The Genome of Pseudomonas syringae Tomato DC3000 and Functional Genomic Studies to Better Understand Plant Pathogenesis

Jamir, Yashitola; Tang, Xiaoyan; Alfano, James R.

doi:10.1007/978-1-4419-9086-0_4

Cited by 2 publications

(2 citation statements)

References 104 publications

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“…Thus, identification by avirulence assays involving test plants carrying cognate R genes has been the historical approach. Genomic sequencing facilitates comprehensive searches based on Hrp promoter activity, on translocation of transposon-generated reporter protein fusions into plant cells, or on sequence patterns associated with Hrp promoters and TTSS targeting domains (33,41,67,80).…”

Section: Ttss Effectors: Functional and Comparative Genomics Identifymentioning

confidence: 99%

TYPE III SECRETION SYSTEM EFFECTOR PROTEINS: Double Agents in Bacterial Disease and Plant Defense

Alfano

Collmer

2004

Annu. Rev. Phytopathol.

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691

535

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Many phytopathogenic bacteria inject virulence effector proteins into plant cells via a Hrp type III secretion system (TTSS). Without the TTSS, these pathogens cannot defeat basal defenses, grow in plants, produce disease lesions in hosts, or elicit the hypersensitive response (HR) in nonhosts. Pathogen genome projects employing bioinformatic methods to identify TTSS Hrp regulon promoters and TTSS pathway targeting signals suggest that phytopathogenic Pseudomonas, Xanthomonas, and Ralstonia spp. harbor large arsenals of effectors. The Hrp TTSS employs customized cytoplasmic chaperones, conserved export components in the bacterial envelope (also used by the TTSS of animal pathogens), and a more specialized set of TTSS-secreted proteins to deliver effectors across the plant cell wall and plasma membrane. Many effectors can act as molecular double agents that betray the pathogen to plant defenses in some interactions and suppress host defenses in others. Investigations of the functions of effectors within plant cells have demonstrated the plasma membrane and nucleus as subcellular sites for several effectors, revealed some effectors to possess cysteine protease or protein tyrosine phosphatase activity, and provided new clues to the coevolution of bacterium-plant interactions.

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Section: Ttss Effectors: Functional and Comparative Genomics Identifymentioning

confidence: 99%

TYPE III SECRETION SYSTEM EFFECTOR PROTEINS: Double Agents in Bacterial Disease and Plant Defense

Alfano

Collmer

2004

Annu. Rev. Phytopathol.

Self Cite

691

535

View full text Add to dashboard Cite

show abstract

“…This increases the confirmed inventory of DC3000 Hops to 43. It is likely that the inventory will reach about 50 Hops, because several other candidate Hops await testing (21,43). We have used several methods to identify hop genes, including searches for hrp promoter and N-terminal secretion signal characteristics (30,59).…”

Section: Discussionmentioning

confidence: 99%

Pseudomonas syringae Type III Chaperones ShcO1, ShcS1, and ShcS2 Facilitate Translocation of Their Cognate Effectors and Can Substitute for Each Other in the Secretion of HopO1-1

Guo¹,

Chancey²,

Tian³

et al. 2005

J Bacteriol

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The Pseudomonas syringae type III secretion system (TTSS) translocates effector proteins into plant cells. Several P. syringae effectors require accessory proteins called type III chaperones (TTCs) to be secreted via the TTSS. We characterized the hopO1-1, hopS1, and hopS2 operons in P. syringae pv. tomato DC3000; these operons encode three homologous TTCs, ShcO1, ShcS1, and ShcS2. ShcO1, ShcS1, and ShcS2 facilitated the type III secretion and/or translocation of their cognate effectors HopO1-1, HopS1, and HopS2, respectively. ShcO1 and HopO1-1 interacted with each other in yeast two-hybrid and coimmunoprecipitation assays. Interestingly, ShcS1 and ShcS2 were capable of substituting for ShcO1 in facilitating HopO1-1 secretion and translocation and each TTC was able to bind the other's cognate effectors in yeast two-hybrid assays. Moreover, ShcO1, ShcS1, and ShcS2 all bound to the middle-third region of HopO1-1. The HopS2 effector possessed atypical P. syringae TTSS N-terminal characteristics and was translocated in low amounts. A site-directed HopS2 mutation that introduced a common N-terminal characteristic from other P. syringae type III secreted substrates increased HopS2 translocation, supporting the idea that this characteristic functions as a secretion signal. Additionally, hopO1-2 and hopT1-2 were shown to encode effectors secreted via the DC3000 TTSS. Finally, a DC3000 hopO1-1 operon deletion mutant produced disease symptoms similar to those seen with wild-type DC3000 but was reduced in its ability to multiply in Arabidopsis thaliana. The existence of TTCs that can bind to dissimilar effectors and that can substitute for each other in effector secretion provides insights into the nature of how TTCs function.

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The Genome of Pseudomonas syringae Tomato DC3000 and Functional Genomic Studies to Better Understand Plant Pathogenesis

Cited by 2 publications

References 104 publications

TYPE III SECRETION SYSTEM EFFECTOR PROTEINS: Double Agents in Bacterial Disease and Plant Defense

TYPE III SECRETION SYSTEM EFFECTOR PROTEINS: Double Agents in Bacterial Disease and Plant Defense

Pseudomonas syringae Type III Chaperones ShcO1, ShcS1, and ShcS2 Facilitate Translocation of Their Cognate Effectors and Can Substitute for Each Other in the Secretion of HopO1-1

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