Note: Intro -- Preface -- Contents -- About the Editors -- 1: Agriculturally Important Microbes: Challenges and Opportunities -- 1.1 Introduction -- 1.2 Azotobacter -- 1.2.1 Action Mechanism of Plant Growth-Promoting Rhizobacteria -- 1.2.2 Azotobacter as Biofertilizers and Biocontrol Agents -- 1.3 Serratia spp. -- 1.3.1 Action Mechanism as Plant Growth-Promoting Rhizobacteria -- 1.3.2 Serratia as Biocontrol Agents -- 1.3.3 Serratia in Abiotic Stress Tolerance -- 1.4 Bacillus spp -- 1.5 Pseudomonas -- 1.6 Challenges to the Use of Agriculturally Important Microbes -- 1.6.1 Screening of Microbes and Poor Shelf Life of Bioformulation -- 1.6.2 Lack of Field Reproducibly of PGPR Performance -- 1.6.3 Skewed Perception -- 1.6.4 Challenges in Product Commercialization -- 1.6.5 Challenges in Products Registration and Patent Filing -- 1.7 Future Aspects -- References -- 2: Agriculturally Important Microorganism: Understanding the Functionality and Mechanisms for Sustainable Farming -- 2.1 The Concept of Plant Microbiome and the Rhizobiome -- 2.2 Agriculturally Important Microorganisms (AIMs) -- 2.3 Diversity and Functionality of AIMs -- 2.3.1 Diversity and Interrelationship -- 2.3.2 Diversity and Functionality -- 2.3.2.1 Biocontrol Agents (BCA) -- 2.3.2.2 Plant Growth-Promoting Rhizobacteria (PGPR) -- 2.3.2.3 Plant Growth-Promoting Fungi (PGPF) -- 2.3.2.4 Arbuscular Mycorrhizal Fungi (AMF) -- 2.3.2.5 Endophytes -- 2.3.2.6 Actinomycetes -- 2.4 Mechanisms Involved in Plant and Soil Health Improvement -- 2.4.1 Direct Mechanism -- 2.4.1.1 Biological Fixation of the Atmospheric Nitrogen -- 2.4.1.2 Solubilization of Phosphates by Microorganisms -- 2.4.1.3 Production of Siderophores by Microorganisms -- 2.4.1.4 Production of Phytohormones -- 2.4.2 Indirect Mechanism -- 2.4.2.1 Induction of Resistance in Host Plants by AIMs. , 2.5 Molecular Signaling in the Rhizosphere and Beyond: The Cross Talk -- 2.5.1 Microbe Triggered Immunity -- 2.5.2 Microbial Signaling -- 2.6 Current and Future Challenges -- 2.7 Conclusion -- References -- 3: Microbial Diversity of Different Agroecosystems: Current Research and Future Challenges -- 3.1 Introduction -- 3.2 Microbial Diversity of Agroecosystems -- 3.2.1 Temporal and Spatial Distribution -- 3.2.2 Diversity in Different Agroecosystems -- 3.2.2.1 Jhum Agroecosystem -- 3.2.2.2 Microbial Diversity in Sundarbans -- 3.2.2.3 Agroecosystem of North Western Himalayas -- 3.2.2.4 Thar Agroecosystem -- 3.2.2.5 Coffee Shade Tree Agroecosystem -- 3.2.2.6 Apatani Wet Rice Agroecosystem -- 3.2.2.7 Agroecosystem of Leh Ladakh -- 3.2.2.8 Effect of Changing Environment on Microbial Diversity -- 3.3 Role of Microorganisms in Ecosystem Functioning -- 3.3.1 Nutrient Cycling -- 3.3.2 Soil Formation and Weathering -- 3.3.3 Waste Recycling -- 3.4 Effect of Changing Environment on Microbial Diversity -- 3.4.1 Soil Biodiversity, Resistance, and Resilience -- 3.4.2 Nitrogen Deposition -- 3.4.3 Elevated Carbon Concentration -- 3.5 Mitigation Strategies -- 3.5.1 Soil Biodiversity and Sustainable Agricultural Practices -- 3.5.2 Soil Biodiversity and Restoration Ecology -- 3.5.3 Agroecosystem Management with Core Microbiomes -- 3.6 Conclusion -- References -- 4: Soil Microbial Biomass asan Index of Soil Quality and Fertility in Different Land Use Systems of Northeast India -- 4.1 Introduction -- 4.2 Role of Soil Microbes in an Ecosystem -- 4.3 Soil Microbial Biomass -- 4.4 Land-Use Types of Northeast India -- 4.5 Soil Nutrient Status of Different Land-Use Types of Northeast India -- 4.6 Changes in Microbial Biomass C, N, and P Due to Land-Use Types -- 4.7 Microbial C:N:P Stoichiometry in Different Land-Use Types of Northeast India -- 4.7.1 Microbial C:N Ratio. , 4.7.2 Microbial C:P Ratio -- 4.7.3 Microbial N:P Ratio -- 4.8 Soil Nutrient Fractions in Microbial Biomass of Different Land Uses of Northeast India -- 4.9 Conclusion -- References -- 5: Microbes and Plant Mineral Nutrition -- 5.1 Introduction -- 5.2 An Overview of Soil Microorganisms for the Availability of Nutrients in Plants -- 5.3 Soil Microbes Induced Nitrogen Uptake by Plants -- 5.4 Soil Microbes Induced Phosphate Uptake by Plants -- 5.5 Soil Microbes Induced Potassium Uptake by Plants -- 5.6 Soil Microbes Mediated Micronutrient Acquisition in Plants -- 5.6.1 Iron -- 5.6.2 Zinc -- 5.7 Copper -- 5.7.1 Manganese -- 5.8 Future Perspectives and Challenges in Plant Microbe Based Agro-Inputs -- 5.9 Conclusion -- References -- 6: Drought Stress Alleviation in Plants by Soil Microbial Interactions -- 6.1 Introduction -- 6.2 Stresses, Soil Structure and Their Effect on Microbial Colonization -- 6.3 Microbes: As Protective Companion to Plants -- 6.3.1 Bacteria -- 6.3.2 AM Fungi -- 6.3.3 Actinomycetes -- 6.3.4 Virus -- 6.4 Drought Stress Management -- 6.4.1 Growth, Biomass, and Photosynthesis -- 6.4.2 Mineral Uptake and Mobilization -- 6.4.3 Redox Homeostasis and Membrane Stabilization -- 6.4.4 Osmolytes Regulation -- 6.4.5 Hormonal Regulation and Volatiles -- 6.5 Conclusion and Future Prospective -- References -- 7: Role of Nitrogen-Fixing Microorganisms for Plant and Soil Health -- 7.1 Introduction -- 7.2 Biological Nitrogen Fixation -- 7.2.1 Symbiotic Nitrogen Fixation -- 7.2.2 Invasion and Infection -- 7.2.2.1 Release of Flavonoids -- 7.2.2.2 Nod Factor -- 7.2.2.3 Nod Factor Perception -- 7.2.2.4 Responses to Nod Factor -- 7.2.2.5 Root Hair Curling -- 7.2.2.6 Nodule Organogenesis -- 7.2.3 Regulation of Nitrogen Fixation -- 7.2.4 Free Living and Associative Nitrogen Fixation -- 7.2.4.1 Free-Living Diazotrophs -- 7.2.4.1.1 Azotobacter vinelandii. , 7.2.4.1.2 Cyanobacteria -- 7.2.4.2 Associative Diazotrophs -- 7.3 Application in Management Practices -- 7.4 Conclusions -- References -- 8: Serendipita indica Mediated Drought and Heavy Metal Stress Tolerance in Plants -- 8.1 Introduction -- 8.2 Role of S. indica in Heavy Metal Stress Tolerance -- 8.3 Drought Stress Tolerance Mediated by S. indica -- 8.4 Conclusion -- References -- 9: Role of Rhizosphere and Endophytic Microbes in Alleviation of Biotic and Abiotic Stress in Plants -- 9.1 Introduction -- 9.2 Biotic and Abiotic Stress and Their Impacts on Crop Production -- 9.3 Diversity and Consortium of Rhizosphere and Endophytic Microbes -- 9.4 Environmental and Host Influence on the Rhizosphere and Endophytic Microbes -- 9.4.1 Environmental Effects -- 9.4.2 Effects of Agronomic Practices -- 9.4.3 Influence of Host Plants -- 9.5 Role of Rhizosphere and Endophytic Microbes in Agriculture -- 9.5.1 Plant Growth Promotion by Increasing Nutrient Availability -- 9.5.2 Plant Growth Promotion by Hormone Production -- 9.5.3 Defend Plants Against Biotic Stress -- 9.5.4 Increase Abiotic Stress Tolerance in Plants -- 9.6 Molecular Mechanisms of Stress Alleviation -- 9.6.1 Microbe-Mediated Induced Systemic Tolerance to Abiotic Stress -- 9.6.1.1 Amelioration of Nutrient Deficiency -- 9.6.1.2 Water, Temperature and Salinity Stress Tolerance -- 9.6.1.3 Tolerance of Stress Due to Heavy Metal and Herbicide Toxicity -- 9.6.2 Microbe-Mediated Induced Systemic Resistance to Biotic Stresses -- 9.6.3 Defence Mechanisms of Rhizosphere and Endophytic Microbes Against Biotic Stresses -- 9.6.4 Defence Against Phytopathogens -- 9.6.5 Defence Against Phytophagous Insects -- 9.7 Influence of Rhizosphere and Endophytic Microbes on Product Quality -- 9.8 Biotechnological Approaches for Enhancing the Effectiveness of Rhizosphere and Endophytic Microbes. , 9.9 Conclusion and Future Perspective -- References -- 10: Augmentation of Plant Salt Stress Tolerance by Microorganisms -- 10.1 Introduction -- 10.1.1 Impact of Soil Salinization on Plants -- 10.1.2 Plant Growth-Promoting Bacteria -- 10.1.3 Mycorrhizal and Endophytic Fungi -- 10.2 Molecular Mechanism Involved in Salt Tolerance -- 10.2.1 General Mechanisms of Augmenting Salt Tolerance in Plants -- 10.2.2 Specific Mechanisms in Regulating Salt Tolerance by Microorganisms -- 10.3 Microbial Stimulation of Salt Tolerance -- 10.3.1 Salt Tolerance by Bacteria -- 10.3.2 Salt Tolerance by Fungi -- 10.4 Combinatorial Benefits of PGPB and Mycorrhizal Fungi -- 10.5 Conclusion and Future Perspective -- References -- 11: Impact of Plant Exudates on Soil Microbiomes -- 11.1 Rhizosphere -- 11.2 Root Exudate -- 11.2.1 Rhizodeposition -- 11.2.2 Root Exudate and Organic Acid -- 11.3 Plant Interaction with Microbes -- 11.4 Root Exudate Impact -- References -- 12: Global Climate Change and Microbial Ecology: Current Scenario and Management -- 12.1 Introduction -- 12.2 Microbial Functions in the Environment -- 12.3 Applications in Agriculture -- 12.3.1 Nutrient Recycling -- 12.3.2 Sustaining Optimal Soil Structure for Agriculture -- 12.3.3 Mineralization and Humification -- 12.4 Role of Soil Enzymes in Decomposition of Organic Matter -- 12.4.1 Amylase -- 12.4.2 Arylsulfatase -- 12.4.3 β-Glucosidase -- 12.4.4 Cellulose -- 12.4.5 Chitinase -- 12.4.6 Dehydrogenase -- 12.4.7 Phosphatase -- 12.4.8 Proteases -- 12.5 Pollutants Mitigation -- 12.6 Bioremediation -- 12.7 Impact of Climate Change on the World´s Agriculture -- 12.7.1 Effects of Temperature -- 12.7.2 Moisture Fluctuations -- 12.7.3 Significance of Terrestrial and Aquatic Ecosystems -- 12.8 The Relevance of the Microbial World to the Problem -- 12.9 Role of Terrestrial Microbes. , 12.9.1 Production of Carbon Dioxide and Methane.