Download or read book Regulation of Virulence in the Plant Pathogen Pseudomonas Syringae Pv Tomato DC3000 written by Hanh Ngoc Lam and published by . This book was released on 2014 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: The type III secretion system (T3SS) is required for virulence of the gram-negative plant pathogen Pseudomonas syringae pv. tomato DC3000 (DC3000) in tomato and Arabidopsis. The alternative sigma factor HrpL directly regulates expression of T3SS genes by binding to a short DNA sequence designated as the "hrp promoter". The ability of DC3000 to colonize plants, subdue multiple layers of plant defense and multiply in plant tissues relies on the activities carried out by the many T3SS regulon members (known collectively as hrp genes). Efforts to identify genes involved in pathogenicity were initiated over three decades ago. However, HrpL binding to hrp promoters has never been directly demonstrated and it is unclear if the list of HrpL-regulated genes is complete. The first goal of the research described here was to systemically and exhaustively identify HrpL-binding sites and likely hrp promoters in the DC3000 genome. Employing chromatin immuno-precipitation, coupled with high-throughput sequencing (ChIP-Seq) and transcription start site analysis (modified RNA-Seq), we found twenty sites representing novel hrp promoters. Using deletion analysis, we attempted to determine if the genes downstream from a subset of these promoters could be linked to virulence. However, the deletions did not affect the hypersensitive response or in planta growth of the resulting strains. Interestingly, many new HrpL regulon members appear to be unrelated to the T3SS (based on their annotations), and orthologs for some of these can be identified in non-pathogenic bacteria. The connection of these new HrpL regulon members to virulence is not obvious. The HrpL regulon is activated as a result of a chain of events, most of which are not well understood. It is known that RpoN, which controls the transcription of hrpL in DC3000, is required for virulence in several bacterial species. Motivated by the hypothesis that genes are coordinately regulated in order to serve a strategic purpose (e.g., virulence), our second goal was to look for other genes activated by RpoN in parallel with hrpL. RpoN ([sigma]54) requires specialized enhancer-binding proteins (EBPs) in order to activate transcription. This arrangement presumably allows the cell to respond to environmental signals by modifying the transcription of particular genes. Using ChIP-Seq and RNA-Seq, we identified candidate RpoN-dependent genes as well as genes that were differentially expressed under hrp-inducing conditions. This initial survey includes more than 200 likely RpoN-regulated genes involved in flagella biosynthesis, energy metabolism, nitrogen metabolism, transport and binding proteins, and small noncoding RNAs, as well as putative regulatory proteins and EBPs. Among the genes that were differentially regulated between hrp-inducing and repressing conditions, more than one dozen appear to be regulated by RpoN and are therefore potentially important in functions related to plant association or virulence.
Download or read book Iron Transport in Microbes Plants and Animals written by Günther Winkelmann and published by Wiley-VCH. This book was released on 1987 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first comprehensive treatise on iron transport in bacteria, fungi, plants, and animals summarizes the current state of knowledge on the subject.
Download or read book Environmental and Density dependent Modulation of Type III Secretion System Genes in Pseudomonas Syringae Pv Tomato DC30 written by and published by . This book was released on 2010 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pseudomonas syringae pathovar tomato strain DC3000 is a model bacterial plant-pathogen that utilizes a dedicated protein export apparatus, the type III secretion system (T3SS), to translocate virulence proteins called effectors directly into host cells. Because effectors suppress plant immune responses, activation of the T3SS is critical upon entry into the host. The P. syringae T3SS is controlled by the hrpRS-hrpL regulatory cascade, and is activated quickly by specific conditions. Different environmental stimuli have been reported to modulate T3SS gene expression in culture, however it is unclear how each signal affects hrpRS or hrpL. My objective was to identify how environmental variables activate or repress hrpRS or hrpL in Pst DC3000. To this aim, I created three T3SS::gusA transcriptional reporter strains by fusing a promoterless gusA after hrpRS, hrpL, and a downstream effector gene, avrPto in the chromosome of Pst DC3000. I then analyzed GUS activity of each reporter strain cultured under variable conditions. I verified that repression of Pst DC3000 T3SS genes in KB acts upstream of the hrpRS operon, and that this repression is relieved by overexpression of either hrpR or hrpS. Furthermore, I demonstrated that hrpRS, hrpL, and avrPto, are differentially regulated by pH and carbon sources, although all carbon source tested (including sugars, a sugar alcohol, glycerol, and organic acids) initially induced T3SS gene expression. Results of several assays suggest that quorum sensing may be involved in regulation of the T3SS in Pst DC3000. First, T3SS genes were optimally expressed when growth media contained carbon sources that promoted slower growth, and when bacteria were cultured at low cell densities. In addition, I show that a T3SS repressive signal accumulated in high cell density Pst DC3000 cultures. However, density-dependent repression of T3SS genes was independent of psyRI, which mediates quorum sensing by acyl homoserine lactones (AHLs), and T3SS gene expression was unaffected by addition of 3-oxo-C6 or C6 AHLs. In contrast, T3SS genes were repressed when another small molecule produced by P. syringae, the auxin IAA, is added to Pst DC3000 cultures. However the biological relevance of IAA as a T3SS repressing signal remains to be explored.
Download or read book Virulence of Pseudomonas Syringae Pv Tomato Strain DC3000 on Arabidopsis Thaliana written by Julie Zwiesler-Vollick and published by . This book was released on 2002 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pseudomonas Syringae Pathovars and Related Pathogens written by K. Rudolph and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 687 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last decade, research on Pseudomonas syringae pathovars and related pathogens has progressed rapidly, opening up many new avenues. The application of molecular genetics has provided new insights into determinants of pathogenicity and virulence. Progress has also been made in elucidating the chemical structures and modes of action of phytotoxins from Pseudomonas syringae; by establishing novel strategies for disease control; in biotechnological applications; by studying the resistant reaction of the plant with a combined biochemical and genetic approach; and in the development of new detection and identification methodologies as tools in epidemiological studies. With such rapid advances it becomes more and more difficult to keep abreast of the developments and concepts within disciplines, all involving research on pathovars of P. syringae. In an attempt to provide a balanced overview, recent developments in these rapidly expanding fields have been critically reviewed at the beginning of each chapter by internationally renowned experts. Our comprehensive coverage has been made possible because all the contributors to this volume presented their latest findings at the `5th International Conference on Pseudomonas syringae Pathovars and Related Pathogens' in Berlin, September 3-8, 1995. In this way, it was possible to bring together contributions from a wide range of fields including phytopathology, genetics, bacteriology, plant breeding, plant protection, and taxonomy. This book is not intended simply as a record of the proceedings of the Berlin Conference, but as an extension of recent findings and hypotheses put forward at the meeting. All papers published in this volume have been reviewed by the Editors.
Download or read book The Hypersensitive Reaction in Plants to Pathogens written by Robert N. Goodman and published by American Phytopathological Society. This book was released on 1994 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nikolai Gogol’s short story is a sublime work of tragi-comedy. In it, he brilliantly ridicules the Ukrainian passion for litigation and reveals life as something really rather absurd. Ivan Ivanovich and Ivan Nikiforovich are the greatest of friends—until the day they begin a foolish quarrel that culminates in that very worst of insults: “And you, Ivan Ivanovich, are a goose.” From that moment on, not another word is spoken between them as they choose instead to fight out their differences in the courts. But it seems theirs is a lawsuit that is set to run for years and years.
Download or read book Effectors in Plant Microbe Interactions written by Francis Martin and published by John Wiley & Sons. This book was released on 2012-01-03 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plants and microbes interact in a complex relationship that can have both harmful and beneficial impacts on both plant and microbial communities. Effectors, secreted microbial molecules that alter plant processes and facilitate colonization, are central to understanding the complicated interplay between plants and microbes. Effectors in Plant-Microbe Interactions unlocks the molecular basis of this important class of microbial molecules and describes their diverse and complex interactions with host plants. Effectors in Plant Microbe Interactions is divided into five sections that take stock of the current knowledge on effectors of plant-associated organisms. Coverage ranges from the impact of bacterial, fungal and oomycete effectors on plant immunity and high-throughput genomic analysis of effectors to the function and trafficking of these microbial molecules. The final section looks at effectors secreted by other eukaryotic microbes that are the focus of current and future research efforts. Written by leading international experts in plant-microbe interactions, Effectors in Plant Microbe Interactions, will be an essential volume for plant biologists, microbiologists, pathologists, and geneticists.
Download or read book The HRPL Regulon of the Plant Pathogenic Bacterium Pseudomonas Syringae written by Monica Vencato and published by . This book was released on 2006 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pseudomonas syringae and related pathogens written by Nicola Sante Iacobellis and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 673 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume mainly reports on new and recent advancements on different aspects of Pseudomonas syringae, a plant pathogenic bacterial species that include a high number of pathogens of important crops, which is an interesting model organism in plant pathology. In addition some related fluorescent Pseudomonas spp., responsible of new and emerging diseases, as well as some pathogens previously included in the above genus and now classified in the genera Ralstonia, Acidovorax are also considered. The tremendous recent advancements on: the ecology and epidemiology and, in particular, the adaptation of P. syringae to stresses and adverse environmental conditions; the function and regulation of genes involved in the production of phytotoxins and on their mechanism of action in the interaction with the host cells; the structure, function and regulation of type three secretion system (TTSS) and the transport of the effectors proteins in the host cells; the possibility to control diseases through the induction of the systemic acquired resistance (SAR); the development of molecular techniques for the highly specific and sensible identification and detection of pathogens; the determination of the causal agents of new and emerging diseases as well the classification of the different pathovars of P. syringae; are reported in 76 chapters cured by leading scientist in the respective fields.
Download or read book Type III Virulence Effectors of Pseudomonas Syringae Pv Tomato Strain DC3000 written by Sruti Bandyopadhyay and published by . This book was released on 2003 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sustainable Approaches to Controlling Plant Pathogenic Bacteria written by V. Rajesh Kannan and published by CRC Press. This book was released on 2015-09-08 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plant diseases and changes in existing pathogens remain a constant threat to our forests, food, and fiber crops as well as landscape plants. However, many economically important pathosystems are largely unexplored and biologically relevant life stages of familiar systems remain poorly understood. In a multifaceted approach to plant pathogenic behavioral control, Sustainable Approaches to Controlling Plant Pathogenic Bacteria discusses the impact of plant pathogenic bacterial pathogenesis on scientific and economic levels. It introduces mechanisms, measuring tools, and controlling strategies you can use to meet the challenge of developing new and innovative ways to control plant diseases. The book covers many aspects of the activities of pathogenic bacteria that interact with plants. With chapters contributed by experts, the book focuses on: Pathogenesis Epidemiology Forecasting systems Control measures including diagnosis, quarantine, and eradication Adoption of agro-traditional practices Tools for the control of antibacterial polypeptides Nutrient supplements Metabolic substances from other organisms Mechanisms of siderophores Host resistances Quorum sensing and quenching Seed and foliar applications Impact of plant pathogens on scientific and economic levels The editors’ approach provides a broad perspective, including modern trends in ecology that consider plant pathogenic bacterial control from all angles. The discussions and reviews in the book cover a wide range of aspects of plant pathogenic bacterial pathogenicity, epidemiology, and impact on the food chain as well as strategies for control, which will help you develop sustainable methods for controlling plant diseases.
Download or read book An In depth Analysis of Iron and Pathogenicity Regulatory Pathways in Pseudomonas Syringae Pv Syringae B728a written by Jessica Williams Greenwald and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Pseudomonas syringae pv. syringae strain B728a (P.s.s. B728a) is an economically significant plant pathogen that is capable of successful epiphytic colonization of leaf surfaces. Although the virulence factors associated with this pathogen's ability to cause disease have been well studied, the transition from epiphyte to pathogen is not well understood. The research described in this dissertation utilizes high throughput sequencing transcriptome analyses to define an iron regulatory network that is predicted to be utilized during the epiphytic portion of the P.s.s. B728a lifecycle. This dissertation also describes a collaborative microarray analysis that analyzes the P.s.s. B728a transcriptome at a global level. An iron associated sigma factor, AcsS, encoded within a peptide synthesis rich region of the P.s.s. B728a genome is shown to regulate the citrate siderophore achromobactin. RNA-seq transcriptome analysis reveals that this sigma factor regulates expression of genes predicted to be involved in functions that are important during the epiphytic stage of P.s.s. B728a, including genes involved in iron response, secretion, extracellular polysaccharide production, and cell motility. As part of a collaboration, the transcriptomes of the P.s.s. B728a genome and nine deletion mutants in regulatory genes were analyzed by microarray analayses using seven treatment conditions, including epiphytic and in planta conditions. As part of these microarray analyses, results are described for the global regulator, GacS, and a downstream transcription factor, SalA. This study confirms the role of GacS and SalA in the regulation of major virulence components of P.s.s. B728a such as phytotoxin production and Type III secretion. This study also elucidates a role for GacS and SalA regulation of genes important for epiphytic survival and function, including the Type VI secretion system, iron acquisition, and EPS production.
Download or read book Regulation of Bacterial Virulence written by Michael L. Vasil and published by American Society for Microbiology Press. This book was released on 2012-12-05 with total page 1189 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive compendium of scholarly contributions relating to bacterial virulence gene regulation. • Provides insights into global control and the switch between distinct infectious states (e.g., acute vs. chronic). • Considers key issues about the mechanisms of gene regulation relating to: surface factors, exported toxins and export mechanisms. • Reflects on how the regulation of intracellular lifestyles and the response to stress can ultimately have an impact on the outcome of an infection. • Highlights and examines some emerging regulatory mechanisms of special significance. • Serves as an ideal compendium of valuable topics for students, researchers and faculty with interests in how the mechanisms of gene regulation ultimately affect the outcome of an array of bacterial infectious diseases.
Download or read book Investigation of the Interconnected Roles of CmaL and HopAA1 1 In The Virulence Of Pseudomonas Syringae Pv Tomato DC3000 In Nicotiana Benthamiana written by Jay N. Worley and published by . This book was released on 2013 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pseudomonas syringae pv. tomato DC3000 (DC3000) is a model plant pathogenic bacterium that infects tomato and Arabidopsis thaliana. It requires the phytotoxin coronatine and the delivery of type III effector proteins (T3Es) into the host cell cytoplasm for defense suppression and virulence. CmaL is a small protein found to be necessary for coronatine production. Coronatine is a potent molecular mimic of jasmonoyl-isoleucine, a plant hormone conjugate involved in regulating plant defenses. Coronatine is constructed of two amide bond-linked moieties, coronafacic acid and coronamic acid. CmaL was shown to be required for the production of L-allo-isoleucine, a precursor for coronamic acid biosynthesis. DC3000 mutants lacking both cmaL and the T3E gene hopAA1-1 are reduced in speck formation in tomato. hopAA1-1 is member of the conserved effector locus, a group of effector genes located adjacent to the genes encoding the type three secretion apparatus that are widespread among P. syringae strains. HopAA1-1 is toxic to both plants and yeast upon expression within them. To gain insight into the basis for its toxicity in eukaryotic cells, the subcellular localization of HopAA1-1 was investigated. HopAA1-1 was found to colocalize with plant peroxisomes. Truncated derivatives of HopAA1-1 that are not cytotoxic and cannot promote symptom formation do not localize with peroxisomes. Additionally, other truncated derivatives of HopAA1-1 colocalize with the endoplasmic reticulum in addition to peroxisomes, suggesting that HopAA1 -1 interacts with the endomembrane system. A DC3000 mutant with 28 T3E genes deleted (DC3000D28E) is a recently developed tool for investigating effector functions. DC3000D28E derivatives with small sets of effector genes progressively restored show increasing virulence wh en inoculated by infiltration with a blunt syringe into the model plant Nicotiana benthamiana. Because of its location in a cluster of effector genes, cmaL was inadvertently deleted in the construction of DC3000D28E. The importance of coronatine and its partial redundancy with HopAA1-1 in promoting an early stage of pathogenesis was revealed by restoring cmaL and hopAA1-1 to selected DC3000D28E derivatives and assaying the strains by dip inoculation of N. benthamiana leaves, which requires bacteria to follow a natural infection route through stomata.
Download or read book Pseudomonas syringae Pathovars and Related Pathogens Identification Epidemiology and Genomics written by M’Barek Fatmi and published by Springer Science & Business Media. This book was released on 2008-06-03 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on recent advances on: (1) new methods and approaches for specific and sensitive detection and identification of Pseudomonas syringae and Ralstonia solanacearum; (2) ecology and epidemiology bases of Pseudomonas syringae that enable the development of management strategies; (3) pathogenesis and determinant of pathogenicity, and in particular, mechanisms involved in virulence and virulence gene expression; (4) evolution and diversity of the pseudomonads through multilocus sequence typing (MLST) analysis; (5) determination of pathogens associated with new and emerging diseases; (6) effect of global warming on increase and emergence of new bacterial diseases."
Download or read book Characterization Function and Regulation of Avirulence Genes from Pseudomonas Syringae Pv Tomato written by Jennifer Mae Lorang and published by . This book was released on 1993 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book This is 4 H written by and published by . This book was released on 1967 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
