Note: Intro -- Preface -- Contents -- Chapter 1: Plant Hormones and Plant Defense Response Against Pathogens -- 1.1 Perception and Signal Transduction: The Apoplastic Crosstalk -- 1.2 Cell Signaling: Perception of Danger Signal -- 1.2.1 Effectors and Receptors -- 1.2.2 Signal Transduction Pathways -- 1.3 Nitric Oxide, Hydrogen Peroxide and Melatonin as Mediators for Defense Responses -- 1.4 Phytohormones in Pathogen Resistance: Roles and Network -- 1.4.1 Salicylic Acid (SA) -- 1.4.2 Jasmonates (JA), Ethylene (ET) and Polyamines -- 1.4.3 Cytokinins (CK) -- 1.4.4 Auxin -- 1.4.5 Brassinosteroids (BRs) -- 1.4.6 Gibberellins (GAs) -- 1.5 Genome Editing Tools: CRISPR/Cas Technology as New Approach to Improve Crop Resistance -- 1.6 Conclusion -- References -- Chapter 2: Plant Hormones and Nutrient Deficiency Responses -- 2.1 Introduction -- 2.2 Experimental Techniques Used to Study the Role of Hormones in the Regulation of Nutrient Deficiency Responses -- 2.2.1 Hormone Measurements -- 2.2.2 Exogenous Application of Hormones, their Precursors and Inhibitors -- 2.2.3 Use of Mutants Altered in the Regulation of Responses -- 2.2.4 Use of Hormone Mutants -- 2.2.5 Split-Root Experiments -- 2.2.6 Use of Reciprocally Grafted Plants Between WT and Mutants or Transgenic Lines Altered in the Regulation of Responses -- 2.2.7 Use of Detopped Plants, Girdled Plants or Foliar Application of Nutrients and Other Compounds -- 2.2.8 Molecular Techniques (Transcriptomic, Proteomic, Metabolomic, Y2H, BiFC, …) -- 2.3 Nutrient Deficiency Responses -- 2.3.1 General Adaptive Responses -- 2.3.1.1 Shoot-Root Growth Alterations/TOR/SnRKs -- 2.3.1.2 Recycling/Authophagy -- 2.3.1.3 Substitution -- 2.3.2 Specific Responses -- 2.3.2.1 Physiological Responses -- 2.3.2.2 Morphological Responses -- 2.4 Sensors and Transceptors. , 2.5 Role of Hormones in the Regulation of Nutrient Deficiency Responses -- 2.5.1 Role of Hormones on General Adaptive Responses -- 2.5.1.1 Role of Hormones on Shoot-Root Growth Alterations/TOR/SnRKs -- 2.5.1.2 Role of Hormones on Recycling/Authophagy -- 2.5.2 Role of Hormones on Specific Responses -- 2.5.2.1 Role of Hormones on Physiological Responses -- 2.5.2.2 Role of Hormones on Morphological Responses -- 2.6 Crosstalk Between Different Hormones, and Between Hormones and Other Signaling Substances -- 2.7 Concluding Remarks and Future Perspectives -- References -- Chapter 3: Seed Germination: Explicit Crosstalk Between Hormones and ROS -- 3.1 Introduction -- 3.2 Seed Germination: First Sign of Perceptible Growth and Hormonal Interplay -- 3.3 ROS, an Inevitable Player - Signaling and/or Direct Action in Growth -- 3.4 Cross-Talk Between Hormone and ROS During Seed Germination -- 3.5 ROS - PM H+-ATPase - Hormones: Extension of the Signaling Network -- 3.6 Reactive Nitrogen Species (RNS): Another Potential Candidate to Play for Signaling -- 3.7 Conclusion -- References -- Chapter 4: Hormones and Light-Regulated Seedling Development -- 4.1 Light-Regulated Responses During Seedling Development -- 4.2 Light Perception and Signaling in Plants -- 4.2.1 Perception of Light Signals -- 4.2.1.1 Perception of Red and Far-Red Lights -- 4.2.1.2 Perception of Blue Light -- 4.2.1.3 Perception of UV-B Light -- 4.2.2 Transcriptional Hubs Regulating Light-Mediated Changes in Gene Expression -- 4.3 Hormonal Regulation of Dark-Adapted Seedling Growth Beneath the Soil -- 4.4 Hormones Mediate Light-Induced Opening and Expansion of Cotyledons -- 4.5 Regulation of Chlorophyll and Anthocyanin Accumulation by Hormones -- 4.6 Hormones Control Hypocotyl Growth Under Light -- 4.7 Hormonal Regulation of Phototropism and Shade Avoidance Response -- 4.8 Conclusion -- References. , Chapter 5: Light-Mediated Regulation of Plant Hormone Metabolism -- 5.1 Initial Considerations -- 5.2 A Brief Update on Light Signaling in Higher Plants -- 5.3 Mechanistic Links Between Light Perception and Hormone Metabolism in Higher Plants: A Wide Spectrum of Possibilities -- 5.3.1 Light and Auxin Metabolism -- 5.3.2 Light and Gibberellin Metabolism -- 5.3.3 Light and Abscisic Acid Metabolism -- 5.3.4 Light and Cytokinin Metabolism -- 5.3.5 Light and Ethylene Metabolism -- 5.3.6 Light and Brassinosteroid Metabolism -- 5.4 Concluding Remarks -- References -- Chapter 6: Hormones in Photoperiodic Flower Induction -- 6.1 Introduction -- 6.2 Photoperiodic Induction of Flowering -- 6.3 The Effect of Hormones on the Induction of Flowering of Plants with Different Photoperiodic Requirements -- 6.4 Effect of Photoperiod on Hormone Metabolism and Signal Transduction Pathways During Generative Induction -- 6.5 Mechanisms of Hormone Action During Photoperiodic Induction of Flowering -- 6.6 Interactions of Hormones in the Regulation of Flowering Induction in Ipomoea nil -- 6.7 Summary -- References -- Chapter 7: Recent Insights into Auxin-Mediated Molecular Cross Talk Events Associated with Regulation of Root Growth and Architecture During Abiotic Stress in Plants -- 7.1 Introduction -- 7.2 Regulation of Root Architecture -- 7.3 Auxin Efflux Carriers Coordinate Auxin Distribution in Roots During Abiotic Stress -- 7.4 Abiotic-Stress Induced Regulation of Auxin Homoeostasis in Roots -- 7.5 NO and JA Precisely Regulate Root Development by Acting Through Auxin-Mediated Signaling Pathway -- 7.6 ABA and Ethylene Crosstalk Integrates Auxin Signalling in Plant Roots During Osmotic Stress -- 7.7 Hydrogen Sulphide and Indoleamine-Mediated Auxin Signalling in Roots -- 7.8 Concluding Remarks and Future Perspectives -- References. , Chapter 8: Abscisic Acid and Fruit Ripening: Its Role in Grapevine Acclimation to the Environment, a Case of Study -- 8.1 ABA Biochemistry -- 8.2 ABA Physiology -- 8.3 Relevance of ABA in the Physiology of Fruit Ripening -- 8.4 ABA and Grapevine -- 8.5 Conclusions Regarding Grapevines and ABA -- References -- Chapter 9: Biosynthesis and Molecular Mechanism of Brassinosteroids Action -- 9.1 Introduction -- 9.2 Chemical Structure of Brassinosteroids -- 9.3 Metabolism of Brassinosteroids -- 9.4 Brassinosteroids Biosynthesis Pathways -- 9.4.1 Early Steps of Brassinosteroids Biosynthesis -- 9.4.2 Biosynthesis of C27-Brassinosteroids -- 9.4.3 Biosynthesis of C28-Brassinosteroids -- 9.4.4 Biosynthesis of C29-Brassinosteroids -- 9.4.5 Inhibitors of Brassinosteroid Biosynthesis -- 9.5 Signal Transduction of Brassinosteroids -- 9.5.1 Structure of BRI1/BAK1 Receptors -- 9.5.2 Brassinosteroids' Crosstalk with Other Phytohormones -- 9.6 Conclusions and Future Perspectives -- References -- Chapter 10: Regulatory Role of Melatonin in the Redox Network of Plants and Plant Hormone Relationship in Stress -- 10.1 Introduction -- 10.2 Metabolism of ROS and RNS -- 10.3 Melatonin and ROS/RNS -- 10.4 Melatonin in the ROS/RNS Network in Plants -- 10.5 Melatonin and Gene Regulation in the Redox Network -- 10.6 Melatonin and Plant Hormone Relationship -- 10.6.1 Auxin -- 10.6.2 Gibberellin, Abscisic Acid and Cytokinins -- 10.6.3 Ethylene -- 10.6.4 Salicylic Acid and Jasmonic Acid -- 10.6.5 Brassinosteroids, Polyamines and Strigolactones -- 10.7 Conclusions -- References -- Chapter 11: Tryptophan: A Precursor of Signaling Molecules in Higher Plants -- 11.1 Introduction -- 11.2 Tryptophan Is Generated in the Shikimate (Chorismate) Pathway -- 11.2.1 Auxin, Indole-3-Acetic Acid (IAA) -- 11.2.2 Serotonin (5-Hydroxytryptamine, 5-HT) -- 11.2.3 Melatonin (N-Acetyl-5-Methoxytryptamine). , 11.2.3.1 Abiotic Stress -- 11.2.3.2 Fruit Ripening and Postharvest -- 11.3 Conclusions and Future Perspectives -- References -- Chapter 12: GABA and Proline Metabolism in Response to Stress -- 12.1 Introduction -- 12.2 Biosynthesis and Degradation of GABA in Plants -- 12.3 Proline Metabolism in Plants -- 12.4 GABA and Proline Involvement in Abiotic Stresses Responses -- 12.5 GABA and Proline Responses in Plants Under Biotic Stresses -- 12.6 Potential Functions of GABA in Plant Response to Abiotic and Biotic Stress -- 12.7 Potential Functional Implications of Proline in Plants Under Stress -- 12.8 Potential Links Between GABA and Proline Metabolism and Hormone Signalling -- 12.9 Upcoming Challenges for the Understanding of Proline and GABA Contributions to Stress Tolerance in Plants -- References.