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Illuminating the signalomics of microbial biofilm on plant surfaces. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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2
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Zhou Y, Bu Z, Qian J, Cheng Y, Qiao L, Yang S, Cheng S, Wang X, Ren L, Yang Y. Brucella melitensis UGPase inhibits the activation of NF-κB by modulating the ubiquitination of NEMO. BMC Vet Res 2021; 17:289. [PMID: 34461896 PMCID: PMC8404259 DOI: 10.1186/s12917-021-02993-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND UTP-glucose-1-phosphoryl transferase (UGPase) catalyzes the synthesis of UDP-glucose, which is essential for generating the glycogen needed for the synthesis of bacterial lipopolysaccharide (LPS) and capsular polysaccharide, which play important roles in bacterial virulence. However, the molecular function of UGPase in Brucella is still unknown. RESULTS In this study, the ubiquitination modification of host immune-related protein in cells infected with UGPase-deleted or wild-type Brucella was analyzed using ubiquitination proteomics technology. The ubiquitination modification level and type of NF-κB Essential Modulator (NEMO or Ikbkg), a molecule necessary for NF-κB signal activation, was evaluated using Coimmunoprecipitation, Western blot, and dual-Luciferase Assay. We found 80 ubiquitin proteins were upregulated and 203 ubiquitin proteins were downregulated in cells infected with B. melitensis 16 M compared with those of B. melitensis UGPase-deleted strain (16 M-UGPase-). Moreover, the ubiquitin-modified proteins were mostly enriched in the categories of regulation of kinase/NF-κB signaling and response to a bacterium, suggesting Brucella UGPase inhibits ubiquitin modification of related proteins in the host NF-κB signaling pathway. Further analysis showed that the ubiquitination levels of NEMO K63 (K63-Ub) and Met1 (Met1-Ub) were significantly increased in the 16 M-UGPase--infected cells compared with that of the 16 M-infected cells, further confirming that the ubiquitination levels of NF-κB signaling-related proteins were regulated by the bacterial UGPase. Besides, the expression level of IκBα was decreased, but the level of p-P65 was significantly increased in the 16 M-UGPase--infected cells compared with that of the 16 M- and mock-infected cells, demonstrating that B. melitensis UGPase can significantly inhibit the degradation of IκBα and the phosphorylation of p65, and thus suppressing the NF-κB pathway. CONCLUSIONS The results of this study showed that Brucella melitensis UGPase inhibits the activation of NF-κB by modulating the ubiquitination of NEMO, which will provide a new scientific basis for the study of immune mechanisms induced by Brucella.
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Affiliation(s)
- Yucheng Zhou
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, 130112, Changchun, China
| | - Zhaoyang Bu
- Military Veterinary Institute, Academy of Military Medical Sciences, 130112, Changchun, China
| | - Jing Qian
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, 210014, Nanjing, China
| | - Yuening Cheng
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, 130112, Changchun, China
| | - Lianjiang Qiao
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, 130112, Changchun, China
| | - Sen Yang
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, 130112, Changchun, China
| | - Shipeng Cheng
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, 130112, Changchun, China
| | - Xinglong Wang
- Military Veterinary Institute, Academy of Military Medical Sciences, 130112, Changchun, China
| | - Linzhu Ren
- College of Animal Sciences, Jilin University, 130062, Changchun, China.
| | - Yanling Yang
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, 130112, Changchun, China.
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Zhao X, Yang F, Wang Y, Zhang Y. hns mRNA downregulates the expression of galU and attenuates the motility of Salmonella enterica serovar Typhi. Int J Med Microbiol 2021; 311:151525. [PMID: 34340061 DOI: 10.1016/j.ijmm.2021.151525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 07/11/2021] [Accepted: 07/25/2021] [Indexed: 10/20/2022] Open
Abstract
Recently, multiple bifunctional RNAs have been discovered, which can both be translated into proteins and play regulatory roles. hns encodes the global gene silencing factor H-NS, which is widespread in Gram-negative bacteria. This study reported that hns mRNA of Salmonella enterica serovar Typhi (S. Typhi) was a bifunctional RNA that could act as an antisense RNA downregulating the expression of galU, the coding gene of uridine triphosphate-glucose-1-phosphate uridylyltransferase, and attenuating bacterial motility. galU, which is located at the opposite strand of hns, was identified to have a long 3'-untranslated region that overlapped with hns and could be processed to produce short RNA fragments. The overexpression of hns mRNA inhibited the expression of galU. The deletion of galU attenuated the motility of S. Typhi, while the complementation of galU nearly restored the phenotype. Overexpressing hns mRNA in the wild-type strain of S. Typhi inhibited the motility and the expression of flagellar genes, while overexpressing hns mRNA in the galU-deletion mutant did not influence bacterial motility. In conclusion, hns mRNA has been identified to be a new bifunctional RNA that attenuates the motility of S. Typhi by downregulating the expression of galU.
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Affiliation(s)
- Xin Zhao
- Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, 210006, China.
| | - Fanfan Yang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Yurou Wang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
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Bartnik P, Jafra S, Narajczyk M, Czaplewska P, Czajkowski R. Pectobacterium parmentieri SCC 3193 Mutants with Altered Synthesis of Cell Surface Polysaccharides Are Resistant to N4-Like Lytic Bacteriophage ϕA38 (vB_Ppp_A38) but Express Decreased Virulence in Potato ( Solanum tuberosum L.) Plants. Int J Mol Sci 2021; 22:7346. [PMID: 34298965 PMCID: PMC8304393 DOI: 10.3390/ijms22147346] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/02/2021] [Accepted: 07/06/2021] [Indexed: 01/15/2023] Open
Abstract
Pectobacterium parmentieri is a Gram-negative plant-pathogenic bacterium able to infect potato (Solanum tuberosum L.). Little is known about lytic bacteriophages infecting P. parmentieri and how phage-resistance influences the environmental fitness and virulence of this species. A lytic phage vB_Ppp_A38 (ϕA38) has been previously isolated and characterized as a potential biological control agent for the management of P. parmentieri. In this study, seven P. parmentieri SCC 3193 Tn5 mutants were identified that exhibited resistance to infection caused by vB_Ppp_A38 (ϕA38). The genes disrupted in these seven mutants encoded proteins involved in the assembly of O-antigen, sugar metabolism, and the production of bacterial capsule exopolysaccharides. The potential of A38-resistant P. parmentieri mutants for plant colonization and pathogenicity as well as other phenotypes expected to contribute to the ecological fitness of P. parmentieri, including growth rate, use of carbon and nitrogen sources, production of pectinolytic enzymes, proteases, cellulases, and siderophores, swimming and swarming motility, presence of capsule and flagella as well as the ability to form biofilm were assessed. Compared to the wild-type P. parmentieri strain, all phage-resistant mutants exhibited a reduced ability to colonize and to cause symptoms in growing potato (S. tuberosum L.) plants. The implications of bacteriophage resistance on the ecological fitness of P. parmentieri are discussed.
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Affiliation(s)
- Przemyslaw Bartnik
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, Antoniego Abrahama 58, 80-307 Gdansk, Poland;
| | - Sylwia Jafra
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, Antoniego Abrahama 58, 80-307 Gdansk, Poland;
| | - Magdalena Narajczyk
- Laboratory of Electron Microscopy, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Paulina Czaplewska
- Laboratory of Mass Spectrometry-Core Facility Laboratories, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, Antoniego Abrahama 58, 80-307 Gdansk, Poland;
| | - Robert Czajkowski
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, Antoniego Abrahama 58, 80-307 Gdansk, Poland;
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Genome-Wide Analyses of the Temperature-Responsive Genetic Loci of the Pectinolytic Plant Pathogenic Pectobacterium atrosepticum. Int J Mol Sci 2021; 22:ijms22094839. [PMID: 34063632 PMCID: PMC8125463 DOI: 10.3390/ijms22094839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/23/2021] [Accepted: 04/27/2021] [Indexed: 12/12/2022] Open
Abstract
Temperature is one of the critical factors affecting gene expression in bacteria. Despite the general interest in the link between bacterial phenotypes and environmental temperature, little is known about temperature-dependent gene expression in plant pathogenic Pectobacterium atrosepticum, a causative agent of potato blackleg and tuber soft rot worldwide. In this study, twenty-nine P. atrosepticum SCRI1043 thermoregulated genes were identified using Tn5-based transposon mutagenesis coupled with an inducible promotorless gusA gene as a reporter. From the pool of 29 genes, 14 were up-regulated at 18 °C, whereas 15 other genes were up-regulated at 28 °C. Among the thermoregulated loci, genes involved in primary bacterial metabolism, membrane-related proteins, fitness-corresponding factors, and several hypothetical proteins were found. The Tn5 mutants were tested for their pathogenicity in planta and for features that are likely to remain important for the pathogen to succeed in the (plant) environment. Five Tn5 mutants expressed visible phenotypes differentiating these mutants from the phenotype of the SCRI1043 wild-type strain. The gene disruptions in the Tn5 transposon mutants caused alterations in bacterial generation time, ability to form a biofilm, production of lipopolysaccharides, and virulence on potato tuber slices. The consequences of environmental temperature on the ability of P. atrosepticum to cause disease symptoms in potato are discussed.
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Zhou Y, Bu Z, Qian J, Chen Y, Qiao L, Yang S, Chen S, Wang X, Ren L, Yang Y. The UTP-glucose-1-phosphate uridylyltransferase of Brucella melitensis inhibits the activation of NF-κB via regulating the bacterial type IV secretion system. Int J Biol Macromol 2020; 164:3098-3104. [PMID: 32827613 DOI: 10.1016/j.ijbiomac.2020.08.134] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/12/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023]
Abstract
UDP-glucose pyrophosphorylase (UGPase) is an important pyrophosphatase that reversibly catalyzes the synthesis of UDP-glucose during glucose metabolism. We previously found that the deletion of UGPase may affect structure, growth, the virulence of Brucella, and the activation of cellular NF-κB. However, the exact mechanism of activation of NF-κB regulated by Brucella UGPase is still unclear. Here, we found for the first time that UGPase can regulate the expression of virB proteins (virB3, virB4, virB5, virB6, virB8, virB9, virB10, and virB11) of type IV secretion system (T4SS) as well as effectors (vceC, btpA, btpB, ricA, bspB, bspC, and bspF) of Brucella by promoting the expression of ribosomal S12 protein (rpsL), BMEI1825, and quinone of 2,4,5-trihydroxyphenylalanine (topA) proteins, and further inhibits the activation of cellular NF-κB and affects the virulence of Brucella. Our findings provide new insights into the mechanism used by Brucella to escape the immune recognition, which is expected to be of great value in the designing of Brucella vaccines and the screening of drug targets.
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Affiliation(s)
- Yucheng Zhou
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun 130112, China
| | - Zhaoyang Bu
- Military Veterinary Institute, Academy of Military Medical Sciences, Changchun 130112, China
| | - Jing Qian
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Yuening Chen
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun 130112, China
| | - Lianjiang Qiao
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun 130112, China
| | - Sen Yang
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun 130112, China
| | - Shipeng Chen
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun 130112, China
| | - Xinglong Wang
- Military Veterinary Institute, Academy of Military Medical Sciences, Changchun 130112, China
| | - Linzhu Ren
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Yanling Yang
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun 130112, China; Jilin Academy of Agricultural Sciences, Changchun 130033, China.
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Cools F, Triki D, Geerts N, Delputte P, Fourches D, Cos P. In vitro and in vivo Evaluation of in silico Predicted Pneumococcal UDPG:PP Inhibitors. Front Microbiol 2020; 11:1596. [PMID: 32760374 PMCID: PMC7373766 DOI: 10.3389/fmicb.2020.01596] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/18/2020] [Indexed: 11/25/2022] Open
Abstract
Pneumonia, of which Streptococcus pneumoniae is the most common causative agent, is considered one of the three top leading causes of death worldwide. As seen in other bacterial species, antimicrobial resistance is on the rise for this pathogen. Therefore, there is a pressing need for novel antimicrobial strategies to combat these infections. Recently, uridine diphosphate glucose pyrophosphorylase (UDPG:PP) has been put forward as a potential drug target worth investigating. Moreover, earlier research demonstrated that streptococci lacking a functional galU gene (encoding for UDPG:PP) were characterized by significantly reduced in vitro and in vivo virulence. Therefore, in this study we evaluated the anti-virulence activity of potential UDPG:PP inhibitors. They were selected in silico using a tailor-made streptococcal homology model, based on earlier listerial research. While the compounds didn’t affect bacterial growth, nor affected in vitro adhesion to and phagocytosis in macrophages, the amount of polysaccharide capsule was significantly reduced after co-incubation with these inhibitors. Moreover, co-incubation proved to have a positive effect on survival in an in vivo Galleria mellonella larval infection model. Therefore, rather than targeting bacterial survival directly, these compounds proved to have an effect on streptococcal virulence by lowering the amount of polysaccharide and thereby probably boosting recognition of this pathogen by the innate immune system. While the compounds need adaptation to broaden their activity to more streptococcal strains rather than being strain-specific, this study consolidates UDPG:PP as a potential novel drug target.
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Affiliation(s)
- Freya Cools
- Department of Pharmaceutical Sciences, Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Dhoha Triki
- Department of Chemistry, Bioinformatics Research Center, North Carolina State University, Raleigh, NC, United States
| | - Nele Geerts
- Department of Pharmaceutical Sciences, Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Peter Delputte
- Department of Pharmaceutical Sciences, Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Denis Fourches
- Department of Chemistry, Bioinformatics Research Center, North Carolina State University, Raleigh, NC, United States
| | - Paul Cos
- Department of Pharmaceutical Sciences, Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
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8
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Rooney WM, Grinter RW, Correia A, Parkhill J, Walker DC, Milner JJ. Engineering bacteriocin-mediated resistance against the plant pathogen Pseudomonas syringae. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:1296-1306. [PMID: 31705720 PMCID: PMC7152609 DOI: 10.1111/pbi.13294] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/16/2019] [Accepted: 10/27/2019] [Indexed: 05/20/2023]
Abstract
The plant pathogen, Pseudomonas syringae (Ps), together with related Ps species, infects and attacks a wide range of agronomically important crops, including tomato, kiwifruit, pepper, olive and soybean, causing economic losses. Currently, chemicals and introduced resistance genes are used to protect plants against these pathogens but have limited success and may have adverse environmental impacts. Consequently, there is a pressing need to develop alternative strategies to combat bacterial disease in crops. One such strategy involves using narrow-spectrum protein antibiotics (so-called bacteriocins), which diverse bacteria use to compete against closely related species. Here, we demonstrate that one bacteriocin, putidacin L1 (PL1), can be expressed in an active form at high levels in Arabidopsis and in Nicotiana benthamiana in planta to provide effective resistance against diverse pathovars of Ps. Furthermore, we find that Ps strains that mutate to acquire tolerance to PL1 lose their O-antigen, exhibit reduced motility and still cannot induce disease symptoms in PL1-transgenic Arabidopsis. Our results provide proof-of-principle that the transgene-mediated expression of a bacteriocin in planta can provide effective disease resistance to bacterial pathogens. Thus, the expression of bacteriocins in crops might offer an effective strategy for managing bacterial disease, in the same way that the genetic modification of crops to express insecticidal proteins has proven to be an extremely successful strategy for pest management. Crucially, nearly all genera of bacteria, including many plant pathogenic species, produce bacteriocins, providing an extensive source of these antimicrobial agents.
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Affiliation(s)
- William M. Rooney
- Plant Science GroupInstitute of Molecular, Cell and Systems Biology & School of Life SciencesUniversity of GlasgowGlasgowUK
- Institute of Infection, Immunity & InflammationCollege of Medical, Veterinary & Life SciencesUniversity of GlasgowGlasgowUK
| | - Rhys W. Grinter
- Institute of Infection, Immunity & InflammationCollege of Medical, Veterinary & Life SciencesUniversity of GlasgowGlasgowUK
- Present address:
School of Biological SciencesCentre for Geometric BiologyMonash UniversityClaytonVictoria3800Australia
| | - Annapaula Correia
- Wellcome Trust Sanger InstituteWellcome Trust Genome CampusHinxtonUK
- Present address:
Department of ZoologyUniversity of OxfordSouth Parks RoadOxfordOX1 3PSUK
| | - Julian Parkhill
- Wellcome Trust Sanger InstituteWellcome Trust Genome CampusHinxtonUK
- Present address:
Department of Veterinary MedicineUniversity of CambridgeMadingley RoadCambridgeCB3 0ESUK
| | - Daniel C. Walker
- Institute of Infection, Immunity & InflammationCollege of Medical, Veterinary & Life SciencesUniversity of GlasgowGlasgowUK
| | - Joel J. Milner
- Plant Science GroupInstitute of Molecular, Cell and Systems Biology & School of Life SciencesUniversity of GlasgowGlasgowUK
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Kutschera A, Schombel U, Wröbel M, Gisch N, Ranf S. Loss of wbpL disrupts O-polysaccharide synthesis and impairs virulence of plant-associated Pseudomonas strains. MOLECULAR PLANT PATHOLOGY 2019; 20:1535-1549. [PMID: 31559681 PMCID: PMC6804347 DOI: 10.1111/mpp.12864] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Despite its importance for membrane stability and pathogenicity of mammalian pathogens, functions of the O-polysaccharide (OPS) of lipopolysaccharide (LPS) remain unclear in plant-associated bacteria. Genetic information about OPS biosynthesis in these bacteria is largely missing. Genome analysis of various plant-associated Pseudomonas strains revealed that one of the two known OPS biosynthesis clusters from Pseudomonas aeruginosa PAO1, the common polysaccharide antigen (CPA) gene cluster, is only conserved in some strains of the Pseudomonas fluorescens group. For the O-specific antigen (OSA) biosynthesis cluster, the putative genomic position could be identified, but orthologues of most functional important OSA biosynthesis enzymes could not be detected. Nevertheless, orthologues of the glycosyltransferase WbpL, required for initiation of CPA and OSA synthesis in P. aeruginosa PAO1, could be identified in the analysed Pseudomonas genomes. Knockout mutations of wbpL orthologues in Pseudomonas syringae pv. tomato DC3000 (Pst) and Pseudomonas cichorii ATCC10857/DSM50259 (Pci) resulted in strains lacking the OPS. Infection experiments of Arabidopsis thaliana plants revealed a reduced entry into the leaf apoplast after spray inoculation and a reduced apoplastic amplification of Pst ∆wbpL. Stab and spray inoculation of lettuce (Lactuca sativa) leaves with Pci ∆wbpL causes reduced infection symptoms compared to the wild-type strain. Furthermore, swarming motility was reduced in ∆wbpL mutants of Pst and Pci. This might be a possible reason for reduced bacterial titres after surface inoculation and reduced bacterial amplification in the plant. Our results imply that the presence of lipopolysaccharide OPS is required for efficient host colonization and full virulence of plant-pathogenic Pseudomonas bacteria.
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Affiliation(s)
- Alexander Kutschera
- Technical University of MunichPhytopathology, TUM School of Life Sciences Weihenstephan85354Freising‐WeihenstephanGermany
| | - Ursula Schombel
- Research Center Borstel, Leibniz Lung CenterDivision of Bioanalytical Chemistry, Priority Area InfectionsParkallee 1‐4023845BorstelGermany
| | - Michelle Wröbel
- Research Center Borstel, Leibniz Lung CenterDivision of Bioanalytical Chemistry, Priority Area InfectionsParkallee 1‐4023845BorstelGermany
| | - Nicolas Gisch
- Research Center Borstel, Leibniz Lung CenterDivision of Bioanalytical Chemistry, Priority Area InfectionsParkallee 1‐4023845BorstelGermany
| | - Stefanie Ranf
- Technical University of MunichPhytopathology, TUM School of Life Sciences Weihenstephan85354Freising‐WeihenstephanGermany
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Ma Z, Liu JJ, Zamany A. Identification and Functional Characterization of an Effector Secreted by Cronartium ribicola. PHYTOPATHOLOGY 2019; 109:942-951. [PMID: 31066346 DOI: 10.1094/phyto-11-18-0427-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cri-9402 was identified as a protein effector from Cronartium ribicola, based on the effect of its expression on growth of Pseudomonas syringae Psm ES4326 introduced into transiently transformed tobacco leaves and stably transformed Arabidopsis seedlings. In tobacco leaves transiently expressing its coding sequence, growth of P. syringae Psm ES4326 was inhibited. Expression of pathogenesis-related (PR) protein 2 (PR2), PR4a, endochitinase B, hypersensitive-related 201 (HSR201), HSR203J, and proteinase inhibitor 1 was upregulated but expression of PR1, coronatine insensitive 1, and abscisic acid 1 was significantly suppressed. In transformed Arabidopsis seedlings, the effector stimulated growth of P. syringae Psm ES4326; significantly suppressed expression of PR1, PR2, nonexpresser of pathogenesis-related genes 1 (NPR1), NPR3, NPR4, phytoalexin deficient 4, and salicylic acid induction deficient 2; and enhanced expression of plant defensin 1.2 (PDF1.2). The above results showed that the majority of responses to this effector in tobacco leaves were converse to those in transformed Arabidopsis. We could conclude that Cri-9402 promoted disease resistance in tobacco leaves and disease susceptibility in Arabidopsis seedlings. Its transcript was mainly expressed in aeciospores of C. ribicola and was probably involved in production or germination of aeciospores, and it was an effector potentially functioning in white pine-blister rust interactions.
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Affiliation(s)
- Zhenguo Ma
- Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC V8Z 1M5, Canada
| | - Jun-Jun Liu
- Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC V8Z 1M5, Canada
| | - Arezoo Zamany
- Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC V8Z 1M5, Canada
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Magistro G, Magistro C, Stief CG, Schubert S. A simple and highly efficient method for gene silencing in Escherichia coli. J Microbiol Methods 2018; 154:25-32. [PMID: 30296471 DOI: 10.1016/j.mimet.2018.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/03/2018] [Accepted: 10/04/2018] [Indexed: 10/28/2022]
Abstract
Here we present a simple and rapidly achievable protocol for gene silencing in Escherichia coli (E. coli). In this procedure, antisense RNA (asRNA) of 400-nucleotides (nt) length and absolute complementarity to the target is produced by an expression plasmid. The designed asRNA should ideally cover at least the -10 site of the promoter and the Shine-Dalgarno sequence, and additional 300-bp of the following open reading frame of the target gene. We show that the transcription process of the target is not affected at all, whereas the translation process is impaired. Based on high constitutive expression of asRNA we were able to extend the silencing effect to knock-out levels. By inducible expression, we show that also the modulation is possible. This technique should be widely useful to study gene function in E. coli and other bacteria.
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Affiliation(s)
- Giuseppe Magistro
- Department of Urology, Ludwig-Maximilians-University, Munich, Germany.
| | - Christiane Magistro
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Munich, Germany
| | - Christian G Stief
- Department of Urology, Ludwig-Maximilians-University, Munich, Germany
| | - Sören Schubert
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Munich, Germany
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Moreira LM, Soares MR, Facincani AP, Ferreira CB, Ferreira RM, Ferro MIT, Gozzo FC, Felestrino ÉB, Assis RAB, Garcia CCM, Setubal JC, Ferro JA, de Oliveira JCF. Proteomics-based identification of differentially abundant proteins reveals adaptation mechanisms of Xanthomonas citri subsp. citri during Citrus sinensis infection. BMC Microbiol 2017; 17:155. [PMID: 28693412 PMCID: PMC5504864 DOI: 10.1186/s12866-017-1063-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/01/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Xanthomonas citri subsp. citri (Xac) is the causal agent of citrus canker. A proteomic analysis under in planta infectious and non-infectious conditions was conducted in order to increase our knowledge about the adaptive process of Xac during infection. RESULTS For that, a 2D-based proteomic analysis of Xac at 1, 3 and 5 days after inoculation, in comparison to Xac growth in NB media was carried out and followed by MALDI-TOF-TOF identification of 124 unique differentially abundant proteins. Among them, 79 correspond to up-regulated proteins in at least one of the three stages of infection. Our results indicate an important role of proteins related to biofilm synthesis, lipopolysaccharides biosynthesis, and iron uptake and metabolism as possible modulators of plant innate immunity, and revealed an intricate network of proteins involved in reactive oxygen species adaptation during Plants` Oxidative Burst response. We also identified proteins previously unknown to be involved in Xac-Citrus interaction, including the hypothetical protein XAC3981. A mutant strain for this gene has proved to be non-pathogenic in respect to classical symptoms of citrus canker induced in compatible plants. CONCLUSIONS This is the first time that a protein repertoire is shown to be active and working in an integrated manner during the infection process in a compatible host, pointing to an elaborate mechanism for adaptation of Xac once inside the plant.
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Affiliation(s)
- Leandro M Moreira
- Departamento de Ciências Biológicas (DECBI), Instituto de Ciências Exatas e Biológicas (ICEB), Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG, Brazil. .,Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
| | - Márcia R Soares
- Departamento de Bioquímica (DBq), Instituto de Química (IQ), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Agda P Facincani
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil.
| | - Cristiano B Ferreira
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil
| | - Rafael M Ferreira
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil
| | - Maria I T Ferro
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil
| | - Fábio C Gozzo
- Instituto de Química, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Érica B Felestrino
- Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - Renata A B Assis
- Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - Camila Carrião M Garcia
- Departamento de Ciências Biológicas (DECBI), Instituto de Ciências Exatas e Biológicas (ICEB), Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG, Brazil.,Núcleo de Pesquisas em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - João C Setubal
- Departamento de Bioquímica (DB), Instituto de Química (IQ), Universidade de São Paulo (USP), São Paulo, SP, Brazil.,Biocomplexity Institute, Virginia Tech, Blacksburg, VA, USA
| | - Jesus A Ferro
- Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP - Universidade Estadual Paulista, Departamento de Tecnologia, Jaboticabal, SP, Brazil
| | - Julio C F de Oliveira
- Departamento de Ciências Biológicas (DCB), Universidade Federal de São Paulo (UNIFESP), Diadema, SP, Brazil
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Zavala A, Kovacec V, Levín G, Moglioni A, Miranda MV, García E, Bonofiglio L, Mollerach M. Screening assay for inhibitors of a recombinant Streptococcus pneumoniae UDP-glucose pyrophosphorylase. J Enzyme Inhib Med Chem 2017; 32:203-207. [PMID: 28114831 PMCID: PMC6009895 DOI: 10.1080/14756366.2016.1247055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The UDP-glucose pyrophosphorylase of Streptococcus pneumoniae (GalUSpn) is absolutely required for the biosynthesis of capsular polysaccharide, the sine qua non virulence factor of pneumococcus. Since the eukaryotic enzymes are completely unrelated to their prokaryotic counterparts, we propose that the GalU enzyme is a critical target to fight the pneumococcal disease. A recombinant GalUSpn was overexpressed and purified. An enzymatic assay that is rapid, sensitive and easy to perform was developed. This assay was appropriate for screening chemical libraries for searching GalU inhibitors. This work represents a fundamental step in the exploration of novel antipneumococcal drugs.
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Affiliation(s)
- Agustín Zavala
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Verónica Kovacec
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Gustavo Levín
- b Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Biotecnología , Buenos Aires , Argentina
| | - Albertina Moglioni
- c Departamento de Farmacología, Facultad de Farmacia y Bioquímica , Cátedra de Química Medicinal, Universidad de Buenos Aires , Buenos Aires , Argentina
| | - María Victoria Miranda
- b Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Biotecnología , Buenos Aires , Argentina
| | - Ernesto García
- d Centro de Investigaciones Biológicas, CSIC and CIBER de Enfermedades Respiratorias (CIBERES) , Madrid , Spain
| | - Laura Bonofiglio
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Marta Mollerach
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
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Méndez JA, Mateos J, Beceiro A, Lopez M, Tomás M, Poza M, Bou G. Quantitative proteomic analysis of host--pathogen interactions: a study of Acinetobacter baumannii responses to host airways. BMC Genomics 2015; 16:422. [PMID: 26025090 PMCID: PMC4449591 DOI: 10.1186/s12864-015-1608-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 05/01/2015] [Indexed: 01/23/2023] Open
Abstract
Background Acinetobacter baumannii is a major health problem. The most common infection caused by A. baumannii is hospital acquired pneumonia, and the associated mortality rate is approximately 50 %. Neither in vivo nor ex vivo expression profiling has been performed at the proteomic or transcriptomic level for pneumonia caused by A. baumannii. In this study, we characterized the proteome of A. baumannii under conditions that simulate those found in the airways, to gain some insight into how A. baumannii adapts to the host and to improve knowledge about the pathogenesis and virulence of this bacterium. A clinical strain of A. baumannii was grown under different conditions: in the presence of bronchoalveolar lavage fluid from infected rats, of RAW 264.7 cells to simulate conditions in the respiratory tract and in control conditions. We used iTRAQ labelling and LC-MALDI-TOF/TOF to investigate how A. baumannii responds on exposure to macrophages/BALF. Results 179 proteins showed differential expression. In both models, proteins involved in the following processes were over-expressed: (i) pathogenesis and virulence (OmpA, YjjK); (ii) cell wall/membrane/envelope biogenesis (MurC); (iii) energy production and conversion (acetyl-CoA hydrolase); and (iv) translation (50S ribosomal protein L9). Proteins involved in the following were under-expressed: (i) lipid metabolism (short-chain dehydrogenase); (ii) amino acid metabolism and transport (aspartate aminotransferase); (iii) unknown function (DNA-binding protein); and (iv) inorganic ion transport and metabolism (hydroperoxidase). Conclusions We observed alterations in cell wall synthesis and identified 2 upregulated virulence-associated proteins with >15 peptides/protein in both ex vivo models (OmpA and YjjK), suggesting that these proteins are fundamental for pathogenesis and virulence in the airways. This study is the first comprehensive overview of the ex vivo proteome of A. baumannii and is an important step towards identification of diagnostic biomarkers, novel drug targets and potential vaccine candidates in the fight against pneumonia caused by A. baumannii. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1608-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jose Antonio Méndez
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Jesús Mateos
- Grupo de Proteomica-PBR2-ProteoRed/ISCIII-Servicio de Reumatologia, A Coruña, Spain.
| | - Alejandro Beceiro
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - María Lopez
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - María Tomás
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Margarita Poza
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Germán Bou
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
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The galU gene of Xanthomonas campestris pv. campestris is involved in bacterial attachment, cell motility, polysaccharide synthesis, virulence, and tolerance to various stresses. Arch Microbiol 2014; 196:729-38. [DOI: 10.1007/s00203-014-1012-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 06/11/2014] [Accepted: 07/04/2014] [Indexed: 12/12/2022]
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16
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Wulff NA, Zhang S, Setubal JC, Almeida NF, Martins EC, Harakava R, Kumar D, Rangel LT, Foissac X, Bové JM, Gabriel DW. The complete genome sequence of 'Candidatus Liberibacter americanus', associated with Citrus huanglongbing. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:163-76. [PMID: 24200077 DOI: 10.1094/mpmi-09-13-0292-r] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Liberibacter spp. form a Rhizobiaceae clade of phloem-limited pathogens of limited host range. Two obligately parasitic species have been sequenced: 'Candidatus Liberibacter asiaticus', which causes citrus huanglongbing (HLB) worldwide, and 'Ca. L. solanacearum', which causes potato "zebra chip" disease. A third (proposed) species, Liberibacter crescens, was isolated from mountain papaya, grown in axenic culture, and sequenced. In an effort to identify common host determinants, the complete genomic DNA sequence of a second HLB species, 'Ca. L. americanus' strain 'São Paulo' was determined. The circular genome of 1,195,201 bp had an average 31.12% GC content and 983 predicted protein encoding genes, 800 (81.4%) of which had a predicted function. There were 658 genes common to all sequenced Liberibacter spp. and only 8 genes common to 'Ca. L. americanus' and 'Ca. L. asiaticus' but not found in 'Ca. L. solanacearum'. Surprisingly, most of the lipopolysaccharide biosynthetic genes were missing from the 'Ca. L. americanus' genome, as well as OmpA and a key regulator of flagellin, all indicating a 'Ca. L. americanus' strategy of avoiding production of major pathogen-associated molecular patterns present in 'Ca. L. asiaticus' and 'Ca. L. solanacearum'. As with 'Ca. L. asiaticus', one of two 'Ca. L. americanus' prophages replicated as an excision plasmid and carried potential lysogenic conversion genes that appeared fragmentary or degenerated in 'Ca. L. solanacearum'.
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17
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Bogino PC, de las Mercedes Oliva M, Sorroche FG, Giordano W. The role of bacterial biofilms and surface components in plant-bacterial associations. Int J Mol Sci 2013; 14:15838-59. [PMID: 23903045 PMCID: PMC3759889 DOI: 10.3390/ijms140815838] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 06/18/2013] [Accepted: 06/28/2013] [Indexed: 01/09/2023] Open
Abstract
The role of bacterial surface components in combination with bacterial functional signals in the process of biofilm formation has been increasingly studied in recent years. Plants support a diverse array of bacteria on or in their roots, transport vessels, stems, and leaves. These plant-associated bacteria have important effects on plant health and productivity. Biofilm formation on plants is associated with symbiotic and pathogenic responses, but how plants regulate such associations is unclear. Certain bacteria in biofilm matrices have been found to induce plant growth and to protect plants from phytopathogens (a process termed biocontrol), whereas others are involved in pathogenesis. In this review, we systematically describe the various components and mechanisms involved in bacterial biofilm formation and attachment to plant surfaces and the relationships of these mechanisms to bacterial activity and survival.
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Affiliation(s)
- Pablo C. Bogino
- Department of Molecular Biology, National University of Río Cuarto, Ruta 36 Km 601, Río Cuarto, Córdoba X5804BYA, Argentina; E-Mails: (P.C.B.); (F.G.S.)
| | - María de las Mercedes Oliva
- Department of Microbiology and Immunology, National University of Río Cuarto, Ruta 36 Km 601, Córdoba X5804BYA, Argentina; E-Mail:
| | - Fernando G. Sorroche
- Department of Molecular Biology, National University of Río Cuarto, Ruta 36 Km 601, Río Cuarto, Córdoba X5804BYA, Argentina; E-Mails: (P.C.B.); (F.G.S.)
| | - Walter Giordano
- Department of Molecular Biology, National University of Río Cuarto, Ruta 36 Km 601, Río Cuarto, Córdoba X5804BYA, Argentina; E-Mails: (P.C.B.); (F.G.S.)
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18
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Schreiber KJ, Ye D, Fich E, Jian A, Lo T, Desveaux D. A high-throughput forward genetic screen identifies genes required for virulence of Pseudomonas syringae pv. maculicola ES4326 on Arabidopsis. PLoS One 2012; 7:e41461. [PMID: 22870224 PMCID: PMC3409859 DOI: 10.1371/journal.pone.0041461] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/21/2012] [Indexed: 12/11/2022] Open
Abstract
Successful pathogenesis requires a number of coordinated processes whose genetic bases remain to be fully characterized. We utilized a high-throughput, liquid media-based assay to screen transposon disruptants of the phytopathogen Pseudomonas syringae pv. maculicola ES4326 to identify genes required for virulence on Arabidopsis. Many genes identified through this screen were involved in processes such as type III secretion, periplasmic glucan biosynthesis, flagellar motility, and amino acid biosynthesis. A small set of genes did not fall into any of these functional groups, and their disruption resulted in context-specific effects on in planta bacterial growth.
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Affiliation(s)
- Karl J. Schreiber
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - David Ye
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Eric Fich
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Allen Jian
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Timothy Lo
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Darrell Desveaux
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada
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Li J, Wang N. The gpsX gene encoding a glycosyltransferase is important for polysaccharide production and required for full virulence in Xanthomonas citri subsp. citri. BMC Microbiol 2012; 12:31. [PMID: 22404966 PMCID: PMC3364877 DOI: 10.1186/1471-2180-12-31] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 03/09/2012] [Indexed: 02/08/2023] Open
Abstract
Background The Gram-negative bacterium Xanthomonas citri subsp. citri (Xac) causes citrus canker, one of the most destructive diseases of citrus worldwide. In our previous work, a transposon mutant of Xac strain 306 with an insertion in the XAC3110 locus was isolated in a screening that aimed at identifying genes related to biofilm formation. The XAC3110 locus was named as bdp24 for biofilm-defective phenotype and the mutant was observed to be affected in extracellular polysaccharide (EPS) and lipopolysaccharide (LPS) biosynthesis and cell motility. In this study, we further characterized the bdp24 (XAC3110) gene (designated as gpsX) using genetic complementation assays and expanded the knowledge about the function of the gpsX gene in Xac pathogenesis by investigating the roles of gpsX in EPS and LPS production, cell motility, biofilm formation on host leaves, stress tolerance, growth in planta, and host virulence of the citrus canker bacterium. Results The gpsX gene encodes a putative glycosyltransferase, which is highly conserved in the sequenced strains of Xanthomonas. Mutation of gpsX resulted in a significant reduction of the amount of EPS and loss of two LPS bands visualized on sodium dodecylsulphate- polyacrylamide gels. Biofilm assays revealed that the gpsX mutation affected biofilm formation by Xac on abiotic and biotic surfaces. The gpsX mutant showed delayed bacterial growth and caused reduced development of disease symptoms in susceptible citrus leaves. The gpsX mutant was more sensitive than the wild-type strain to various stresses, including the H2O2 oxidative stress. The mutant also showed attenuated ability in cell motility but not in flagellar formation. Quantitative reverse transcription-PCR assays indicated that mutation of gpsX did not affect the expression of virulence genes such as pthA in Xac strain 306. The affected phenotypes of the gpsX mutant could be complemented to wild-type levels by the intact gpsX gene. Conclusions Taken together, our data confirm that the gpsX gene is involved in EPS and LPS synthesis and biofilm formation in Xac and suggest that the gpsX gene contributes to the adaptation of Xac to the host microenvironments at early stage of infection and thus is required for full virulence on host plants.
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Affiliation(s)
- Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, IFAS, Lake Alfred, 33850, USA
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Erbs G, Newman MA. The role of lipopolysaccharide and peptidoglycan, two glycosylated bacterial microbe-associated molecular patterns (MAMPs), in plant innate immunity. MOLECULAR PLANT PATHOLOGY 2012; 13:95-104. [PMID: 21726397 PMCID: PMC6638628 DOI: 10.1111/j.1364-3703.2011.00730.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In an environment that is rich in potentially pathogenic microorganisms, the survival of higher eukaryotic organisms depends on efficient pathogen sensing and rapidly mounted defence responses. Such protective mechanisms are found in all multicellular organisms, and are collectively referred to as 'innate immunity'. Innate immunity is the first line of defence against invading microorganisms in vertebrates and the only line of defence in invertebrates and plants. Bacterial glycoconjugates, such as lipopolysaccharides (LPSs) from the outer membrane of Gram-negative bacteria and peptidoglycan (PGN) from the cell walls of both Gram-positive and Gram-negative bacteria, have been found to act as elicitors of plant innate immunity. These conserved, indispensable, microbe-specific molecules are also referred to as 'microbe-associated molecular patterns' (MAMPs). MAMPs are recognized by the plant innate immune system through the action of pattern recognition receptors (PRRs). A greater insight into the mechanisms of MAMP recognition and the description of PRRs for different microbial glycoconjugates will have considerable impact on the improvement of plant health and disease resistance. Here, the current knowledge about LPS and PGN as MAMPs is reviewed.
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Affiliation(s)
- Gitte Erbs
- University of Copenhagen, Department of Plant Biology and Biotechnology, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
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