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 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 Photo sensing and quorum sensing are integrated to control bacterial group behaviors

2019 ◽  
Author(s):  
Sampriti Mukherjee ◽  
Matthew Jemielita ◽  
Vasiliki Stergioula ◽  
Mikhail Tikhonov ◽  
Bonnie L. Bassler
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Response Regulator ◽  
Sensory Information ◽  
Virulence Gene ◽  
Component System ◽  
Virulence Gene Expression ◽  
Bacterial Phyla ◽  
Expression Of Genes ◽  
Genes Encoding

ABSTRACTPseudomonas aeruginosa transitions between the free-swimming state and the sessile biofilm mode during its pathogenic lifestyle. We show that quorum sensing represses P. aeruginosa biofilm formation and virulence by activating expression of genes encoding the KinB-AlgB two-component system. Phospho-AlgB represses biofilm and virulence genes, while KinB dephosphorylates, and thereby, inactivates AlgB. We discover that the photoreceptor BphP is the kinase that, in response to light, phosphorylates and activates AlgB. Indeed, exposing P. aeruginosa to light represses biofilm formation and virulence gene expression. To our knowledge, P. aeruginosa was not previously known to detect light. The KinB-AlgB-BphP module is present in all Pseudomonads, and we demonstrate that AlgB is the cognate response regulator for BphP in diverse bacterial phyla. We propose that KinB-AlgB-BphP constitutes a “three-component” system and AlgB is the node at which varied sensory information is integrated. This study sets the stage for light-mediated control of P. aeruginosa infectivity.

scholarly journals Expression of genes encoding IGFBPs, SNARK, CD36, and PECAM1 in the liver of mice treated with chromium disilicide and titanium nitride nanoparticles

2017 ◽  
Vol 51 (2) ◽  
pp. 84-95
Author(s):  
Dmytro O. Minchenko ◽  
D. O. Tsymbal ◽  
O. P. Yavorovsky ◽  
N. V. Solokha ◽  
O. H. Minchenko
Keyword(s):  
Titanium Nitride ◽  
Mouse Liver ◽  
Quantitative Polymerase Chain Reaction ◽  
Down Regulation ◽  
Expression Of Genes ◽  
Genes Expression ◽  
Genes Encoding ◽  
Polymerase Chain ◽  
Working Day ◽  
20 Nm

AbstractObjective. The aim of the present study was to examine the effect of chromium disilicide and titanium nitride nanoparticles on the expression level of genes encoding important regulatory factors (IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK/NUAK2, CD36, and PECAM1/CD31) in mouse liver for evaluation of possible toxic effects of these nanoparticles.Methods. Male mice received 20 mg chromium disilicide nanoparticles (45 nm) and titanium nitride nanoparticles (20 nm) with food every working day for 2 months. The expression of IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK, CD36, and PECAM1 genes in mouse liver was studied by quantitative polymerase chain reaction.Results. Treatment of mice with chromium disilicide nanoparticles led to down-regulation of the expression of IGFBP2, IGFBP5, PECAM1, and SNARK genes in the liver in comparison with control mice, with more prominent changes for SNARK gene. At the same time, the expression of IGFBP3 and CD36 genes was increased in mouse liver upon treatment with chromium disilicide nanoparticles. We have also shown that treatment with titanium nitride nanoparticles resulted in down-regulation of the expression of IGFBP2 and SNARK genes in the liver with more prominent changes for SNARK gene. At the same time, the expression of IGFBP3, IGFBP4, and CD36 genes was increased in the liver of mice treated with titanium nitride nanoparticles. Furthermore, the effect of chromium disilicide nanoparticles on IGFBP2 and CD36 genes expression was significantly stronger as compared to titanium nitride nanoparticles.Conclusions. The results of this study demonstrate that chromium disilicide and titanium nitride nanoparticles have variable effects on the expression of IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK, CD36, and PECAM1 genes in mouse liver, which may reflect the genotoxic activities of the studied nanoparticles.

scholarly journals Chitosan Oligosaccharide Induces Resistance to Pseudomonas syringae pv. tomato DC3000 in Arabidopsis thaliana by Activating Both Salicylic Acid– and Jasmonic Acid–Mediated Pathways

2018 ◽  
Vol 31 (12) ◽  
pp. 1271-1279 ◽  
Author(s):  
Xiaochen Jia ◽  
Haihong Zeng ◽  
Wenxia Wang ◽  
Fuyun Zhang ◽  
Heng Yin
Keyword(s):  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Induced Resistance ◽  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
Chitosan Oligosaccharide ◽  
Induction Effect ◽  
Tomato Dc3000 ◽  
Expression Of Genes ◽  
Underlying Mechanisms

Chitosan oligosaccharide (COS) is an effective plant immunity elicitor; however, its induction mechanism in plants is complex and needs further investigation. In this study, the Arabidopsis–Pseudomonas syringae pv. tomato DC3000 (hereafter called DC3000) interaction was used to investigate the induction effect and the underlying mechanisms of COS. COS is effective in inducing resistance to DC3000 in Arabidopsis, and our results demonstrate that treatment with COS 3 days before DC3000 inoculation provided the most effective resistance. Disease severity in jar1 (jasmonic acid [JA]-deficient mutant), NahG, and sid2 (salicylic acid [SA]-deficient mutants) suggest both the SA and JA pathways are required for the Arabidopsis response to DC3000. COS pretreatment induced resistance in wild type (WT), jar1, and also, although to a lesser degree, in NahG and sid2 plants, implying that the SA and JA pathways play redundant roles in COS-induced resistance to DC3000. In COS-pretreated plants, expression of genes related to the SA pathway (PR1, PR2, and PR5) and SA content increased in both WT and jar1. Moreover, expression of genes related to the JA pathway (PDF1.2 and VSP2) and JA content both increased in WT and NahG. In conclusion, COS induces resistance to DC3000 in Arabidopsis by activating both SA- and JA-mediated pathways, although SA and JA pathways play redundant roles in this COS-induced resistance.

scholarly journals Pseudomonas syringae Two-Component Response Regulator RhpR Regulates Promoters Carrying an Inverted Repeat Element

2010 ◽  
Vol 23 (7) ◽  
pp. 927-939 ◽  
Author(s):  
Xin Deng ◽  
Lefu Lan ◽  
Yanmei Xiao ◽  
Megan Kennelly ◽  
Jian-Min Zhou ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Inverted Repeat ◽  
Response Regulator ◽  
Effector Proteins ◽  
Dependent Manner ◽  
Type Iii ◽  
Regulatory Cascade ◽  
Two Component ◽  
Genes Encoding ◽  
Element Activity

The two-component system RhpRS was identified in Pseudomonas syringae as a regulator of the genes encoding the type III secretion system and type III effector proteins (together called the T3 genes). In the absence of the sensor kinase RhpS, the response regulator RhpR represses the induction of the T3 gene regulatory cascade consisting of hrpRS, hrpL, and the T3 genes in a phosphorylation-dependent manner. The repressor activity of RhpR is inhibited by RhpS, which presumably acts as a phosphatase under the T3 gene inducing conditions. Here, we show that RhpR binds and induces its own promoter in a phosphorylation-dependent manner. Deletion and mutagenesis analyses revealed an inverted repeat (IR) element, GTATC-N6-GATAC, in the rhpR promoter that confers the RhpR-dependent induction. Computational search of the P. syringae genomes for the putative IR elements and Northern blot analysis of the genes with a putative IR element in the promoter region uncovered five genes that were upregulated and two genes that were downregulated in an RhpR-dependent manner. Two genes that were strongly induced by RhpR were assayed for the IR element activity in gene regulation and, in both cases, the IR element mediated the RhpR-dependent gene induction. Chromatin immunoprecipitation assays indicated that RhpR binds the promoters containing a putative IR element but not the hrpR and hrpL promoters that do not have an IR element, suggesting that RhpR indirectly regulates the transcriptional cascade of hrpRS, hrpL, and the T3 genes.

scholarly journals Differential Expression of Genes Encoding Arabidopsis Phospholipases After Challenge with Virulent or Avirulent Pseudomonas Isolates

2002 ◽  
Vol 15 (8) ◽  
pp. 808-816 ◽  
Author(s):  
Marta de Torres Zabela ◽  
Isabelle Fernandez-Delmond ◽  
Totte Niittyla ◽  
Pedro Sanchez ◽  
Murray Grant
Keyword(s):  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Gene Interactions ◽  
Gene Encoding ◽  
Cellular Processes ◽  
Expression Of Genes ◽  
Pathogen Challenge ◽  
Genes Encoding ◽  
Plant Pathogen Interactions ◽  
Gene For Gene

Phospholipase D (PLD; EC 3.1.4.4) has been linked to a number of cellular processes, including Tran membrane signaling and membrane degradation. Four PLD genes (α, β, γ1, and γ2) have been cloned from Arabidopsis thalami. They encode isoforms with distinct regulatory and catalytic properties but little is known about their physiological roles. Using cDNA amplified fragment length polymorphism display and RNA blot analysis, we identified Arabidopsis PLDγ1 and a gene encoding a lysophospholipase (EC 3.1.1.5), lysoPL1, to be differentially expressed during host response to virulent and avirulent pathogen challenge. Examination of the expression pattern of phospholipase genes induced in response to pathogen challenge was undertaken using the lysoPL1 and gene-specific probes corresponding to the PLD isoforms α, β, and γ1. Each mRNA class exhibited different temporal patterns of expression after infiltration of leaves with Pseudomonas syringae pv. tomato with or without avrRpm1. PLDα was rapidly induced and remained constitutively elevated regardless of treatment. PLDβ was transiently induced upon pathogen challenge. However, mRNA for the lysoPL1 and PLDγ1 genes showed enhanced and sustained elevation during an incompatible interaction, in both ndr1 and overexpressing NahG genetic backgrounds. Further evidence for differential engagement of these PLD mRNA during defense responses, other than gene-for-gene interactions, was demonstrated by their response to salicylic acid treatment or wounding. Our results indicate that genes encoding lysoPL1, PLDγ1, and PLDβ are induced during early responses to pathogen challenge and, additionally, PLDγ1 and lysoPL1 are specifically upregulated during gene-for-gene interactions, leading to the hypersensitive response. We discuss the possible role of these genes in plant-pathogen interactions.

scholarly journals Pseudomonas syringae pv. tomato DC3000 CmaL (PSPTO4723), a DUF1330 Family Member, Is Needed To Produce l-allo-Isoleucine, a Precursor for the Phytotoxin Coronatine

2012 ◽  
Vol 195 (2) ◽  
pp. 287-296 ◽  
Author(s):  
Jay N. Worley ◽  
Alistair B. Russell ◽  
Aaron G. Wexler ◽  
Philip A. Bronstein ◽  
Brian H. Kvitko ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Genomic Region ◽  
Tomato Dc3000 ◽  
Content Type ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Coronafacic Acid ◽  
Feeding Experiments ◽  
Leaf Chlorosis

ABSTRACTPseudomonas syringaepv. tomato DC3000 produces the phytotoxin coronatine, a major determinant of the leaf chlorosis associated with DC3000 pathogenesis. The DC3000 PSPTO4723 (cmaL) gene is located in a genomic region encoding type III effectors; however, it promotes chlorosis in the model plantNicotiana benthamianain a manner independent of type III secretion. Coronatine is produced by the ligation of two moieties, coronafacic acid (CFA) and coronamic acid (CMA), which are produced by biosynthetic pathways encoded in separate operons. Cross-feeding experiments, performed inN. benthamianawithcfa,cma, andcmaLmutants, implicate CmaL in CMA production. Furthermore, analysis of bacterial supernatants under coronatine-inducing conditions revealed that mutants lacking either thecmaoperon orcmaLaccumulate CFA rather than coronatine, supporting a role for CmaL in the regulation or biosynthesis of CMA. CmaL does not appear to regulate CMA production, since the expression of proteins with known roles in CMA production is unaltered incmaLmutants. Rather, CmaL is needed for the first step in CMA synthesis, as evidenced by the fact that wild-type levels of coronatine production are restored to a ΔcmaLmutant when it is supplemented with 50 μg/mll-allo-isoleucine, the starting unit for CMA production.cmaLis found in all other sequencedP. syringaestrains with coronatine biosynthesis genes. This characterization of CmaL identifies a critical missing factor in coronatine production and provides a foundation for further investigation of a member of the widespread DUF1330 protein family.

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 Identification and Characterization of a Well-Defined Series of Coronatine Biosynthetic Mutants of Pseudomonas syringae pv. tomato DC3000

2004 ◽  
Vol 17 (2) ◽  
pp. 162-174 ◽  
Author(s):  
David M. Brooks ◽  
Gustavo Hernández-Guzmán ◽  
Andrew P. Kloek ◽  
Francisco Alarcón-Chaidez ◽  
Aswathy Sreedharan ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
High Performance ◽  
Tomato Dc3000 ◽  
Disease Symptoms ◽  
Coronafacic Acid ◽  
Tn5 Mutants ◽  
Cor Genes ◽  
Identification And Characterization

To identify Pseudomonas syringae pv. tomato genes involved in pathogenesis, we carried out a screen for Tn5 mutants of P. syringae pv. tomato DC3000 with reduced virulence on Arabidopsis thaliana. Several mutants defining both known and novel virulence loci were identified. Six mutants contained insertions in biosynthetic genes for the phytotoxin coronatine (COR). The P. syringae pv. tomato DC3000 COR genes are chromosomally encoded and are arranged in two separate clusters, which encode enzymes responsible for the synthesis of coronafacic acid (CFA) or coronamic acid (CMA), the two defined intermediates in COR biosynthesis. High-performance liquid chromatography fractionation and exogenous feeding studies confirmed that Tn5 insertions in the cfa and cma genes disrupt CFA and CMA biosynthesis, respectively. All six COR biosynthetic mutants were significantly impaired in their ability to multiply to high levels and to elicit disease symptoms on A. thaliana plants. To assess the relative contributions of CFA, CMA, and COR in virulence, we constructed and characterized cfa6 cmaA double mutant strains. These exhibited virulence phenotypes on A. thalliana identical to those observed for the cmaA or cfa6 single mutants, suggesting that reduced virulence of these mutants on A. thaliana is caused by the absence of the intact COR toxin. This is the first study to use biochemically and genetically defined COR mutants to address the role of COR in pathogenesis.

scholarly journals Comparative Metabolomic Analysis Reveals Distinct Flavonoid Biosynthesis Regulation for Leaf Color Development of Cymbidium sinense ‘Red Sun’

2020 ◽  
Vol 21 (5) ◽  
pp. 1869 ◽  
Author(s):  
Jie Gao ◽  
Rui Ren ◽  
Yonglu Wei ◽  
Jianpeng Jin ◽  
Sagheer Ahmad ◽  
...  
Keyword(s):  
Enzyme Activities ◽  
Biosynthetic Pathway ◽  
Color Change ◽  
Leaf Color ◽  
Anthocyanin Biosynthetic Pathway ◽  
Expression Of Genes ◽  
Genes Expression ◽  
Genes Encoding ◽  
Changing Patterns ◽  
Cymbidium Sinense

The colorful leaf is an important ornamental character of Cymbidium sinense (C. sinense), especially the red leaf, which has always been attracted by breeders and consumers. However, little is documented on the formation mechanism of the red leaf of C. sinense. In this study, the changing patterns of flavonoid-related metabolites, corresponding enzyme activities and genes expression in the leaves of C. sinense ‘Red Sun’ from red to yellow and finally to green was investigated. A total of 196 flavonoid-related metabolites including 11 anthocyanins metabolites were identified using UPLC-MS/MS-based approach. In the process of leaf color change, 42 metabolites were identified as having significantly different contents and the content of 28 differential metabolites turned to zero. In anthocyanin biosynthetic pathway, content of all 15 identified metabolites showed downregulation trend in the process of leaf color change. Among the 15 metabolites, the contents of Naringenin chalcone, Pelargonidin O-acetylhexoside and Anthocyanin 3-O-beta-d-glucoside decreased to zero in the green leaf stage. The changing pattern of enzyme activity of 10 enzymes involved in the anthocyanin biosynthetic pathway showed different trends from red leaves that have turned yellow and finally green, while the expression of genes encoding these enzymes was all down-regulated in the process of leaf color change. The results of this study revealed the types of flavonoid-related metabolites and the comprehensive analysis of metabolites content, enzyme activities and genes expression providing a new reference for breeders to improve the leaf color of C. sinense ‘Red Sun’.

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