The Experts below are selected from a list of 6075 Experts worldwide ranked by ideXlab platform

Alan Collmer - One of the best experts on this subject based on the ideXlab platform.

  • the pseudomonas syringae pv tomato hrpw protein has domains similar to harpins and pectate lyases and can elicit the plant hypersensitive response and bind to pectate
    Journal of Bacteriology, 1998
    Co-Authors: Amy O Charkowski, James R Alfano, Gail M Preston, Jing Yuan, Alan Collmer
    Abstract:

    The host-specific plant pathogen Pseudomonas syringae elicits the hypersensitive response (HR) in nonhost plants and secretes the HrpZ harpin in culture via the Hrp (type III) secretion system. Previous genetic evidence suggested the existence of another harpin gene in the P. syringae genome. hrpW was found in a region adjacent to the hrp cluster in P. syringae pv. tomato DC3000. hrpW encodes a 42. 9-kDa protein with domains resembling harpins and pectate lyases (Pels), respectively. HrpW has key properties of harpins. It is heat stable and glycine rich, lacks cysteine, is secreted by the Hrp system, and is able to elicit the HR when infiltrated into tobacco leaf tissue. The harpin domain (amino acids 1 to 186) has six glycine-rich repeats of a repeated sequence found in HrpZ, and a purified HrpW harpin domain fragment possessed HR elicitor Activity. In contrast, the HrpW Pel domain (amino acids 187 to 425) is similar to Pels from Nectria haematococca, Erwinia carotovora, Erwinia chrysanthemi, and Bacillus subtilis, and a purified Pel domain fragment did not elicit the HR. Neither this fragment nor the full-length HrpW showed Pel Activity in A230 assays under a variety of reaction conditions, but the Pel fragment bound to calcium pectate, a major constituent of the plant cell wall. The DNA sequence of the P. syringae pv. syringae B728a hrpW was also determined. The Pel domains of the two predicted HrpW proteins were 85% identical, whereas the harpin domains were only 53% identical. Sequences hybridizing at high stringency with the P. syringae pv. tomato hrpW were found in other P. syringae pathovars, Pseudomonas viridiflava, Ralstonia (Pseudomonas) solanacearum, and Xanthomonas campestris. DeltahrpZ::nptII or hrpW::OmegaSpr P. syringae pv. tomato mutants were little reduced in HR Elicitation Activity in tobacco, whereas this Activity was significantly reduced in a hrpZ hrpW double mutant. These features of hrpW and its product suggest that P. syringae produces multiple harpins and that the target of these proteins is in the plant cell wall.

  • analysis of the role of the pseudomonas syringae pv syringae hrpz harpin in Elicitation of the hypersensitive response in tobacco using functionally non polar hrpz deletion mutations truncated hrpz fragments and hrma mutations
    Molecular Microbiology, 1996
    Co-Authors: James R Alfano, David W Bauer, Timothy M Milos, Alan Collmer
    Abstract:

    Pseudomonas syringae pv. syringae, like many plant pathogenic bacteria, secretes a 'harpin' protein that can elicit the hypersensitive response (HR), a defensive cellular suicide, in non-host plants. The harpin-encoding hrpZ gene is located in an operon that also encodes Hrp secretion pathway components and is part of the functional cluster of hrp genes carried on cosmid pHIR11 that enables saprophytic bacteria like Escherichia coli and Pseudomonas fluorescens to elicit the HR in tobacco leaves. We have constructed functionally non-polar hrpZ deletion mutations, revealing that HrpZ is necessary for saprophytic bacteria carrying pHIR11 to elicit a typical HR, whereas it only enhances the Elicitation Activity of P. s. syringae. Partial deletion mutations revealed that the N-terminal 153 amino acids of HrpZ can enable E. coli MC4100-(pHIR11) to elicit a strong HR. hrpZ subclone products comprising the N-terminal 109 amino acids and C-terminal 216 amino acids, respectively, of the 341 amino acid protein were isolated and found to elicit the HR. P. fluorescens (pHIR11 hrmA::TnphoA) mutants do not elicit the HR, but cell fractionation and immunoblot analysis revealed that they produce and secrete wild-type levels of HrpZ. Therefore, elicitor Activity resides in multiple regions of HrpZ, P. syringae produces elicitor(s) in addition to HrpZ, and HrpZ is essential but not sufficient for HR Elicitation by saprophytic bacteria carrying pHIR11.

James R Alfano - One of the best experts on this subject based on the ideXlab platform.

  • the pseudomonas syringae pv tomato hrpw protein has domains similar to harpins and pectate lyases and can elicit the plant hypersensitive response and bind to pectate
    Journal of Bacteriology, 1998
    Co-Authors: Amy O Charkowski, James R Alfano, Gail M Preston, Jing Yuan, Alan Collmer
    Abstract:

    The host-specific plant pathogen Pseudomonas syringae elicits the hypersensitive response (HR) in nonhost plants and secretes the HrpZ harpin in culture via the Hrp (type III) secretion system. Previous genetic evidence suggested the existence of another harpin gene in the P. syringae genome. hrpW was found in a region adjacent to the hrp cluster in P. syringae pv. tomato DC3000. hrpW encodes a 42. 9-kDa protein with domains resembling harpins and pectate lyases (Pels), respectively. HrpW has key properties of harpins. It is heat stable and glycine rich, lacks cysteine, is secreted by the Hrp system, and is able to elicit the HR when infiltrated into tobacco leaf tissue. The harpin domain (amino acids 1 to 186) has six glycine-rich repeats of a repeated sequence found in HrpZ, and a purified HrpW harpin domain fragment possessed HR elicitor Activity. In contrast, the HrpW Pel domain (amino acids 187 to 425) is similar to Pels from Nectria haematococca, Erwinia carotovora, Erwinia chrysanthemi, and Bacillus subtilis, and a purified Pel domain fragment did not elicit the HR. Neither this fragment nor the full-length HrpW showed Pel Activity in A230 assays under a variety of reaction conditions, but the Pel fragment bound to calcium pectate, a major constituent of the plant cell wall. The DNA sequence of the P. syringae pv. syringae B728a hrpW was also determined. The Pel domains of the two predicted HrpW proteins were 85% identical, whereas the harpin domains were only 53% identical. Sequences hybridizing at high stringency with the P. syringae pv. tomato hrpW were found in other P. syringae pathovars, Pseudomonas viridiflava, Ralstonia (Pseudomonas) solanacearum, and Xanthomonas campestris. DeltahrpZ::nptII or hrpW::OmegaSpr P. syringae pv. tomato mutants were little reduced in HR Elicitation Activity in tobacco, whereas this Activity was significantly reduced in a hrpZ hrpW double mutant. These features of hrpW and its product suggest that P. syringae produces multiple harpins and that the target of these proteins is in the plant cell wall.

  • analysis of the role of the pseudomonas syringae pv syringae hrpz harpin in Elicitation of the hypersensitive response in tobacco using functionally non polar hrpz deletion mutations truncated hrpz fragments and hrma mutations
    Molecular Microbiology, 1996
    Co-Authors: James R Alfano, David W Bauer, Timothy M Milos, Alan Collmer
    Abstract:

    Pseudomonas syringae pv. syringae, like many plant pathogenic bacteria, secretes a 'harpin' protein that can elicit the hypersensitive response (HR), a defensive cellular suicide, in non-host plants. The harpin-encoding hrpZ gene is located in an operon that also encodes Hrp secretion pathway components and is part of the functional cluster of hrp genes carried on cosmid pHIR11 that enables saprophytic bacteria like Escherichia coli and Pseudomonas fluorescens to elicit the HR in tobacco leaves. We have constructed functionally non-polar hrpZ deletion mutations, revealing that HrpZ is necessary for saprophytic bacteria carrying pHIR11 to elicit a typical HR, whereas it only enhances the Elicitation Activity of P. s. syringae. Partial deletion mutations revealed that the N-terminal 153 amino acids of HrpZ can enable E. coli MC4100-(pHIR11) to elicit a strong HR. hrpZ subclone products comprising the N-terminal 109 amino acids and C-terminal 216 amino acids, respectively, of the 341 amino acid protein were isolated and found to elicit the HR. P. fluorescens (pHIR11 hrmA::TnphoA) mutants do not elicit the HR, but cell fractionation and immunoblot analysis revealed that they produce and secrete wild-type levels of HrpZ. Therefore, elicitor Activity resides in multiple regions of HrpZ, P. syringae produces elicitor(s) in addition to HrpZ, and HrpZ is essential but not sufficient for HR Elicitation by saprophytic bacteria carrying pHIR11.

Pascale Goupil - One of the best experts on this subject based on the ideXlab platform.

  • Effect of acibenzolar-S-methyl phototransformation on its Elicitation Activity in tobacco cells.
    Plant physiology and biochemistry : PPB, 2017
    Co-Authors: Florent Lavergne, Claire Richard, Marc Saudreau, Jean-stéphane Venisse, Boris Fumanal, Pascale Goupil
    Abstract:

    Abstract The plant activator acibenzolar-S-methyl (BTH) undergoes phototransformation when exposed to solar radiation. Here we investigated the changes in its Elicitation properties on BY-2 tobacco cells at different stages of the photochemical reaction. Both pure BTH and formulated BTH were irradiated in controlled conditions to achieve different extents of conversion. Both pure BTH (900 μM) and Bion® (0.4 g.L−1) induced BY-2 cell death, but BTH photoconverted to an extent of 25 ± 3% lowered the cell death rate. A kinetic study of β-1,3-glucanase and chitinase activities was conducted on BY-2 extracellular medium. Exposure of tobacco cells to either pure BTH or Bion® resulted in a significant increase in the activities of both defense enzymes, which peaked 48 h after the treatment. The pathogenesis-related (PR) protein activities were quantified 48 h after Elicitation for a range of phototransformed BTH solutions. The enzyme activities were reduced when BY-2 cells were treated with solutions in which BTH conversion was 22 ± 3%, 42 ± 3% and 100 ± 3%, but were not affected by the solution in which BTH was phototransformed at 60%, suggesting that some of the secondary photoproducts also exhibit eliciting properties. Solar irradiation of BTH thus impairs its Elicitation properties, but this impairment depends strongly on the extent of phototransformation.

  • Effect of acibenzolar-S-methyl phototransformation on its Elicitation Activity in tobacco cells
    Plant Physiology and Biochemistry, 2017
    Co-Authors: Florent Lavergne, Claire Richard, Marc Saudreau, Jean-stéphane Venisse, Boris Fumanal, Pascale Goupil
    Abstract:

    The plant activator acibenzolar-S-methyl (BTH) undergoes phototransformation when exposed to solar radiation. Here we investigated the changes in its Elicitation properties on BY-2 tobacco cells at different stages of the photochemical reaction. Both pure BTH and formulated BTH were irradiated in controlled conditions to achieve different extents of conversion. Both pure BTH (900 mu,M) and Bion (R) (0.4 g.L-1) induced BY-2 cell death, but BTH photoconverted to an extent of 25 +/- 3% lowered the cell death rate. A kinetic study of beta-1,3-glucanase and chitinase activities was conducted on BY-2 extracellular medium. Exposure of tobacco cells to either pure BTH or Bion (R) resulted in a significant increase in the activities of both defense enzymes, which peaked 48 h after the treatment. The pathogenesis-related (PR) protein activities were quantified 48 h after Elicitation for a range of phototransformed BTH solutions. The enzyme activities were reduced when BY-2 cells were treated with solutions in which BTH conversion was 22 +/- 3%, 42 +/- 3% and 100 +/- 3%, but were not affected by the solution in which BTH was photo transformed at 60%, suggesting that some of the secondary photoproducts also exhibit eliciting properties. Solar irradiation of BTH thus impairs its Elicitation properties, but this impairment depends strongly on the extent of phototransformation. (C) 2017 Elsevier Masson SAS. All rights reserved.

Florent Lavergne - One of the best experts on this subject based on the ideXlab platform.

  • Effect of acibenzolar-S-methyl phototransformation on its Elicitation Activity in tobacco cells.
    Plant physiology and biochemistry : PPB, 2017
    Co-Authors: Florent Lavergne, Claire Richard, Marc Saudreau, Jean-stéphane Venisse, Boris Fumanal, Pascale Goupil
    Abstract:

    Abstract The plant activator acibenzolar-S-methyl (BTH) undergoes phototransformation when exposed to solar radiation. Here we investigated the changes in its Elicitation properties on BY-2 tobacco cells at different stages of the photochemical reaction. Both pure BTH and formulated BTH were irradiated in controlled conditions to achieve different extents of conversion. Both pure BTH (900 μM) and Bion® (0.4 g.L−1) induced BY-2 cell death, but BTH photoconverted to an extent of 25 ± 3% lowered the cell death rate. A kinetic study of β-1,3-glucanase and chitinase activities was conducted on BY-2 extracellular medium. Exposure of tobacco cells to either pure BTH or Bion® resulted in a significant increase in the activities of both defense enzymes, which peaked 48 h after the treatment. The pathogenesis-related (PR) protein activities were quantified 48 h after Elicitation for a range of phototransformed BTH solutions. The enzyme activities were reduced when BY-2 cells were treated with solutions in which BTH conversion was 22 ± 3%, 42 ± 3% and 100 ± 3%, but were not affected by the solution in which BTH was phototransformed at 60%, suggesting that some of the secondary photoproducts also exhibit eliciting properties. Solar irradiation of BTH thus impairs its Elicitation properties, but this impairment depends strongly on the extent of phototransformation.

  • Effect of acibenzolar-S-methyl phototransformation on its Elicitation Activity in tobacco cells
    Plant Physiology and Biochemistry, 2017
    Co-Authors: Florent Lavergne, Claire Richard, Marc Saudreau, Jean-stéphane Venisse, Boris Fumanal, Pascale Goupil
    Abstract:

    The plant activator acibenzolar-S-methyl (BTH) undergoes phototransformation when exposed to solar radiation. Here we investigated the changes in its Elicitation properties on BY-2 tobacco cells at different stages of the photochemical reaction. Both pure BTH and formulated BTH were irradiated in controlled conditions to achieve different extents of conversion. Both pure BTH (900 mu,M) and Bion (R) (0.4 g.L-1) induced BY-2 cell death, but BTH photoconverted to an extent of 25 +/- 3% lowered the cell death rate. A kinetic study of beta-1,3-glucanase and chitinase activities was conducted on BY-2 extracellular medium. Exposure of tobacco cells to either pure BTH or Bion (R) resulted in a significant increase in the activities of both defense enzymes, which peaked 48 h after the treatment. The pathogenesis-related (PR) protein activities were quantified 48 h after Elicitation for a range of phototransformed BTH solutions. The enzyme activities were reduced when BY-2 cells were treated with solutions in which BTH conversion was 22 +/- 3%, 42 +/- 3% and 100 +/- 3%, but were not affected by the solution in which BTH was photo transformed at 60%, suggesting that some of the secondary photoproducts also exhibit eliciting properties. Solar irradiation of BTH thus impairs its Elicitation properties, but this impairment depends strongly on the extent of phototransformation. (C) 2017 Elsevier Masson SAS. All rights reserved.

Amy O Charkowski - One of the best experts on this subject based on the ideXlab platform.

  • the pseudomonas syringae pv tomato hrpw protein has domains similar to harpins and pectate lyases and can elicit the plant hypersensitive response and bind to pectate
    Journal of Bacteriology, 1998
    Co-Authors: Amy O Charkowski, James R Alfano, Gail M Preston, Jing Yuan, Alan Collmer
    Abstract:

    The host-specific plant pathogen Pseudomonas syringae elicits the hypersensitive response (HR) in nonhost plants and secretes the HrpZ harpin in culture via the Hrp (type III) secretion system. Previous genetic evidence suggested the existence of another harpin gene in the P. syringae genome. hrpW was found in a region adjacent to the hrp cluster in P. syringae pv. tomato DC3000. hrpW encodes a 42. 9-kDa protein with domains resembling harpins and pectate lyases (Pels), respectively. HrpW has key properties of harpins. It is heat stable and glycine rich, lacks cysteine, is secreted by the Hrp system, and is able to elicit the HR when infiltrated into tobacco leaf tissue. The harpin domain (amino acids 1 to 186) has six glycine-rich repeats of a repeated sequence found in HrpZ, and a purified HrpW harpin domain fragment possessed HR elicitor Activity. In contrast, the HrpW Pel domain (amino acids 187 to 425) is similar to Pels from Nectria haematococca, Erwinia carotovora, Erwinia chrysanthemi, and Bacillus subtilis, and a purified Pel domain fragment did not elicit the HR. Neither this fragment nor the full-length HrpW showed Pel Activity in A230 assays under a variety of reaction conditions, but the Pel fragment bound to calcium pectate, a major constituent of the plant cell wall. The DNA sequence of the P. syringae pv. syringae B728a hrpW was also determined. The Pel domains of the two predicted HrpW proteins were 85% identical, whereas the harpin domains were only 53% identical. Sequences hybridizing at high stringency with the P. syringae pv. tomato hrpW were found in other P. syringae pathovars, Pseudomonas viridiflava, Ralstonia (Pseudomonas) solanacearum, and Xanthomonas campestris. DeltahrpZ::nptII or hrpW::OmegaSpr P. syringae pv. tomato mutants were little reduced in HR Elicitation Activity in tobacco, whereas this Activity was significantly reduced in a hrpZ hrpW double mutant. These features of hrpW and its product suggest that P. syringae produces multiple harpins and that the target of these proteins is in the plant cell wall.