Orientador: Renate Krause-Sakate / Banca: Jorge Alberto Marques Rezende / Banca: Valdir Atsushi Yuki / Banca: Julio Massaharu Marubayashi / Banca: Marcelo Agenor Pavan / Banca: Edson Lopes Baldin / Resumo: As cultivares de pimentão (Capsicum annuum L.) são geralmente suscetíveis à infecção por vírus, destacando-se no Brasil espécies dos genêros Potyvirus, Begomovirus, Cucumovirus, Tobamovirus e Tospovirus, sendo que deste último gênero predominam as espécies GRSV (Groundnut ring spot virus) e TCSV (Tomato chlorotic spot virus) no Estado de São Paulo. Devido ao amplo número de hospedeiros infectados pelos tospovírus e a ineficiência do controle químico na transmissão do vírus pelo vetor (tripes), é imprescindível o manejo integrado da doença. Diante disso, o objetivo deste trabalho foi avaliar o uso do defensivo químico piraclostrobina + metiram (P +M) como forma alternativa de controle dos tospovírus GRSV e TCSV no híbrido de pimentão Dahra RX, avaliando-se a produção quantitativa e qualitativa da planta e a influência do produto sobre a quantidade relativa de partículas virais do GRSV. Três experimentos foram realizados paralelamente, sendo dois em campo, dos quais um recebeu pré-tratamento pela aplicação de P + M (4 g. l -1) na bandeja. No experimento em estufa, o pré-tratamento consistiu pela aplicação de P + M (4 g. l -1) no transplante em 50% das plantas (total de 120 plantas). Os tratamentos foram constituídos da inoculação do vírus de forma natural no campo e via extrato vegetal em estufa aos 0, 15, 30, 45 dias após o transplantio (DAT) com ou sem aplicação de P + M (4.0 g. l -1) durante o cultivo. A infecção pelos vírus GRSV/TCSV foi confirmada por PTA- ELISA e a concentração viral via qPCR foi avaliada para as plantas cultivadas em estufa. No experimento realizado em estufa obteve-se 98% das plantas infectadas quando inoculadas via extrato vegetal, enquanto 25% das plantas no campo foram infectadas naturalmente por GRSV ou TCSV, porém com predominância do GRSV. A infecção de plantas deste híbrido pelas espécies GRSV e TCSV até os 45 dias ... / Abstract: The cultivars of pepper (Capsicum annuum L.) are usually susceptible to virus infection, especially by the species of the genus Potyvirus, Begomovirus, Cucumovirus, Tobamovirus and Tospovirus in Brazil. GRSV (Groundnut ring spot virus) and TCSV (Tomato chlorotic spot virus) are the main tospovirus species in São Paulo state. Due to the large host circle of tospovirus and inefficient chemical vector control (thrips) in the virus transmission, the integrated management of the disease is essential. Thus, the aim of this study was to evaluate the use of chemical defensive Pyraclostrobin + Metiram (P + M) as an alternative form of control of tospoviruses GRSV and TCSV in the pepper hybrid Dahra RX, assessing the quantitative and qualitative production of the plant and the product's influence on the concentration of viral particles of GRSV. Three experiments were carried out in parallel, two in the field, one which received pre-treatment by applying P + M (4 g. L -1) on the tray. In the greenhouse experiment, the pre-treatment consisted by application of P + M (4 g. L -1) in the transplanting of 50% of the plants (total 120 plants). The treatments consisted of inoculation of the virus naturally in the field and sap transmission in greenhouse at 0, 15, 30, 45 days after transplanting (DAT) with application or not of P + M (4.0 g. L -1) during cultivation. Infection by GRSV / TCSV virus was confirmed by PTA-ELISA and virus concentration was evaluated by qPCR for plants in greenhouse. In the greenhouse experiment was obtained 98% of infected plants sap transmitted, while 25% of the plants in the field were naturally infected by GRSV or TCSV, but with predominance of GRSV. Infection of plants of this hybrid by GRSV and TCSV until 45 days after transplantation caused considerable damage in the quality and quantity of fruits produced. The use of the product during the cultivation of the hybrid did not affect ... / Doutor

Shuk-man Chow. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 171-186). / Abstracts in English and Chinese. / Thesis committee --- p.i / Statement --- p.ii / Abstract --- p.iii / Acknowledgement --- p.viii / General abbreviations --- p.x / Abbreviations of chemicals --- p.xi / List of figures --- p.xii / List of Tables --- p.xiii / Table of contents --- p.xv / Chapter 1. --- Literature review / Chapter 1.1. --- General introduction to rice disease --- p.1 / Chapter 1.1.1. --- Pathogenesis of Bacterial Leaf Blight (BLB) --- p.1 / Chapter 1.1.2. --- Pathogenesis of rice blast --- p.2 / Chapter 1.1.3. --- Control of rice diseases --- p.3 / Chapter 1.2. --- Plant defense mechanisms --- p.4 / Chapter 1.2.1. --- Basal resistance in plants --- p.4 / Chapter 1.2.2. --- Wound induced defense response --- p.5 / Chapter 1.2.3. --- Pathogen induced host defense response --- p.6 / Chapter 1.3. --- Structure of R gene products --- p.7 / Chapter 1.4. --- Recognition between R and Avr proteins in rice --- p.8 / Chapter 1.5 --- Current knowledge on Xa resistance and AvrXa avirulence protein --- p.9 / Chapter 1.6 --- Current knowledge on Pi resistance and AvrPi avirulence protein --- p.10 / Chapter 1.7 --- Pathogen induced signal transduction cascade --- p.12 / Chapter 1.7.1. --- R gene mediated signal transduction cascade --- p.12 / Chapter 1.7.2. --- Signal events of G-protein activation --- p.12 / Chapter 1.7.3. --- Signaling events for the accumulation of Ca2+ in cytosol --- p.13 / Chapter 1.7.4. --- Signaling events for oxidative burst --- p.14 / Chapter 1.7.5. --- MAPK cascade in defense signaling --- p.15 / Chapter 1.7.6. --- Transcriptional regulation of disease resistance related genes --- p.16 / Chapter 1.7.7. --- Translational regulation of disease resistance related genes --- p.17 / Chapter 1.8. --- Defense responses and defense related genes --- p.19 / Chapter 1.8.1. --- Pathogenesis related (PR) proteins --- p.20 / Chapter 1.8.2. --- Phytoalexins --- p.21 / Chapter 1.9. --- Disease resistance related genes common between rice blast and BLB resistance --- p.22 / Chapter 1.10. --- SA induced signal transduction pathway in rice --- p.23 / Chapter 1.11. --- Important tools facilitating the identification of disease resistance related genes from BLB resistant rice lines --- p.24 / Chapter 1.12. --- Hypothesis --- p.26 / Chapter 1.13. --- Project objective --- p.26 / Chapter 2. --- Materials and Methods --- p.27 / Chapter 2.1. --- Plant Materials --- p.27 / Chapter 2.2. --- Pathogen Inoculation --- p.27 / Chapter 2.3. --- RNA extraction --- p.29 / Chapter 2.4. --- Denaturing gel electrophoresis --- p.29 / Chapter 2.5. --- Subtraction libraries construction --- p.30 / Chapter 2.5.1. --- Cloning of disease resistance related genes --- p.32 / Chapter 2.5.1.1. --- pBluescript II KS (+) T-vector preparation --- p.32 / Chapter 2.5.1.2. --- Ligation --- p.32 / Chapter 2.5.1.3. --- Transformation --- p.32 / Chapter 2.5.1.4. --- Colony picking --- p.33 / Chapter 2.5.1.5. --- PCR amplification of DNA inserts --- p.33 / Chapter 2.5.1.6. --- Purification of PCR products --- p.34 / Chapter 2.6. --- Gene chips printing --- p.34 / Chapter 2.7. --- Probes synthesis and gene chips hybridization --- p.35 / Chapter 2.8. --- Standard-RNAs synthesis --- p.35 / Chapter 2.9. --- Data collection and analysis --- p.36 / Chapter 2.10. --- Sequencing --- p.36 / Chapter 2.11. --- cDNA synthesis --- p.37 / Chapter 2.12. --- RT-PCR --- p.38 / Chapter 2.13. --- DNA gel electrophoresis --- p.39 / Chapter 3. --- Results --- p.58 / Chapter 3.1. --- Construction of BLB gene chips --- p.58 / Chapter 3.1.1. --- Preparation of cDNA clones for gene chips construction --- p.58 / Chapter 3.1.2. --- Purification of PCR products on microtiter plate --- p.59 / Chapter 3.1.3. --- Gene chips construction --- p.59 / Chapter 3.1.4. --- DNA immobilization --- p.62 / Chapter 3.1.5. --- Probe synthesis --- p.62 / Chapter 3.1.6. --- Gene chip analysis --- p.65 / Chapter 3.1.6.1. --- Scanning --- p.65 / Chapter 3.1.6.2. --- Data analysis --- p.65 / Chapter 3.2. --- "Identification of disease resistance related genes commonly regulated by Xa2, Xal2 and Xal4 BLB resistance loci" --- p.70 / Chapter 3.2.1. --- "Signal perception, transduction and regulatory elements" --- p.71 / Chapter 3.2.1.1. --- Proteins involved in reversible phosphorylation cascade --- p.71 / Chapter 3.2.1.2. --- Proteins potentiate signal transduction through specific protein-protein interaction --- p.72 / Chapter 3.2.1.3. --- Other signal transduction components --- p.73 / Chapter 3.2.2. --- Transcriptional and translational regulatory elements --- p.74 / Chapter 3.2.2.1. --- Proteins involved in transcriptional regulation --- p.74 / Chapter 3.2.2.2. --- Proteins involved in post-transcriptional regulation --- p.75 / Chapter 3.2.2.3. --- Proteins involved in translational regulation --- p.76 / Chapter 3.2.3. --- "Oxidative burst, stress, apoptotic related genes" --- p.77 / Chapter 3.2.3.1. --- Stress related proteins --- p.77 / Chapter 3.2.3.2. --- Proteins involved in induction of oxidative burst --- p.78 / Chapter 3.2.3.3. --- PR proteins --- p.79 / Chapter 3.2.3.4. --- Proteolysis related proteins --- p.79 / Chapter 3.2.4. --- Cell maintenance and metabolic genes --- p.80 / Chapter 3.2.4.1. --- Antioxidant --- p.80 / Chapter 3.2.4.2. --- Metabolic genes --- p.81 / Chapter 3.2.4.3. --- Molecular chaperone --- p.82 / Chapter 3.2.4.4. --- Cell cycle regulators --- p.82 / Chapter 3.2.4.5. --- Cell wall maintenance --- p.83 / Chapter 3.2.4.6. --- Proteins involved in protein transport --- p.83 / Chapter 3.2.5. --- Unclassified/others --- p.84 / Chapter 3.3. --- Expression analysis of disease resistance related genes --- p.88 / Chapter 4. --- Discussion --- p.141 / Chapter 4.1. --- Differential expression of disease resistance candidates --- p.141 / Chapter 4.2. --- Disease resistance signal transduction components --- p.143 / Chapter 4.2.1. --- Reversible phosphorylation cascade --- p.143 / Chapter 4.2.2. --- Signal transduction potentiated by protein-protein interaction --- p.144 / Chapter 4.3. --- Other signaling molecules --- p.145 / Chapter 4.3.1. --- PRL1-interacting factor G --- p.145 / Chapter 4.3.2. --- Vacuolar-type H+-ATPasen subunit G --- p.146 / Chapter 4.4. --- Regulation of expression of disease resistance candidates --- p.146 / Chapter 4.4.1. --- Transcriptional regulation of disease resistance related genes --- p.146 / Chapter 4.4.1.1. --- G-box binding protein --- p.147 / Chapter 4.4.1.2. --- MYB TF --- p.147 / Chapter 4.4.2. --- Post-transcriptional modification of disease resistance candidates --- p.148 / Chapter 4.4.2.1. --- RNA splicing factor --- p.148 / Chapter 4.4.2.2. --- Glycine rich RNA binding proteins --- p.149 / Chapter 4.4.3. --- Translational regulation of disease resistance related genes --- p.149 / Chapter 4.5. --- Induction of oxidative burst --- p.150 / Chapter 4.6. --- PR proteins --- p.151 / Chapter 4.7. --- Cell maintenance --- p.152 / Chapter 4.7.1. --- Protein folding --- p.152 / Chapter 4.7.2. --- Protein degradation --- p.153 / Chapter 4.7.3. --- ROS scavenging --- p.154 / Chapter 4.7.4. --- Regulation of cell cycle --- p.154 / Chapter 4.8. --- "Confirmation and profiling of disease resistance related candidates commonly regulated in Xa2, Xal2 and Xal4 BLB resistance NILs at different time points" --- p.155 / Chapter 4.8.1. --- Basal resistance related genes --- p.156 / Chapter 4.8.2. --- General disease resistance related genes --- p.161 / Chapter 4.8.3. --- Pathogen responsive genes --- p.164 / Chapter 4.8.4. --- Prediction of novel genes functions --- p.168 / Chapter 4.9. --- Future prospect --- p.169 / Chapter 4.10. --- Conclusion --- p.169 / References --- p.171 / Appendix --- p.187

Au Yeung, Wan Kin. / "August 2011." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 89-103). / Abstracts in English and Chinese. / Thesis committee --- p.i / Statement --- p.ii / Abstract --- p.iii / Acknowledgements --- p.v / General abbreviations --- p.vi / Abbreviations of chemicals --- p.vii / List of figures --- p.ix / List of figures in Appendix VI --- p.xii / List of tables --- p.xiv / Table of Contents --- p.xv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The significance of studying rice disease resistance --- p.1 / Chapter 1.1.1 --- Economic importance of rice --- p.1 / Chapter 1.1.2 --- Diseases caused by pathogens virulent to rice --- p.1 / Chapter 1.1.2.1 --- Bacterial leaf blight diseases --- p.1 / Chapter 1.1.2.2 --- Fungal blast diseases --- p.2 / Chapter 1.1.3 --- Approach to enhance resistance of crops towards pathogens --- p.2 / Chapter 1.2 --- Literature review on plant immunity system --- p.3 / Chapter 1.2.1 --- Pathogen associated molecular patterns (PAMP) and PAMP -triggered immunity (PTI) --- p.4 / Chapter 1.2.2 --- Pathogen effectors and effector-triggered immunity (ETI) --- p.5 / Chapter 1.2.3 --- Roles of phytohormones in plant defense responses --- p.6 / Chapter 1.2.4 --- G protein signaling and plant defense responses --- p.9 / Chapter 1.3 --- Literature review on FK506 binding proteins (FKBPs) --- p.10 / Chapter 1.4 --- Background information of this study - origin of the clone chosen for study in this project --- p.11 / Chapter 1.5 --- Hypothesis and Objectives --- p.12 / Chapter Chapter 2 --- Materials and Methods --- p.13 / Chapter 2.1 --- Materials --- p.13 / Chapter 2.1.1 --- "Plants, bacterial strains and vectors" --- p.13 / Chapter 2.1.2 --- Chemicals and Regents --- p.18 / Chapter 2.1.3 --- Commercial kits --- p.18 / Chapter 2.1.4 --- Primers and Adaptors --- p.19 / Chapter 2.1.5 --- Equipments and facilities used --- p.23 / Chapter 2.1.6 --- "Buffer, solution, gel and medium" --- p.23 / Chapter 2.2 --- Methods --- p.24 / Chapter 2.2.1. --- Bacterial and yeast cultures --- p.24 / Chapter 2.2.2 --- Plant growth conditions and treatments --- p.25 / Chapter 2.2.2.1 --- Surface sterilization of J. thaliana seeds --- p.25 / Chapter 2.2.2.2 --- Environmental conditions of A. thaliana for germination of seeds and growing of seedlings --- p.26 / Chapter 2.2.2.3 --- Environmental conditions of A. thaliana for growing of plants --- p.26 / Chapter 2.2.2.4 --- Pathogen inoculation test of A. thaliana with Pst DC3000 --- p.27 / Chapter 2.2.3 --- Cloning and subcloning of OsFKBP 12 and OsUCCl --- p.27 / Chapter 2.2.3.1 --- Sub-cloning of OsFKBP12 to pGEX-4T-l and pMAL-c2 --- p.27 / Chapter 2.2.3.2 --- Cloning of OsUCCl to pGEX-4T-l --- p.29 / Chapter 2.2.4 --- "DNA, RNA and protein extractions" --- p.29 / Chapter 2.2.4.1 --- Plasmid extraction from bacterial cells --- p.29 / Chapter 2.2.4.2 --- Genomic DNA extraction from plant through CTAB method --- p.29 / Chapter 2.2.4.3 --- RNA extraction from plant tissues --- p.30 / Chapter 2.2.4.4 --- Protein extraction from plant tissues --- p.31 / Chapter 2.2.4.5 --- Fusion protein extraction from E. coli --- p.31 / Chapter 2.2.5 --- Western blot analyses --- p.32 / Chapter 2.2.5.1 --- Western blot analysis of GST tag and MBP tag fusion proteins --- p.32 / Chapter 2.2.5.2 --- Western blot analysis native OsYchFl proteins --- p.33 / Chapter 2.2.6 --- Real-time PCR study --- p.33 / Chapter 2.2.6.1 --- cDNA synthesis --- p.33 / Chapter 2.2.6.2 --- Real-time PCR --- p.34 / Chapter 2.2.7 --- Yeast two hybrid --- p.35 / Chapter 2.2.7.1 --- Screening of OsFKBP 12 interaction protein partners by yeast mating --- p.35 / Chapter 2.2.7.2 --- Identification of positive interacting protein partners by extracting DNA plasmid from yeast --- p.35 / Chapter 2.2.7.3 --- Re-transformation of pGBKTl-OsFKBP 12 with their interacting partner clones into yeast (AH 109) by co-transformation --- p.36 / Chapter 2.2.8 --- In vitro pull down assay of OsFKBP 12 with their putative protein interacting partner --- p.36 / Chapter 2.2.8.1 --- In vitro pull down of native OsYchFl by MBP-His-OsFKBP12 --- p.36 / Chapter 2.2.8.2 --- In vitro pull down of GST-AtYchF 1 by MBP-His-OsFKBP12 --- p.37 / Chapter 2.2.8.3 --- In vitro pull down of MBP-His-OsFKBP12 by GST-OsUCCl --- p.37 / Chapter 2.2.8.4 --- In vitro pull down of MBP-His-OsFKBP12 by GST-OsYchFl G domain --- p.38 / Chapter 2.2.9 --- GTPase assay ofOsYchF with OsFKBP12 --- p.38 / Chapter 2.3.0 --- Phylogenetic analysis and sequence alignment --- p.39 / Chapter Chapter 3 --- Results --- p.40 / Chapter 3.1 --- Identification of OsFKBP 12 encoding a FKBP (FK506 binding protein)-domain containing protein in Oryza sativa (rice) --- p.40 / Chapter 3.2 --- OsFKBP12 was down-regulated in the pathogen-inoculated Xal4 rice line CBB14 --- p.47 / Chapter 3.3 --- Ecotpic expression of OsFKBP 12 repressed the expression of defense marker genes in transgenic A. thaliana --- p.50 / Chapter 3.4 --- Expressing OsFKBP 12 in transgenic A. thaliana enhanced the susceptibility to the bacterial pathogen Pst DC3000 --- p.54 / Chapter 3.5 --- OsFKBP 12 protein interacted with a putative defense-related G-protein and a copper binding protein --- p.57 / Chapter 3.6 --- "OsFKBP 12 protein interacted with the G domain of defense-related G protein, OsYchFl" --- p.69 / Chapter 3.7 --- OsFKBP 12 protein enhanced the in vitro phosphate release of OsYchFl --- p.72 / Chapter Chapter 4 --- Discussion --- p.74 / Chapter 4.1 --- The identification and characterization of OsFKBP 12 --- p.74 / Chapter 4.2 --- Expression pattern of OsFKBP 12 upon biotic stress in bacterial blight resistant near isogenic line (NIL) --- p.75 / Chapter 4.3 --- OsFKBP 12 repressed the expression of SA-regulated defense marker genes when ectopically expressed in A. thaliana --- p.75 / Chapter 4.4 --- Ectopic expression of OsFKBP 12 enhanced susceptibility towards Pst DC3000 in transgenic A. thaliana --- p.76 / Chapter 4.5 --- The interacting partners of OsFKBP 12 in relation to plant defense response --- p.78 / Chapter 4.6 --- The specific biochemical interaction of OsFKBP 12 with OsYchFl --- p.80 / Chapter 4.7 --- Future perspectives --- p.85 / Chapter Chapter 5 --- Conclusion --- p.87 / References --- p.89 / Appendix --- p.104

Orientador: Antonio Carlos Maringoni / Coorientador: Tadeu Antônio Fernandes da Silva Júnior / Banca: Ricardo Gioria / Banca: Renate Krause Sakate / Resumo: O pimentão é uma hortaliça com grande apreciação no Brasil, tendo elevada importância no mercado de condimentos, temperos e conservas. O Estado de São Paulo é o principal produtor desta hortaliça, com produção aproximada de 85.000 toneladas na safra 2010. Dentre os principais problemas fitossanitários da cultura do pimentão, destaca-se a mancha bacteriana, causada por espécies de Xanthomonas spp. A doença pode ocasionar perdas substanciais na produtividade da cultura, especialmente em períodos de elevadas pluviosidade e temperatura, além da baixa eficácia de controle com produtos químicos, como fungicidas cúpricos. Em vista do exposto, o objetivo do presente trabalho foi caracterizar 59 isolados de Xanthomonas spp. de pimentão obtidos de diferentes regiões produtoras do Brasil, através da utilização de técnicas bioquímicas/fisiológicas, moleculares e verificar a sensibilidade in vitro dos isolados aos sulfatos de cobre e zinco e suas misturas. Para os ensaios bioquímicos/fisiológicos, foram realizados os testes de reação diferencial de Gram, solubilidade em KOH a 3%, hidrólise de amido, atividade pectinolítica e a utilização de 13 fontes de carbono, em microplacas GN2 da Biolog®. A identificação molecular foi realizada através de reações de PCR com os iniciadores específicos para X. euvesicatoria, X.vesicatoria, X. gardneri e X. perforans. A sensibilidade in vitro dos isolados aos sulfatos de cobre e zinco foi avaliada nas concentrações de 50, 100, 200 e 400 μg.mL-1, além da mistura de 50% de cada um dos produtos, nas mesmas concentrações finais no meio de cultura PSA. Com base nos resultados dos testes bioquímicos/fisiológicos e moleculares (PCR) com iniciadores específicos revelaram a prevalência de X. euvesicatoria em pimentão no Brasil. Todos os isolados avaliados foram resistentes ao sulfato de zinco e 85% deles foram resistentes ao ... / Abstract: Pepper is a vegetable with great appreciation in Brazil and high importance for the market of condiments, spices and canned goods. Sao Paulo state is the main producer of pepper in Brazil with almost 85.000 ton in 2010. One of the most important phytosanitary problems for this crop is the bacterial spot, caused by species of Xanthomonas spp. This disease can cause crop productivity losses, especially during periods of high rainfall and temperature, in addition to the low efficacy of chemicals, as copper fungicides. In this study, we characterized 59 strains of Xanthomonas spp. associated with bacterial spot from different producing regions of Brazil, using biochemical/physiological and molecular techniques, and evaluated the in vitro sensitivity of strains to copper and zinc sulfates. For the biochemical/physiological assays, Gram staining, KOH string test, starch hydrolysis, pectinolytic activity and the utilization of 13 carbon sources on Biolog® GN2 microplates were performed. Molecular characterization was performed by PCR with specific initiators for X. euvesicatoria, X.vesicatoria, X. gardneri and X. perforans. In vitro sensitivity of strains to copper and zinc sulfates was evaluated at concentrations 50, 100, 200 and 400 μg.mL-1, together with the mixing of the chemicals, in the same final concentration in culture medium. Based on starch hydrolysis and pectinolytic activity results, strains were divided in two distinct groups: X. vesicatoria with X. perforans (positive pectinolytic and amylolytic activities) and X. euvesicatoria with X. gardneri (negative pectinolytic and amylolytic activities). PCR and carbon sources utilization results revealed the prevalence of X. perforans on pepper in Brazil. All strains were resistant to zinc sulfate and 85% to copper sulfate. The mixing of the chemicals at concentration of 400 μg.ml-1 inhibited the growth of all strains assessed. / Mestre

Thesis (Ph.D. Agriculture (Horticulture)) -- University of Limpopo, 2012 / High yield losses in various crops due to plant-parasitic nematodes are associated with high initial nematode population densities (Pi). Uses of synthetic nematicides to reduce Pi were dependent on the physiological effect of materials on the protected crops, resulting into the coining of pre-emergent and post-emergent nematicides. Crude extracts of wild cucumber (Cucumis myriocarpus) fruit consistently reduced nematode population densities of the southern root-knot nematode (Meloidogyne incognita) when used as a post-emergent bio-nematicide. The purpose of this study was to investigate the compatibility of crude extracts of C. myriocarpus fruit when used as a pre-emergent bio-nematicide on germination and emergence of commercially important dicotyledonous and monocotyledonous crops using empirical tests and computer-generated models. Studies were conducted over a period of three years to assess the effects of this material on growth of various seedlings. Seven treatments comprising crude extracts of C. myriocarpus fruit (0, 2.5, 5, 7.5, 10, 12.5 and 15 g/pot) and test solutions (0, 25, 50, 75, 100, 125 and 150 g/ℓ distilled water) were used for emergence and germination in initial studies. Generally, 18 days after the treatments, variables measured and levels of crude extracts of C. myriocarpus fruit had negative quadratic relationships, which suggested that they had density-dependent growth responses. Subsequent studies were conducted using three selected crops each from the families Alliaceae, Gramineae and Solanaceae under greenhouse conditions, each with reduced concentration of 10 treatments (0, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00 and 2.25 g material/pot). Using variables of various organs and crops, significant means were subjected to the Curve-fitting Allelochemical Dosage Response (CARD) computer model, which was characterised by six biological indices, viz. threshold stimulation (Dm), xli saturation level (Rh), 0% inhibition (D0), 50% inhibition (D50), 100% inhibition (D100) and transformation level (k). The model demonstrated that the responses of the three crops from each family when regressed to dosages of crude extracts of C. myriocarpus fruit exhibited the density-dependent growth patterns, characterised by responses that included stimulation, saturation and inhibition. The integrated sensitivities (Σk) of the tested crops to crude extracts of C. myriocarpus fruit ranged from Σk = 9 to Σk = 51, with eggplant (Solanum melongena) and sorghum (Sorghum bicolor) being the most sensitive, while tomato (Solanum lycopersicum) was the least sensitive. Using the data depicting the stimulation range from CARD model, viz. (Dm), which is a threshold stimulation dosage and (Rh), which is a saturation dosage, mean dosage stimulation response (MDSR) was determined for chive (Allium schoenoprasum), leek (Allium ampeloprasum), onion (Allium cepa), maize (Zea mays), millet (Panicum miliaceum), sorghum, eggplant, pepper (Capsicum annum) and tomato as being 1.19, 0.68, 0.45, 1.13, 0.86, 1.12, 0.74, 1.11, and 0.53 g, respectively. These MDSR values are dosages which when applied for respective crops at direct seeding would not affect germination or emergence. MDSR values were validated for onion, millet and tomato, resulting in approximately 100% suppression of nematodes in all three test crops. In contrast, 100% emergence occurred in millet and tomato, while the validated MDSR reduced emergence on onion by 15%, which confirmed the sensitivity of this crop to crude extracts of C. myriocarpus fruit. In conclusion, crude extracts of C. myriocarpus fruit have the potential for use as pre-emergent bio-nematicide in suppression of plant-parasitic nematodes in various crops.

No description available.

No description available.

Phoma medicaginis is a necrotrophic fungal pathogen, commonly found infecting Medicago truncatula and M. sativa in temperate regions of Australia. To identify, characterize and differentiate eight P. medicaginis isolates from Western Australia, morphological phenotypes and five gene regions (actin, â- tubulin, calmodulin, internal transcribed spacer, translation elongation factor 1-á) were examined. Sequence comparisons showed that specimens isolated from M. truncatula in Western Australia formed a group that was consistently different from, but closely allied to, a P. medicaginis var. medicaginis type specimen. Characterization of three P. medicaginis genotypes showed that all exhibited a narrow host range, causing disease only in M. sativa and M. truncatula among eight commonly cultivated legume species sampled. Infection of 85 M. truncatula accessions showed a continuous distribution in disease phenotypes, with the majority of accessions susceptible. Differences in disease phenotypes suggest that M. truncatula harbours specific and diverse sources of resistance to individual P. medicaginis genotypes. To characterize the genetic basis of resistance to P. medicaginis two F2 populations derived from crosses between the resistant accession SA27063 and the susceptible accessions SA3054 and A17 were phenotyped for disease symptoms. Highly significant recessive QTLs for resistance to P. medicaginis OMT5 were identified in each mapping population. In SA27063 x A17 a QTL named resistance to the necrotroph Phoma medicaginis one (rnpm1) was identified on the short arm of LG4. In SA27063 x SA3054 a QTL (rnpm2) was identified on the long arm of LG8. Further fine mapping of the areas surrounding the QTLs is underway to identify the genes underlying rnpm1 and rnpm2. Examination of the recombination frequencies between genetic markers on the long arms of chromosomes 4 and 8 in the SA27063 x A17 cross revealed an apparent genetic linkage between these chromosomes. Subsequent analysis of other crosses showed this unexpected linkage relationship is characteristic for genetic maps derived from A17. Furthermore F1 individuals derived from crosses involving A17 showed 50% pollen viability or less. This semisterility and the unexpected linkage relationships provide good evidence for a reciprocal translocation in A17 between chromosomes four and eight. The implications of the distinctive chromosomal rearrangement in A17 on genetic mapping, genome sequencing and comparative mapping are discussed. The Mt16kOLI1plus microarray was used to identify transcriptional changes in M. truncatula expressed in defence against P. medicaginis. Three-hundred-and-thirty-four differentially expressed transcripts showed a change of two-fold or more in either the resistant or susceptible interaction, and most of the Phoma-regulated genes could be assigned to functional categories which have been reported to be involved in plant defence responses. RT-qPCR and HPLCUV confirmed involvement of the octadecanoid and phenylpropanoid pathways in response to P. medicaginis infection. Faster induction of lipoxygenase genes and constitutively higher levels of certain phenolic metabolites were observed in resistant plants.

Includes bibliographical references (leaves 241-25). Aims to evaluate sampling procedures; assess the extent and magnitude of yield loss caused by Pratylenchus neglectus; assess the population dynamics of Pratylenchus neglectus in cereals; determine whether resistance occurs in field crops; and, assess whether variation occurs between geographically isolated species of Pratylenchus neglectus

Errata attached to inside front cover. Bibliography: leaves [156-188]