scholarly journals Genome-Wide Gene Expression Analysis of Pseudomonas syringae pv. tomato DC3000 Reveals Overlapping and Distinct Pathways Regulated by hrpL and hrpRS

2006 ◽  
Vol 19 (9) ◽  
pp. 976-987 ◽  
Author(s):  
Lefu Lan ◽  
Xin Deng ◽  
Jianmin Zhou ◽  
Xiaoyan Tang
Keyword(s):  
Pseudomonas Syringae ◽  
Housekeeping Genes ◽  
The Novel ◽  
Tomato Dc3000 ◽  
Regulatory Pathways ◽  
Genome Wide ◽  
Genes Encoding ◽  
Substrate Proteins ◽  
Genome Wide Gene Expression ◽  
Insight Into

Pseudomonas syringae pv. tomato DC3000 is a model pathogen infecting tomato and Arabidopsis plants. Genes encoding the type III secretion system and substrate proteins (collectively called TTSS genes) of this bacterium are induced in plants and in minimal medium (MM). The induction of TTSS genes is mediated by HrpL, an alternative sigma factor recognizing the hrp box in the promoter of TTSS genes. The transcription of hrpL is activated by HrpR and HrpS, two homologous DNA-binding proteins encoded by the hrpRS operon. Microarray analysis was conducted to evaluate the DC3000 genes regulated by hrpL and hrpRS in MM. The analysis identified a number of novel hrpL-activated genes with a putative TTSS-independent function. Genes regulated by hrpL were mostly regulated by hrpRS in the same manner, but a large number of genes regulated by hrpRS were hrpL-independent, indicating that hrpL represents one branch of the regulatory pathways downstream of hrpRS. The induction of the TTSS genes was associated with downregulation of the housekeeping genes, indicating that the activation of the TTSS has a cost on the basic cellular activities. The novel genes and pathways identified by the microarray provide new insight into the bacterial functions coordinating with the TTSS.

scholarly journals Characterization of Regulatory Pathways in Xylella fastidiosa: Genes and Phenotypes Controlled by gacA

2009 ◽  
Vol 75 (8) ◽  
pp. 2275-2283 ◽  
Author(s):  
Xiang Yang Shi ◽  
C. Korsi Dumenyo ◽  
Rufina Hernandez-Martinez ◽  
Hamid Azad ◽  
Donald A. Cooksey
Keyword(s):  
Pseudomonas Syringae ◽  
Biofilm Formation ◽  
Xylella Fastidiosa ◽  
Cell Aggregation ◽  
Toxin Gene ◽  
Tomato Dc3000 ◽  
Disease Symptoms ◽  
Regulatory Pathways ◽  
Physiological Processes

ABSTRACT The xylem-limited, insect-transmitted bacterium Xylella fastidiosa causes Pierce's disease in grapes through cell aggregation and vascular clogging. GacA controls various physiological processes and pathogenicity factors in many gram-negative bacteria, including biofilm formation in Pseudomonas syringae pv. tomato DC3000. Cloned gacA of X. fastidiosa was found to restore the hypersensitive response and pathogenicity in gacA mutants of P. syringae pv. tomato DC3000 and Erwinia amylovora. A gacA mutant of X. fastidiosa (DAC1984) had significantly reduced abilities to adhere to a glass surface, form biofilm, and incite disease symptoms on grapevines, compared with the parent (A05). cDNA microarray analysis identified 7 genes that were positively regulated by GacA, including xadA and hsf, predicted to encode outer membrane adhesion proteins, and 20 negatively regulated genes, including gumC and an antibacterial polypeptide toxin gene, cvaC. These results suggest that GacA of X. fastidiosa regulates many factors, which contribute to attachment and biofilm formation, as well as some physiological processes that may enhance the adaptation and tolerance of X. fastidiosa to environmental stresses and the competition within the host xylem.

scholarly journals CorR Regulates Multiple Components of Virulence in Pseudomonas syringae pv. tomato DC3000

2006 ◽  
Vol 19 (7) ◽  
pp. 768-779 ◽  
Author(s):  
Aswathy Sreedharan ◽  
Alejandro Penaloza-Vazquez ◽  
Barbara N. Kunkel ◽  
Carol L. Bender
Keyword(s):  
Pseudomonas Syringae ◽  
Biosynthetic Pathway ◽  
Response Regulator ◽  
Tomato Dc3000 ◽  
Tomato Plants ◽  
Coronafacic Acid ◽  
Multiple Components ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Polymerase Chain

The phytotoxin coronatine (COR) is produced by various pathovars of Pseudomonas syringae, including P. syringae pv. tomato DC3000, which is pathogenic on crucifers and tomato, and P. syringae pv. glycinea PG4180, a soybean pathogen. The COR molecule contains two distinct components, coronafacic acid (CFA) and coronamic acid (CMA), which are intermediates in the COR biosynthetic pathway. In P. syringae pv. tomato DC3000, it is not clear whether corR, which encodes a response regulator, positively regulates CFA and CMA synthesis as it does in P. syringae pv. glycinea PG4180. In this study, a corR mutant of P. syringae pv. tomato DC3000 was constructed and was shown to be defective in the production of COR, CFA, and CMA. Furthermore, disease severity was greatly reduced in tomato plants inoculated with the corR mutant compared with wild-type P. syringae pv. tomato DC3000. We also showed that a mutation in hrpL, which encodes an alternate RNA polymerase sigma factor (σL) required for the expression of genes encoding components of the type III secretion system, abrogated production of COR in P. syringae pv. tomato DC3000. The presence of a potential hrp box, the recognition site for σL, upstream of corR suggested that corR might be regulated by hrpL. This was confirmed in reverse-transcription polymerase chain reaction experiments showing that the upstream effector gene holPtoAA, which was associated with the hrp box, was cotranscribed with corR. Furthermore, studies also were conducted to investigate whether mutations in corR had effects on the expression of hrpL. The corR mutant of P. syringae pv. tomato DC3000 showed both a reduction and delay in the expression of hrpL and was impaired in its ability to elicit a hypersensitive response on Nicotiana benthamiana. A putative CorR-binding site was identified upstream of hrpL, and gel shift studies confirmed the binding of CorR to this region. These results indicate that corR directly impacts the expression of the hrp regulon in P. syringae.

scholarly journals Recombineering Using RecTE from Pseudomonas syringae

2010 ◽  
Vol 76 (15) ◽  
pp. 4960-4968 ◽  
Author(s):  
Bryan Swingle ◽  
Zhongmeng Bao ◽  
Eric Markel ◽  
Alan Chambers ◽  
Samuel Cartinhour
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Syringae ◽  
Recombination Frequency ◽  
Quantitative Assay ◽  
Tomato Dc3000 ◽  
Linear Dna ◽  
Dna Oligonucleotides ◽  
Double Stranded Dna ◽  
Genes Encoding ◽  
Genomic Recombination

ABSTRACT In this report, we describe the identification of functions that promote genomic recombination of linear DNA introduced into Pseudomonas cells by electroporation. The genes encoding these functions were identified in Pseudomonas syringae pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecET proteins encoded by the lambda and Rac bacteriophages of Escherichia coli. The ability of the pseudomonad-encoded proteins to promote recombination was tested in P. syringae pv. tomato DC3000 using a quantitative assay based on recombination frequency. The results show that the Pseudomonas RecT homolog is sufficient to promote recombination of single-stranded DNA oligonucleotides and that efficient recombination of double-stranded DNA requires the expression of both the RecT and RecE homologs. Additionally, we illustrate the utility of this recombineering system to make targeted gene disruptions in the P. syringae chromosome.

scholarly journals The Phytotoxin Coronatine Contributes to Pathogen Fitness and Is Required for Suppression of Salicylic Acid Accumulation in Tomato Inoculated with Pseudomonas syringae pv. tomato DC3000

2007 ◽  
Vol 20 (8) ◽  
pp. 955-965 ◽  
Author(s):  
Srinivasa Rao Uppalapati ◽  
Yasuhiro Ishiga ◽  
Tamding Wangdi ◽  
Barbara N. Kunkel ◽  
Ajith Anand ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Tomato Dc3000 ◽  
Defense Proteins ◽  
Tomato Plants ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Salicylic Acid Accumulation ◽  
Pathogen Fitness

The roles of the phytotoxin coronatine (COR) and salicylic acid (SA)-mediated defenses in the interaction of Pseudomonas syringae pv. tomato DC3000 and tomato (Solanum lycopersicum) were investigated. Unlike findings reported for Arabidopsis thaliana, DC3000 mutants impaired for production of COR or one of its components, coronafacic acid (CFA) or coronamic acid (CMA), induced distinctly different disease lesion phenotypes in tomato. Tomato plants inoculated with the CFA- CMA- mutant DB29 showed elevated transcript levels of SlICS, which encodes isochorismate synthase, an enzyme involved in SA biosynthesis in S. lycopersicum. Furthermore, expression of genes encoding SA-mediated defense proteins were elevated in DB29-inoculated plants compared with plants inoculated with DC3000, suggesting that COR suppresses SlICS-mediated SA responses. Sequence analysis of SlICS revealed that it encodes a protein that is 55 and 59.6% identical to the A. thaliana ICS-encoded proteins AtICS1 and AtICS2, respectively. Tomato plants silenced for SlICS were hypersusceptible to DC3000 and accumulated lower levels of SA after infection with DC3000 compared with inoculated wild-type tomato plants. Unlike what has been shown for A. thaliana, the COR- mutant DB29 was impaired for persistence in SlICS-silenced tomato plants; thus, COR has additional roles in virulence that are SA independent and important in the latter stages of disease development. In summary, the infection assays, metabolic profiling, and gene expression results described in this study indicate that the intact COR molecule is required for both suppression of SA-mediated defense responses and full disease symptom development in tomato.

scholarly journals Fitness costs and benefits of gene expression plasticity in rice under drought

2021 ◽  
Author(s):  
Simon C Groen ◽  
Elena Hamann ◽  
Irina Calic ◽  
Colleen Cochran ◽  
Rachel Konshok ◽  
...  
Keyword(s):  
Gene Expression ◽  
Environmental Variability ◽  
Housekeeping Genes ◽  
Costs And Benefits ◽  
Compensatory Evolution ◽  
Architectural Features ◽  
Genome Wide ◽  
A Genome ◽  
Gene Modules ◽  
Genome Wide Gene Expression

Genome-wide gene expression changes in response to environmental variability have been widely documented, but we lack detailed and comprehensive understanding of the interplay between this form of phenotypic plasticity and natural selection. Selection on expression plasticity may be limited by environment-specific costs, and plasticity may in turn affect selection on baseline expression levels. Here, we address this fundamental issue by measuring selection on drought-induced plasticity of leaf transcripts in field-grown rice populations. Selection disfavored switching off housekeeping genes under drought. This stress-induced dysregulation did not constrain selection on baseline transcript levels, suggesting compensatory evolution may be possible. Selection rarely acted strongly on individual transcripts but worked polygenically on gradual (continuous) plasticity of co-expressed gene modules regulating photosynthesis via known drought-responsive transcription factors. Finally, selection was tied to inefficient gene architectural features and metabolic costs of expression. Our study provides a genome-wide view of costs and benefits of gene expression plasticity.

scholarly journals Closing the Circle on the Discovery of Genes Encoding Hrp Regulon Members and Type III Secretion System Effectors in the Genomes of Three Model Pseudomonas syringae Strains

2006 ◽  
Vol 19 (11) ◽  
pp. 1151-1158 ◽  
Author(s):  
Magdalen Lindeberg ◽  
Samuel Cartinhour ◽  
Christopher R. Myers ◽  
Lisa M. Schechter ◽  
David J. Schneider ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Active Member ◽  
Tomato Dc3000 ◽  
Type Iii ◽  
Effector Genes ◽  
Genes Encoding

Pseudomonas syringae strains translocate large and distinct collections of effector proteins into plant cells via the type III secretion system (T3SS). Mutations in T3SS-encoding hrp genes are unable to elicit the hypersensitive response or pathogenesis in nonhost and host plants, respectively. Mutations in individual effectors lack strong phenotypes, which has impeded their discovery. P. syringae effectors are designated Hop (Hrp outer protein) or Avr (avirulence) proteins. Some Hop proteins are considered to be extracellular T3SS helpers acting at the plant-bacterium interface. Identification of complete sets of effectors and related proteins has been enabled by the application of bioinformatic and high-throughput experimental techniques to the complete genome sequences of three model strains: P. syringae pv. tomato DC3000, P. syringae pv. phaseolicola 1448A, and P. syringae pv. syringae B728a. Several recent papers, including three in this issue of Molecular Plant-Microbe Interactions, address the effector inventories of these strains. These studies establish that active effector genes in P. syringae are expressed by the HrpL alternative sigma factor and can be predicted on the basis of cis Hrp promoter sequences and N-terminal amino-acid patterns. Among the three strains analyzed, P. syringae pv. tomato DC3000 has the largest effector inventory and P. syringae pv. syringae B728a has the smallest. Each strain has several effector genes that appear inactive. Only five of the 46 effector families that are represented in these three strains have an active member in all of the strains. Web-based community resources for managing and sharing growing information on these complex effector arsenals should help future efforts to understand how effectors promote P. syringae virulence.

scholarly journals Transcriptomics supports that pleuropodia of insect embryos function in degradation of the serosal cuticle to enable hatching

2019 ◽  
Author(s):  
Barbora Konopová ◽  
Elisa Buchberger ◽  
Alastair Crisp
Keyword(s):  
Gene Expression ◽  
Schistocerca Gregaria ◽  
Immune Defense ◽  
Hatching Enzyme ◽  
Transmission Electron ◽  
Genome Wide ◽  
Genes Encoding ◽  
Insect Embryos ◽  
Epithelial Immunity ◽  
Genome Wide Gene Expression

ABSTRACTPleuropodia are limb-derived vesicular organs that transiently appear on the first abdominal segment of embryos from the majority of insect “orders”. They are missing in the model Drosophila and little is known about them. Experiments carried out on orthopteran insects eighty years ago indicated that the pleuropodia secrete a “hatching enzyme” that at the end of embryogenesis digests the serosal cuticle to enable the larva to hatch. This hypothesis contradicts the view that insect cuticle is digested by enzymes produced by the tissue that deposited it. We studied the development of the pleuropodia in embryos of the locust Schistocerca gregaria (Orthoptera) using transmission electron microscopy. RNA-seq was applied to generate a comprehensive embryonic reference transcriptome that was used to study genome-wide gene expression of ten stages of pleuropodia development. We show that the mature and secretion releasing pleuropodia are primarily enriched in transcripts associated with transport functions. They express genes encoding enzymes capable of digesting cuticular protein and chitin. These include the potent cuticulo-lytic Chitinase 5, whose transcript rises just before hatching. The pleuropodia are also enriched in transcripts for immunity-related enzymes, including the Toll signaling pathway, melanization cascade and lysozymes. These data provide transcriptomic evidence that the pleuropodia of orthopterans produce the “hatching enzyme”, whose important component is the Chitinase 5. They also indicate that the organs facilitate epithelial immunity and may function in embryonic immune defense. Based on their gene expression the pleuropodia appear to be an essential part of insect physiology.

The Monk

2016 ◽  
Author(s):  
Matthew Lewis
Keyword(s):  
French Revolution ◽  
English Literature ◽  
Young Girl ◽  
The Novel ◽  
Reading Public ◽  
Ghost Stories ◽  
Gothic Fiction ◽  
Black Magic ◽  
Insight Into ◽  
Profound Insight

‘He was deaf to the murmurs of conscience, and resolved to satisfy his desires at any price.’ The Monk (1796) is a sensational story of temptation and depravity, a masterpiece of Gothic fiction and the first horror novel in English literature. The respected monk Ambrosio, the Abbot of a Capuchin monastery in Madrid, is overwhelmed with desire for a young girl; once having abandoned his monastic vows he begins a terrible descent into immorality and violence. His appalling fall from grace embraces blasphemy, black magic, torture, rape, and murder, and places his very soul in jeopardy. Lewis’s extraordinary tale drew on folklore, legendary ghost stories, and contemporary dread inspired by the terrors of the French Revolution. Its excesses shocked the reading public and it was condemned as obscene. The novel continues to beguile and shock readers today with its gruesome catalogue of iniquities, while at the same time giving a profound insight into the deep anxieties experienced by British citizens during one of the most turbulent periods in the nation’s history.

Sign in / Sign up

Export Citation Format

Share Document