climate-Smart Agriculture 177

14.3.1 AMF in Increasing Productivity of Agricultural Systems 177

14.3.1.1 Plant Nutrition and Growth 177

14.3.1.2 Improved Soil Structure and Fertility 181

14.3.2 AMF-Induced Resilience in Crops to Climate Change 182

14.3.2.1 AMF and Salinity Stress 182

14.3.2.2 AMF and Drought Stress 183

14.3.2.3 AMF and Heat Stress 184

14.3.2.4 AMF and Cold Stress 184

14.3.3 AMF-Mediated Mitigation of Climate Change 186

14.3.4 Agricultural Practices and AMF Symbiosis – Crop Rotations, Tillage, and Agrochemicals 187

14.3.5 AMF Symbiosis and Climate Change 187

14.3.6 Conclusions and Future Perspectives 188

Acknowledgment 189

References 189

Part 4 Plant Stress Under Climate Change: Molecular Insights 201

15 Plant Stress and Climate Change: Molecular Insight 203
Anamika Roy , Mamun Mandal, Ganesh Kumar Agrawal, Randeep Rakwal, and Abhijit Sarkar

15.1 Introduction 203

15.2 Different Stress Factors and Climate Changes Effects in Plants 206

15.2.1 Water Stress 206

15.2.1.1 Drought 206

15.2.1.2 Flooding or Waterlogging 206

15.2.2 Temperature Stress 207

15.2.2.1 High Temperature Stress 207

15.2.2.2 Low Temperature Stress 207

15.2.3 Salinity Stress 207

15.2.4 Ultraviolet (UV) Radiation Stress 207

15.2.5 Heavy Metal Stress 207

15.2.6 Air Pollution Stress 208

15.2.7 Climate Change 208

15.3 Plant Responses Against Stress 208

15.3.1 Water Stress Responses 208

15.3.1.1 Drought Responses 208

15.3.1.2 Waterlogging Responses 210

15.3.2 Temperature Stress Responses 210

15.3.2.1 High Temperature Stress Responses 210

15.3.2.2 Low Temperature Stress Responses 211

15.3.3 Salinity Stress Responses 212

15.3.3.1 Genomic Responses 212

15.3.3.2 Proteomic Responses 212

15.3.3.3 Transcriptomic Responses 212

15.3.3.4 Metabolomic Responses 213

15.3.4 Ultraviolet (UV) Radiation Stress 213

15.3.4.1 Genomic Responses 213

15.3.4.2 Proteomic Responses 213

15.3.4.3 Transcriptomic Responses 213

15.3.4.4 Metabolomic Responses 213

15.3.5 Heavy Metal Stress Responses 214

15.3.5.1 Genomic Responses 214

15.3.5.2 Proteomic Responses 214

15.3.5.3 Transcriptomic Responses 214

15.3.5.4 Metabolomic Responses 214

15.3.6 Air Pollution Stress Responses 214

15.3.6.1 Genomic Responses 215

15.3.6.2 Proteomic Responses 215

15.3.6.3 Transcriptomic Responses 215

15.3.6.4 Metabolomic Responses 215

15.3.7 Climate Change Responses 215

15.3.7.1 Genomic Responses 215

15.3.7.2 Proteomic Responses 216

15.3.7.3 Transcriptomic Responses 216

15.3.7.4 Metabolomic Responses 216

15.4 Conclusion 216

References 216

16 Developing Stress-Tolerant Plants: Role of Small GTP Binding Proteins (RAB and RAN) 229
Manas K. Tripathy and Sudhir K. Sopory

16.1 Introduction 229

16.2 A Brief Overview of GTP-Binding Proteins 230

16.3 Small GTP-Binding Proteins 230

16.3.1 Rab 231

16.3.1.1 Role of RAB’s in Plant 231

16.3.2 Ran 234

16.3.2.1 Role of RAN in Plants 234

16.4 Conclusions 236

Acknowledgments 237

References 237

17 Biotechnological Strategies to Generate Climate-Smart Crops: Recent Advances and Way Forward 241
Jyoti Maurya, Roshan Kumar Singh, and Manoj Prasad

17.1 Introduction 241

17.2 Climate Change and Crop Yield 242

17.3 Effect of Climate Change on Crop Morpho-physiology, and Molecular Level 243

17.4 Plant Responses to Stress Conditions 244

17.5 Strategies to Combat Climate Change 245

17.5.1 Cultural and Conventional Methods 245

17.5.2 Multi-omics Approach 245

17.5.3 Biotechnological Approaches 248

17.5.3.1 Combating Climate Change Through Overexpression of Candidate Gene(s) 248

17.5.3.2 Small RNA-Mediated Gene Silencing Approach 249

17.5.3.3 Gene Editing Through Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Approach 250

17.6 Conclusion and Way Forward 251

Acknowledgments 252

Declaration of Interest Statement 252

References 252

18 Receptor-Like Kinases and ROS Signaling: Critical Arms of Plant Response to Stress 263
Samir Sharma

18.1 Preamble 263

18.2 Climate Change: The Agent of Stress 264

18.3 Abiotic Stress: A Severe Threat by Itself and a Window of Opportunity for Biotic Stress Agents 264

18.4 Plant Receptor-Like Kinases (RLKs) 265

18.5 Receptor-Like Cytosolic Kinases 267

18.6 Why Are Receptor-Like Cytosolic Kinases Needed? 268

18.7 Receptor-Like Cytosolic Kinases in Plant Defense 269

18.8 Receptor-Like Cytosolic Kinases in Plant Development 270

18.9 Reactive Oxygen Species: Dual Role in Plants and Links to Receptor-Like Protein Kinases 272

18.10 Conclusion 273

References 273

19 Phytohormones as a Novel Weapon in Management of Plant Stress Against Biotic Agents 277
Rewaj Subba, Swarnendu Roy, and Piyush Mathur

19.1 Introduction 277

19.2 Phytohormones and Biotic Stress Management 278

19.2.1 Salicylic Acid 278

19.2.2 Jasmonic Acid (JA) 278

19.2.3 Ethylene (ET) 279

19.2.4 Abscisic Acid (ABA) 279

19.3 Phytohormone Mediated Cross-Talk in Plant Defense Under Biotic Stress 281

References 282

20 Recent Perspectives of Drought Tolerance Traits: Physiology and Biochemistry 287
Priya Yadav, Mohammad Wahid Ansari, Narendra Tuteja, and Moaed Al Meselmani

20.1 Introduction 287

20.2 Effects and Response During Drought Stress on Physiological and Biochemical Traits of Plants 288

20.3 Recent Advances in Drought Stress Tolerance 289

20.4 Arbuscular Mycorrhizal Fungi (AMF) and Plant Growth-Promoting Rhizobacteria (PGPRs) in Drought Stress Tolerance 291

20.5 Genomic Level Approach in Drought Stress Tolerance 291

20.6 Conclusion 293

References 293

21 Understanding the Role of Key Transcription Factors in Regulating Salinity Tolerance in Plants 299
Sahana Basu and Gautam Kumar

21.1 Introduction 299

21.2 Transcription Factors Conferring Salinity Tolerance 299

21.2.1 APETALA2/Ethylene Responsive Factor 299

21.2.1.1 Structure of AP2/ERF Transcription Factors 301

21.2.1.2 Classification of AP2/ERF Transcription Factors 301

21.2.1.3 Role of AP2/ERF Transcription Factors in Salinity Tolerance 302

21.2.2 Wrky 302

21.2.2.1 Structure of WRKY Transcription Factors 302

21.2.2.2 Classification of WRKY Transcription Factors 302

21.2.2.3 Role of WRKY Transcription Factors in Salinity Tolerance 306

21.2.3 Basic Helix-Loop-Helix 307

21.2.3.1 Structure of bHLH Transcription Factors 307

21.2.3.2 Classification of bHLH Transcription Factors 307

21.2.3.3 Role of bHLH Transcription Factors in Salinity Tolerance 307

21.2.4 v-Myb Myeloblastosis Viral Oncogene Homolog 308

21.2.4.1 Structure of MYB Transcription Factors 308

21.2.4.2 Classification of MYB Transcription Factors 308

21.2.4.3 Role of MYB Transcription Factors in Salinity Tolerance 309

21.2.5 NAM (for no apical meristem), ATAF1 and −2, and CUC2 (for cup-shaped cotyledon) 309

21.2.5.1 Structure of NAC Transcription Factors 309

21.2.5.2 Classification of NAC Transcription Factors 309

21.2.5.3 Role of NAC Transcription Factors in Salinity Tolerance 310

21.2.6 Nuclear Factor-Y 310

21.2.6.1 Structure of NF-Y Transcription Factors 310

21.2.6.2 Classification of NF-Y Transcription Factors 310

21.2.6.3 Role of NF-Y Transcription Factors in Salinity Tolerance 311

21.2.7 Basic Leucine Zipper 311

21.2.7.1 Structure of bZIP Transcription Factors 311

21.2.7.2 Classification of bZIP Transcription Factors 312

21.2.7.3 Role of bZIP Transcription Factors in Salinity Tolerance 312

21.3 Conclusion 312

References 312

Part 5 Stress Management Strategies for Sustainable Agriculture 317

22 Seed Quality Assessment and Improvement Between Advancing Agriculture and Changing Environments 319
Andrea Pagano, Paola Pagano, Conrado Dueñas, Adriano Griffo, Shraddha Shridhar Gaonkar, Francesca Messina, Alma Balestrazzi, and Anca Macovei

22.1 Introduction: A Seed’s Viewpoint on Climate Change 319

22.2 Assessing Seed Quality: Invasive and Non-invasive Techniques for Grain Testing 321

22.3 Improving Seed Quality: Optimizing Priming Techniques to Face the Challenges of Climate Changes 324

22.4 Understanding Seed Quality: Molecular Hallmarks and Experimental Models for Future Perspectives in Seed Technology 327

22.5 Conclusive Remarks 329

References 329

23 CRISPR/Cas9 Genome Editing and Plant Stress Management 335
Isorchand Chongtham and Priya Yadav

23.1 Introduction 335

23.2 CRISPR/Cas 9 336

23.2.1 CRISPR Cas System 336

23.2.2 CRISPR Cas 9 337

23.2.3 CRISPR/Cas9 Mechanism 338

23.2.4 CRISPR/Cas9 Types of Gene Editing 339

23.3 Construct of the CRISPR/Cas 9 341

23.3.1 The gRNA 341

23.3.2 The Choice of Gene Regulatory Elements (GREs) 341

23.3.3 Multiplex CRISPR 341

23.4 Plant Genome Editing 343

23.4.1 Procedure 343

23.4.2 Plant Improvement Strategies Based on Genome Editing 344

23.5 Plant Stress 344

23.5.1 Plant Stress and Their Types 344

23.5.2 Plant Remedial Measures Toward Stress 345

23.6 Genome Editing for Plant Stress 346

23.6.1 Biotic Stress 348

23.6.1.1 Bacterium 348

23.6.1.2 Virus 348

23.6.1.3 Fungus 348

23.6.1.4 Insect 349

23.6.2 Abiotic Stress 349

23.6.2.1 Chemicals 349

23.6.2.2 Environmental 349

23.7 Elimination of CRISPR/Cas from the System After Genetic Editing 350

23.8 Prospects and Limitations 350

References 351

24 Ethylene Mediates Plant-Beneficial Fungi Interaction That Leads to Increased Nutrient Uptake, Improved Physiological Attributes, and Enhanced Plant Tolerance Under Salinity Stress 361
Priya Yadav, Mohammad Wahid Ansari, Narendra Tuteja, and Ratnum K. Wattal

24.1 Introduction 361

24.2 Plant Response Towards Salinity Stress 361

24.3 Plant–Fungal Interaction and the Mechanism of Plant Growth Promotion by Fungi 362

24.3.1 Nutrient Acquisition and Phytohormones Production 362

24.3.2 Activation of Systemic Resistance 364

24.3.3 Production of Siderophores 364

24.3.4 Production of Antibiotics and Secondary Metabolites 365

24.3.5 Protection to Biotic and Abiotic Stress 365

24.4 Fungi and Ethylene Production and Its Effects 365

24.5 Role and Mechanism of Ethylene in Salinity Stress Tolerance 366

24.6 Conclusion 367

References 367

25 Role of Chemical Additives in Plant Salinity Stress Mitigation 371
Priya Yadav, Mohammad Wahid Ansari, and Narendra Tuteja

25.1 Introduction 371

25.2 Types of Chemical Additives and Their Source 372

25.3 Application and Mechanism of Action 373

25.4 NO (Nitric Oxide) in Salt Stress Tolerance 374

25.5 Melatonin in Salt Stress Tolerance 374

25.6 Polyamines in Salt Stress Tolerance 374

25.7 Salicylic Acid (SA) in Salt Stress Tolerance 375

25.8 Ethylene in Salinity Stress Tolerance 376

25.9 Trehalose in Salinity Stress Tolerance 377

25.10 Kresoxim-Methyl (KM) in Salinity Stress Tolerance 377

25.11 Conclusion 377

References 377

26 Role of Secondary Metabolites in Stress Management Under Changing Climate Conditions 383
Priya Yadav and Zahid Hameed Siddiqui

26.1 Introduction 383

26.1.1 Types of Plant Secondary Metabolites 383

26.1.1.1 Phenolics 384

26.1.1.2 Terpenoids 384

26.1.1.3 Nitrogen-Containing Secondary Metabolites 384

26.2 Biosynthesis of Plant Secondary Metabolites 385

26.2.1 Role of Secondary Metabolites in Mitigating Abiotic Stress 388

26.2.2 Secondary Metabolites in Drought Stress Mitigation 389

26.2.2.1 Phenolic compounds and drought stress 389

26.2.2.2 Terpenoids in drought stress tolerance 389

26.2.3 Secondary Metabolites in Mitigating Salinity Stress 390

26.2.4 Secondary Metabolites as UV Scavengers 390

26.3 Heavy Metal Stress and Secondary Metabolites 390

26.3.1.1 Phenolic compounds and metal stress 391

26.3.2 Role of Secondary Metabolites in Biotic Stress Mitigation 392

26.3.2.1 Terpenoids and Biotic Stress 392

26.3.2.2 Phenolic Compounds and Biotic Stress 392

26.3.2.3 Nitrogen-Containing Compound and Biotic Stress 393

26.4 Counteradaptation of Insects Against Secondary Metabolites 393

26.5 Sustainable Crop Protection and Secondary Metabolites 393

26.6 Conclusion 393

References 394

27 Osmolytes: Efficient Oxidative Stress-Busters in Plants 399
Naser A. Anjum, Palaniswamy Thangavel, Faisal Rasheed, Asim Masood, Hadi Pirasteh-Anosheh, and Nafees A. Khan

27.1 Introduction 399

27.1.1 Plant Health, Stress Factors, and Oxidative Stress and Its Markers 399

27.1.2 Modulators of Oxidative Stress Markers and Antioxidant Metabolism 399

27.2 Osmolytes – An Overview 400

27.2.1 Role of Major Osmolytes in Protection of Plants Against Oxidative Stress 401

27.2.1.1 Betaines and Related Compounds 401

27.2.1.2 Proline 401

27.2.1.3 γ-Aminobutyric Acid (Gamma Amino Butyric Acid) 402

27.2.1.4 Polyols 402

27.2.1.5 Sugars 403

27.3 Conclusion and Perspectives 404

References 404

Index 411