声明
论文说明
Acknowledgements
Contents
List of Figures
List of Tables
List of Abbreviations
ABSTRACT
摘要
Chapter 1 General Introduction
1.1 Background information
1.2 Project goals
1.3 Specmc objectives
Chapter 2 Literature Review
2.1 Nomenclature and classification of the pathogen
2.2 Pathogenicity determinants of V.dahliae
2.2.1 Infectious structures
2.2.2 Cell wall degrading and hydrolytic enzymes
2.2.3 Phytotoxins and ellcitors
2.3 Plant defense responses
2.3.1 Phenylpropanold metabolism and cell wall fortificcatiOn
2.3.2 Carbohydrate metabollsm and osmoregulation
2.3.3 Induction of pathogenesis-related(PR)proteins
2.3.4 ROS in signal transduction
2.3.5 Nitric oxide(NO)in signal transduction
2.3.6 Network and interplay of signaling pathways
2.4 Management of Verticillium wilt
2.4.1 Biological control
2.4.2 Organic amendments
2.4.3 Resistant germplasm
2.5 Brassinosteroids(BRs)
2.5.1 BR signaling in plants
2.5.2 Ameliorative role of BRs in biotic stresses
2.5.3 Mechanism of brassinosteroid mediated stress tolerance
Chapter 3 Effect of Verticillium dahliae toxin (Vd toxin)on cell structure,plantmorphology and biochemical characteristics of upland cotton
3.1 Materials and methods
3.1.1 Fungus growth and toxin preparation
3.1.2 Plant growth,treatment conditions and measurement of basic nutrition solution(BNS)uptake
3.1.3 Assessment of root dehydmgenase activity
3.1.4 Measurement of chlorophyll fluorescence
3.1.5 Determination of lipid peroxidation,SOD activity and contents of reduced ascorbate(ASA)and reduced glutathione(GSH)
3.1.6 Determining the plant growth parameters and root architecture
3.1.7 Scanning electron microscopy (SEM) and transmission electron microscopy(TEM)
3.1.8 Statistical analysis
3.2 Results
3.2.1 Plant growth and root dehydrogenase activity
3.2.2 Ultrastructure changes in leaf and root cells
3.2.3 SEM observations of root tips and leaf epldermis
3.2.4 Basic nutrition solution(BNS)uptake and chlorophyll fluorescence(Fv/Fm)
3.2.5 Lipid peroxidation and SOD activity
3.2.6 Contents of reduced glutathione(GSH)and reduced ascorbate(ASA)
3.2.7 Effect of Vd toxin on root architecture and plant growth parameters
3.3 Discussion
3.4.Conclusion
Chapter 4 Role of brassinosteroids to alleviate the negative effects of Vd toxin on cotton callus growth
4.1 Materials and methods
4.1.1 Plant material,toxin preperation and treatment conditions
4.1.2 Determination of chlorophyll and carotenoids contents
4.1.3 Measurement of secondary metabolism-related enzymes activities
4.1.4 Quantification of flavonoids,total phenols,soluble sugars and protein
4.1.5 Measurement of DNA damage through single cell gel electrophoresis assay(Comet assay)
4.1.6 Tissue processing for transmission electron microscope(TEM)
4.1.7 Statistic analysis
4.2 Resuits
4.2.1 Effect of EBR on callus growth
4.2.2 EBR induced tolerance to Vd toxin
4.2.3 Chlorophyll and carotenoids contents
4.2.4 Activites of secondary metabollsm related enzymes under Vd toxin stress
4.2.5 Flavonoids,total phenols,soluble sugars and protein
4.2.6 DNA damage in cotton callus
4.2.7 Ultrastructural changes under Vd toxin and ameliorative effects of EBR
4.3 Discussion
4.4 Conclusion
Chapter 5 Brassinosteroids attenuated Verticillium wilt in upland cotton by modulating the carbohydrates metabolism,plasma membrane ATPases and intracellular osmolytes
5.1 Materials and methods
5.1.1 Plant growth,toxin preparation and treatment conditions
5.1.2 Evaluation of plant wilting,photosynthesis,transpiration,SPAD and chlorophyll fluorescence
5.1.3 Determination of prollne,glycine-betaine and soluble sugar content
5.1.4 Determination of the enzymes activities involved in carbohydrate metabolism
5.1.5 Measurement of different ATPases activity
5.1.6 Statistical analysis
5.2 Results
5.2.1 EBR appllcation attenuated plant wilting
5.2.2 Activity of different ATPase in cotton leaves
5.2.3 Accumuiation of Intracellular osmolytes
5.2.4 Effect of Vd toxin and EBR on activities of enzymes involved in carbohydrate metabolism
5.2.5 Photosynthetic parameters,chlorophyll content and fluorescence
5.2.6 Root and shoot biomass
5.3 Discussion
5.4 Conclusion
Chapter 6 Understanding the physiological and biochemical basis of innate and brassinosteroid induced tolerance to Verticillium wilt in cotton leaves
6.1 Materials and methods
6.1.1 Plant material,growthr and treatment conditions
6.1.2 Measurement of superoxide radical(O2),hydrogen peroxide(H2O2),their histochemical detection and electrolyte leakage in cotton leaves
6.1.3 Determination of leaf osmotic potential and relative water contents
6.1.4 Measurement of the enzymes activitles involved in carbohydrate and secondary metabolism in cotton leaves
6.1.5 Determination of callose and lignin content
6.1.6 Analysis of the activities of antioxidative enzymes
6.1.7 Dynamics of glutathione-s-transferase (GST), dehydroascorbate reductase(DHAR)and contents of non enzymatic antioxidants
6.1.8 Quantification of total phenol,DPPH activity,flavonoids and total soluble proteins
6.1.8 Statistical analysls
6.2 Results
6.2.1 H2O2/O2ˉaccumulation and electrolyte leakage in cotton leaves
6.2.2 Changes in leaf osmotic potential(OP)and relative water content(RWC)
6.2.3 Stem lignin and callose deposition
6.2.4 Changes in the activities of enzymes involved in carbohydrate metabolism(Al,SuSy,SPS)in cotton leaves
6.2.5 Activties of enzymes involved in secondary metabolism in catton leaves
6.2.6 Glutathione-s-transferase(GST),dehydroascorbate reductase(DHAR)and contents of phenols,flavonoids,soluble protein and non enzymatic antioxidants
6.2.7 Dynamics of antioxidative enzymes in cotton leaves
6.3 Discussion
6.4 Conclusion
Chapter 7 Genotypic differences in carbohydrate,secondary metabolism and antioxidative capacities in cotton root and amino acid contents in root exudates
7.1 Materials and Methods
7.1.1 Measurement of O2ˉand H2O2 contents, enzymes activities of carbohydrate,secondary metabolism and antioxidants,phenols,flavonoids and callose in cotton root
7.1.2 Plant material,growth,inoculum preparation and treatment conditons
7.1.3 EvalUation of disease resistance
7.1.4 Collection of root exudates and analysis of amino acids
7.1.5 In vitro activities of amino acid on the growth of V.dahliae
7.1.6 Statistical analysis
7.2 Results
7.2.1 H2O2 and O2ˉaccumulation in cotton roots
7.2.2 Root dehydrogenase activity and lipid peroxidation
7.2.3 Enzyme activities of carbohydrate metabolism in cotton roots
7.2.4 Activhies of enzymes involved in phenylpropanoid pathway(PAL,PPO,CAD,and SKDH)
7.2.5 Changes in the conrents of DPPH,flavonoids and callose in cotton root
7.2.6 Activities of antioxidative enzymes in cotton root
7.2.7 Glutathione dependent detoxification
7.2.8 Disease resistance evaluation and plant growth
7.2.9 Changes in the contents of amino acids in cotton root exudates
7.2.10 In vitro effects of amino acids on V. dahliae growth
7.3 Discussion
7.4 Conclusion
Chapter 8 Liquid chromatography mass spectroscopy(LC-MS)analysis reveal that phenolic compounds and endogenous pIant hormones
8.1 Materials and methods
8.1.1 Plant growth,inoculum preparation and treatment conditions
8.1.2 Evaluation of disease resistance,H2O2 accumulation and electrolyte leakage
8.1.3 Measurement of enzyme activities of phenylpropanoid pathway
8.1.4 Extraction of phenollc compounds and endogenous plant hormones
8.1.5 Liquid chromatography mass spectroscopy(LC-MS/MS)
8.1.6 Real-time quantitative PCR (qPCR)analysis
8.1.7 Statistical analysis
8.2 Results
8.2.1 Dynamics of PAL and CAD
8.2.2 Expression analysis of PAL and CAD through quantitative real time PCR(qPCR)
8.2.3 Patterns of phenolic compounds in cotton leaf and Vd toxin
8.2.4 Changes in the levels of endogenous plant hormones
8.2.5 Expression of genes involved in hormone synthesis
8.2.6 H2O2 accumulation and electrolyte leakage of detached cotton leaves
8.2.7 Effect of V.dahliae inoculation and EBR application on disease development,plant growth and fungus colonization
8.3 Discussion
8.4 Conclusion
References
List of Publications