Global Climate Change and Plant Stress Management

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