Iron Chelation in Plants and Soil Microorganisms provides an introduction to the basic biological processes of plants that require iron and those affected by iron deficiency. The book aims to stimulate research in the area of iron metabolism in plants and plant-associated microorganisms. The book is organized into three parts. Part I provides an overview of research methods used in the study of iron chelation relevant to plant biology. Key topics covered include microbial siderophores, phytosiderophores, and plant and microbial ferritins. Part II discusses the molecular approach to iron chelation, which includes molecular biology, enzymology, and iron uptake activities. Part III addresses various physiological and chemical characteristics of the iron stress response. This book was written for scientists involved in plant physiology, agronomy, phytopathology, plant control, and soil microbiology. It may also be of interest to those studying soil chemistry, plant-mineral relationships, horticulture, in vivo and in vitro iron measurements, and microbial ecology. In addition, the book can serve as reference for specialty courses and laboratories conducting research on iron nutrition in plants as well as individuals engaged in iron-related research.

Table of Contents:
Contributors Preface Part I Production and Characteristics of Metal Chelators 1 Classes of Microbial Siderophores I. Introduction II. Classes of Microbial Siderophores III. Ecological Significance of Bacterial and Fungal Siderophores References 2 Biochemical and Genetic Analysis of Siderophores Produced by Plant-Associated Pseudomonas and Erwinia Species I. Introduction II. Methods for Biochemical and Biological Analysis for Siderophores of Pseudomonas and Erwinia Species III. Genetic Analysis of Siderophores Produced by Erwinia and Pseudomonas Species IV. Conclusions References 3 Growth Conditions for the Demonstration of Siderophores and Iron-Repressible Outer Membrane Proteins in Soil Bacteria, with an Emphasis on Free-Living Diazotrophs I. Iron and Aerobic Growth II. Bacterial Siderophores: A Brief Overview III. High Affinity and Low Affinity Iron Uptake Systems IV. Iron-Sufficient Growth V. Iron-Limited Growth: Deferration of the Growth Medium VI. Iron-Limited Growth: Withholding Iron from the Cells VII. Mineral Iron Sources to Limit Iron Availability VIII. Use of Mineral Iron by Diazotrophic Bacteria IX. Chelation of Other Ions by Siderophores X. Demonstration of Iron-Repressible Outer Membrane Proteins XI. Other Bacterial Activities Influenced by Iron Limitation References 4 Production of Phytosiderophores I. Introduction II. Categorization and Distribution of Phytosiderophores III. Assay Methods IV. Method for Isolation from Barley Root Exudates V. Overview of Iron Acquisition System in Barley Roots VI. Conclusion References 5 Plant and Microbial Ferritins I. General Properties of the Ferritin Family II. Ferritin Protein Coat III. Ferritin Iron Core IV. Ferritin Regulation and Gene Expression V. Summary and Conclusions References 6 Glutathione-Derived Metal-Binding Polypeptides and Metallothioneins I. Introduction II. Glutathione-Derived Metal-Binding Polypeptides III. Metallothioneins IV. Conclusions References Part II Enzymes and Interaction Systems 7 Overview of Bacterial Iron Transport and Siderophore Systems in Rhizobia I. Introduction II. Diverse Bacterial Iron Uptake Systems III. Iron Transport Systems in Escherichia coli IV. Iron Transport in Rhizobia V. Discussion References 8 Iron and the Nodule I. Introductory Comments on the Role of Iron in the Symbioses II. Iron in the Developing and Mature Nodule III. Sources IV. Summary References 9 Kinetics, Energetics, and Mechanisms of Siderophore Iron Transport in Fungi I. Introduction II. Structural Aspects and Classes of Fungal Siderophores III. Specificity of Siderophore Iron Transport IV. Measurement of Transport V. Siderophore Iron Transport in Selected Fungi VI. Siderophores as Iron Storage Molecules VII. Iron Uptake in the Absence of Siderophore Production References 10 Enzymatic Reduction of Iron in Siderophores I. Introduction II. Ferrisiderophore Reductase Assay III. Use of the Ferrisiderophore Reductase Assay to Analyze Column Chromatography Fractions IV. Localization of Enzyme Activity in Polyacrylamide Gels V. Use of DCIP as a Substrate to Monitor Enzyme Activity VI. Study of Enzyme Kinetics with Ferrisiderophore Reductase VII. Ferrisiderophore Reductase in Plants VIII. Summary References 11 Role of Iron in Fungal Phytopathologies I. Introduction II. Effect of Iron on Soilborne Fungal Diseases III. Effect of Iron on Aerial Fungal Diseases IV. Involvement of Iron in Phytotoxins V. Concluding Remarks References 12 Role of Iron in the Suppression of Bacterial Plant Pathogens by Fluorescent Pseudomonads I. Introduction II. Plant Growth Promotion by Suppression of Deleterious Rhizobacteria III. Specificity of Pseudobactin Siderophores and Their Receptors IV. Conclusions and Prospects References 13 Ferrochelatase and Related Enzymes I. Introduction II. Biosynthesis of Heme and Chlorophyll III. Ferrochelatase IV. Enzymes Influenced by Iron V. Perspectives References 14 Three Genetically Distinct Nitrogenase Systems in Azotobacter vinelandii I. Introduction II. Biochemical Properties of Alternative Molybdenum-Independent Nitrogenases III. Genetics of Alternative Nitrogen Fixation Systems IV. Occurrence of Alternative Nitrogenases in Diazotrophs Other than the Azotobacteriaceae V. Future Prospects References Part III Physiological and Chemical Characteristics of the Iron Stress Response 15 Iron and Plant Pigments I. Iron and the Photosynthetic Pigments of Higher Plants II. Measuring Plant Pigments in Iron Deficiency Studies III. Sampling and Expression of Results in Iron Deficiency Studies IV. Final Considerations References 16 Plant Iron Uptake Physiology by Nonsiderophore Systems I. Introduction II. Iron Forms III. Plant Iron Stress Responses References 17 Selected Physiological Responses Associated with Fe(III) and Fe(II) Metabolism I. Introduction II. Role of Iron in Rhizobia-Legume Symbiosis III. Studies with Fe(II) IV. Visualization of Iron Metabolism V. Perspectives References 18 A Case Study with Soybeans: Iron Efficiency Evaluation in Field Tests Compared with Controlled Conditions I. Introduction II. Screening Techniques for Evaluation of Fe Efficiency III. Future Approaches to Fe Efficiency Evaluation References 19 Assays for Microbial Siderophores I. Introduction II. Siderophore Assays Based on Chemical Methods III. Siderophore Assays Based on Biological Methods References 20 Mössbauer Spectroscopy I. Theory II. Ferritin III. Fungi and Bacteria IV. Plants References 21 Sample Preparation and Determination of Iron in Biological Materials I. Decontamination of Samples II. Oven Drying III. Particle-Size Reduction IV. Organic Matter Destruction V. Methods of Iron Analysis VI. Colorimetric Determination of Iron VII. Interpretation of Iron Analysis Data for Biological Samples VIII. Frequency Distribution of Iron in Plants IX. Active Iron X. Iron Concentrations in Biological Research Materials XI. Visual Symptoms for Detection of Iron Deficiency XII. Enzyme Assays to Determine Iron Status of Plants References 22 Evaluation of Soil Iron I. Introduction II. Principal Forms of Soil Iron III. Mechanisms of Dissolution of Soil Iron IV. Determination of Total Soil Iron V. Determination of Total Free Iron Oxide VI. Determination of "Active" Iron Oxides VII. Determination of Organically Bound VIII. Water-Soluble and Exchangeable Soil Iron IX. Indices for Availability of Iron to Plants and Microbes X. Analysis of Iron in Soil Digests and Extracts XI. Conclusions References Index