Physiology and Biochemistry of Plant-Pathogen Interactions

1 Definition.- I. Introduction.- II. Definition of a Few Terms.- A. Plant Disease.- B. Symptoms.- C. Pathogenicity and Virulence.- D. Pathogenesis.- E. Tolerance.- F. Compatibility and Incompatibility.- G. Hypersensitive Reaction.- H. Biotrophs.- 2 Attraction to and Penetration of Plants by Pathogens.- I. Introduction.- II. Attraction of Pathogens to Plants.- A. Chemotaxis.- B. Electrotaxis.- C. Motility.- III. Penetration.- A. Passive Penetration.- B. Active Penetration.- IV. Factors Influencing Attraction, Penetration, and Infection Processes.- A. Temperature.- B. Moisture.- C. Gas Composition.- 3 The Role of Pathogen-Produced Cell-Wall-Degrading Enzymes in Pathogenesis.- I. Introduction.- II. Structure and Chemistry of the Cell Wall.- A. Structure of the Cell Wall.- B. Chemistry of Cell Wall Components.- III. Pathogen-Produced Cell-Wall-Degrading Enzymes.- A. Pectolytic Enzymes.- B. Cellulose-Degrading Enzymes.- C. Hemicellulose-Degrading Enzymes.- D. Pattern of Production of Cell-Wall-Degrading Enzymes.- E. Factors Influencing the Activity of Pathogen-Produced Cell-Wall-Degrading Enzymes.- F. Evidence for the Involvement of Pathogen-Produced Enzymes in Pathogenesis.- G. The Role of Cell-Wall-Degrading Enzymes in Tissue Maceration and Cell Death.- 4 The Role of Pathogen-Produced Toxins in Pathogenesis.- I. Introduction.- II. Definition and Classification of Pathogen-Produced Toxins.- III. Toxin Categories.- A. Vivotoxin.- B. Pathotoxin.- C. Host-Selective (-Specific) Toxin.- IV. Evaluation of the Criteria Used to Establish the Role of Toxins in Pathogenesis.- A. Isolation of the Toxin from Diseased Plants.- B. Reproduction of Disease Symptoms by the Toxin.- C. Correlation between Pathogenicity and the Level of Toxin Produced in Vitro.- D. Correlation between Disease Susceptibility and Sensitivity to Toxins.- E. Genetic Analysis of the Host, the Pathogen, or Both.- V. Host-Selective Toxins.- A. Victorin.- B. T Toxin.- C. HC Toxin.- D. HS Toxin.- E. PC Toxin.- F. PM Toxin.- G. AK Toxin.- H. AM Toxin.- I. AA Toxin.- VI. Nonselective Toxins.- A. Amylovorin.- B. Tentoxin.- C. Phaseolotoxin.- D. Tabtoxin and Tabtoxinine-?-lactam.- E. Syringomycin and Syringotoxin.- F. Coronatine.- G. Fusicoccin.- H. Fumaric Acid.- I. Oxalic Acid.- J. Fusaric Acid.- K. Ethyl and Methyl Acetate.- L. Ammonia.- VII. Mode of Action of Toxins.- A. Effect on Mitochondria.- B. Effect on Membrane Permeability.- C. Effect on Photosynthesis.- D. Effect on Enzymes.- E. Growth Regulator Effect.- VIII. Toxin Binding Sites.- IX. Mechanism of Plant Resistance to Toxin-Producing Pathogens.- 5 Alterations in Permeability Caused by Disease.- I. Introduction.- II. Composition and Structure of Membranes.- III. Cell Permeability Theories.- A. Membrane Theory.- B. Sorption Theory.- C. Cytotic Theory.- IV. Changes in Cell Permeability Caused by Disease.- V. Mechanisms of Permeability Changes in Diseased Plants.- A. Activation of the Plasmalemma ATPase.- B. Effects of Pathogen-Produced Toxins on Specific Components of the Transport System.- C. Disruption of Energy Supply for the Maintenance and Repair of Membranes.- D. Degradation of Lipid and Protein Components of Membranes by Pathogen-Produced Enzymes.- 6 Alterations in Water Relations Caused by Disease.- I. Introduction.- II. Definition of a Few Terms.- A. Water Potential.- B. Osmotic, Pressure, and Matric Potentials.- C. Relative Water Content.- III. Water Movement in Plants.- A. Water Movement in Healthy Plants.- B. Water Movement in Diseased Plants.- IV. Transpiration.- A. Transpiration in Healthy Plants.- B. Transpiration in Diseased Plants.- V. Disruption of Membrane Permeability in Leaf Cells by Pathogen-Produced Substances.- VI. Water Potential and Disease Severity.- VII. Assessment of the Nature of Water Relations Changes in Diseased Plants.- 7 Disease-Induced Alterations in Carbohydrate Metabolism.- I. Introduction.- II. Disease-Induced Alterations in Photosynthesis.- A. Changes in Photosynthesis in Plants Infected with Viruses and Biotrophic Fungi.- B. Changes in Photosynthesis in Plants Infected with Nonbiotrophs.- III. Mechanism of Disease-Induced Alterations in Photosynthesis.- A. Decline in the Capture of Light Energy.- B. Changes in the Rate of CO2 Uptake.- C. Effect of Pathogen-Produced Toxins.- IV. Disease-Induced Alterations in Transport of Photoassimilates.- V. Mechanism of Disease-Induced Alterations in Photoassimilate Transport.- VI. Disease-Induced Increases in Respiration.- VII. Mechanism of Disease-Induced Increases in Respiration.- A. Uncoupling of Phosphorylation from Electron Transport.- B. Increased Activity of Pentose Phosphate Pathway.- C. Increased Activity of Noncytochrome Oxidases.- VIII. Regulation of Carbohydrate Metabolism.- IX. Significance of Disease-Induced Alterations in Respiration.- X. Future Studies.- 8 Pathological Alterations in Transcription and Translation.- I. Introduction.- II. Disease-Induced Alterations in Transcription.- A. Changes in Chromatin.- B. Changes in the Activity of RNA Polymerases.- C. Changes in the Activity of Ribonucleases.- D. Changes in the Level of RNA.- E. Changes in Plant Nuclei.- III. Disease-Induced Alterations in Translation.- A. Changes in Enzymes.- B. Changes in Proteins.- IV. Conclusions.- 9 Alterations in Phenol Metabolism Caused by Disease.- I. Introduction.- II. Biosynthetic Pathways of Phenolic Compounds.- III. Disease-Induced Alterations in Phenol Metabolism.- A. Changes in the Level of Phenolic Compounds.- B. Changes in the Activities of Enzymes Involved in Phenol Metabolism.- 10 Growth Regulator Imbalance in Plant Disease.- I. Introduction.- II. Known Growth Regulators.- A. Indoleacetic Acid.- B. Ethylene.- C. Cytokinins.- D. Gibberellins.- E. Abscisic Acid.- III. Pathogen-Produced Toxins with Growth Regulator Activity.- IV. Involvement of Growth Regulators in Certain Disease-Induced Abnormalities.- A. Gall and Overgrowth.- B. Fasciation of Peas.- C. Excessive Elongation.- D. Stunting.- E. Water Stress and Wilting.- F. Leaf Abscission.- G. Green-Island Formation.- H. Altered Translocation.- V. Mechanisms of Change in Indoleacetic Acid Content of Diseased Tissue.- A. Changes in the Level of Indoleacetic Acid Precursors.- B. Indoleacetic Acid Oxidation.- C. Conjugation of Indoleacetic Acid with Inactivator and Protector Molecules.- D. Interference with Indoleacetic Acid Transport.- VI. Influence of Growth Regulators on the Outcome of Disease Reaction.- A. Indoleacetic Acid.- B. Cytokinins.- C. Ethylene.- VII. Limitations of Growth Regulator Studies.- VIII. Discussion.- 11 Crown Gall Tumor Formation.- I. Introduction.- II. The Bacterium.- III. Physiology of Crown Gall Tumor.- A. Phytohormone Independence.- B. Synthesis of Opines.- IV. Tumor Development.- A. Attachment of the Bacterium to Plant Cell—Wound Requirement.- B. The Nature of the Tumor-Inducing Principle.- V. Relations among Bacterial Plasmids.- VI. Mechanism of Transformation.- A. Acquisition of Bacterial Plasmid DNA.- B. Incorporation of T-DNA into Plant DNA.- C. Transcription of Incorporated T-DNA in Tumors.- VII. Identification of Plasmid and Chromosomal Genes Involved in Oncogenicity.- VIII. Tumor Reversal.- 12 Mechanism of Disease Resistance.- I. Introduction.- II. Preformed Resistance Factors—Structural Features.- A. Cuticles.- B. Stomates.- C. Plant Hairs.- III. Preformed Resistance Factors—Preformed Antimicrobial Substances.- A. Cathechol and Protocatechuic Acid.- B. ?-Tomatine.- C. Unsaturated Lactones.- D. Sulfur Compounds (Leek Oils and Mustard Oils).- E. Extruded Materials.- F. Plant Glucanases and Chitinases.- IV. Infection-Induced Resistance Factors—Physical Features.- A. Periderm and Callose.- B. Gels and Tyloses.- C. Cell Wall Modifications.- V. Infection-Induced Resistance Factors—Chemical Features.- A. Hypersensitive Reaction.- B. Peroxidases.- C. Phenolic Compounds.- D. Catalase.- E. Glycosides.- F. Ethylene.- G. Histones.- H. Phytoalexins.- VI. The Dynamic and Coordinated Nature of Resistance.- 13 Induced Resistance.- I. Introduction.- II. Induced Resistance to Fungi.- III. Induced Resistance to Bacteria.- IV. Induced Resistance to Viruses.- V. Induced Resistance to Viroids.- VI. Some Features of Induced Resistance.- 14 Specificity in Plant-Pathogen Interactions.- I. Introduction.- II. Mechanisms of Specificity.- A. Hypersensitive Response.- B. Phytoalexins.- C. Selective Plant Toxins.- D. Common Antigens.- E. Recognition Phenomenon.- Some Useful Books.- References.