封面 List of Contents 1.Abstract 1.1 Abstract(in English) 1.2 Abstract(in Chinese) 2.Introduction 2.1 Plant-bacteria Interactions 2.2 Genes involved in bacterial pathogenesis of plants 2.2.1 hrp genes as key genes in the control of plant-bacteria interactions 2.2.2 avr genes as determinants of host specificity in pathogenic bacteria 2.2.3 Other genes or systems required for pathogenicity 2.3 2.3.1 Citrus canker 2.3.2 Xanthomonas campestris pv.citri 2.3.3 Genetic basis of X.campestris pv.citri 2.3.4 Pathogenic mutants of X.campestris pv.citri 3.Materials 3.1 Bacterial and plasmid 3.2 Plants 3.3 Chemicals and enzymes 3.4 Antibiotics 3.5 Media 3.6 Buffer and Solutions 4.Methods 4.1 Bacterial growth conditions 4.2 Electroporation 4.3 Transposition mutagenesis 4.4 Pathogenicity assays 4.5 Hypersensitive reaction test 4.6 DNA manipulation 4.7 Southern hybridization 4.8 Construction of genomic libraries 4.9 DNA sequences analyses 4.10 Phoshoglucose isomerase(PGI)enzyme assay 4.11 Construction of promoter fusion and β-glucuronidase assay 5.Results 5.1 5.1.1 Induction of hypersensitive response on nonhosts 5.1.2 Isolation and identification of hrp from X.campestris pv.citri 5.1.3 Analysis of hrp locus 5.1.4 Regulation of hryX locus 5.2 5.2.1 Isolation and characterization of a nonpathogenic mutant XT906 5.2.2 Nonpathogenic mutant XT906 did not elicite HR on bean 5.2.3 Isolation and identification of a DNA region required for growth oncitrus and pathogenicity 5.2.4 The nonpathogenic XT9006 mutant resulted in the mutation of PGI 5.2.5 REgulation of pgi and hrpX gene expression 6.Discussion 6.1 6.1.1 The mutationof hrpX in X. campestris pv.citri does not affect toproduce extracellular polysaccharide 6.1.2 The hrpX of X.campestris pv.citri was a member of AraC regulatoryprotein family 6.1.3 The expression of hrpX gene in X. campestris pv.citri was dependenton nutritional conditions 6.1.4 The hrp genes and host specificity inf the plant-microbe interaction 6.2 6.2.1 PGI is an enzyme at fructose metabolism pathway of X.campestris 6.2.2 PGI was essential for cell growth in planta upon infection 6.3 6.4 7.Conclusion 8.References 9.Appendixes 9.1 Abbreviations 9.2 Tables 9.3 Figures
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