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The Pseudomonas syringae type III effector tyrosine phosphatase HopAO1 suppresses innate immunity in Arabidopsis thaliana.

Publication ,  Journal Article
Underwood, W; Zhang, S; He, SY
Published in: The Plant journal : for cell and molecular biology
November 2007

The bacterial pathogen Pseudomonas syringae pv. tomato (Pst) strain DC3000 infects tomato and Arabidopsis plants, and is a model for studying the molecular basis of bacterial disease. Pst DC3000 secretes a battery of largely uncharacterized effector proteins into host cells via a type-III secretion system (TTSS). Little is currently known about the molecular mechanisms by which individual TTSS effectors promote virulence. The effector HopAO1 has similarity to protein tyrosine phosphatases, including a conserved catalytic site, and suppresses the hypersensitive response (HR) in some non-host plants. Whether HopAO1 has a similar effect in the host Arabidopsis is not clear. Here, we show that transgenic expression of HopAO1 in Arabidopsis suppresses callose deposition elicited by the Pst DC3000 hrpA mutant, and allows the normally non-pathogenic hrpA mutant to multiply within the leaf tissue. HopAO1 also suppresses resistance to Pst DC3000 induced by flg22, a pathogen-associated molecular pattern (PAMP). However, HopAO1 does not suppress the HR triggered by several classical avirulence genes. These results suggest that HopAO1 targets primarily PAMP-induced innate immunity in Arabidopsis. The virulence function of HopAO1 is dependent on an intact phosphatase catalytic site, as transgenic plants expressing a catalytically inactive derivative do not show these effects. Intriguingly, expression of the catalytically inactive HopAO1 has a dominant-negative effect on the function of the wild-type HopAO1. Analysis of mitogen-activated protein kinase (MAPK) activity suggests that HopAO1 targets a step downstream or independent of MAPK activation. Genome-wide expression analysis revealed that expression of several well-known defense genes was suppressed in hrpA mutant-infected HopAO1 transgenic plants.

Duke Scholars

Published In

The Plant journal : for cell and molecular biology

DOI

EISSN

1365-313X

ISSN

0960-7412

Publication Date

November 2007

Volume

52

Issue

4

Start / End Page

658 / 672

Related Subject Headings

  • Virulence
  • Pseudomonas syringae
  • Protein Tyrosine Phosphatases
  • Plants, Genetically Modified
  • Plant Biology & Botany
  • Oligonucleotide Array Sequence Analysis
  • Mutagenesis, Site-Directed
  • Immunity, Innate
  • Host-Pathogen Interactions
  • Gene Expression Regulation, Plant
 

Citation

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Underwood, W., Zhang, S., & He, S. Y. (2007). The Pseudomonas syringae type III effector tyrosine phosphatase HopAO1 suppresses innate immunity in Arabidopsis thaliana. The Plant Journal : For Cell and Molecular Biology, 52(4), 658–672. https://doi.org/10.1111/j.1365-313x.2007.03262.x
Underwood, William, Shuqun Zhang, and Sheng Y. He. “The Pseudomonas syringae type III effector tyrosine phosphatase HopAO1 suppresses innate immunity in Arabidopsis thaliana.The Plant Journal : For Cell and Molecular Biology 52, no. 4 (November 2007): 658–72. https://doi.org/10.1111/j.1365-313x.2007.03262.x.
Underwood W, Zhang S, He SY. The Pseudomonas syringae type III effector tyrosine phosphatase HopAO1 suppresses innate immunity in Arabidopsis thaliana. The Plant journal : for cell and molecular biology. 2007 Nov;52(4):658–72.
Underwood, William, et al. “The Pseudomonas syringae type III effector tyrosine phosphatase HopAO1 suppresses innate immunity in Arabidopsis thaliana.The Plant Journal : For Cell and Molecular Biology, vol. 52, no. 4, Nov. 2007, pp. 658–72. Epmc, doi:10.1111/j.1365-313x.2007.03262.x.
Underwood W, Zhang S, He SY. The Pseudomonas syringae type III effector tyrosine phosphatase HopAO1 suppresses innate immunity in Arabidopsis thaliana. The Plant journal : for cell and molecular biology. 2007 Nov;52(4):658–672.
Journal cover image

Published In

The Plant journal : for cell and molecular biology

DOI

EISSN

1365-313X

ISSN

0960-7412

Publication Date

November 2007

Volume

52

Issue

4

Start / End Page

658 / 672

Related Subject Headings

  • Virulence
  • Pseudomonas syringae
  • Protein Tyrosine Phosphatases
  • Plants, Genetically Modified
  • Plant Biology & Botany
  • Oligonucleotide Array Sequence Analysis
  • Mutagenesis, Site-Directed
  • Immunity, Innate
  • Host-Pathogen Interactions
  • Gene Expression Regulation, Plant