This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Morello, J. E.
Right arrow Articles by Collmer, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Morello, J. E.
Right arrow Articles by Collmer, A.

 Previous Article  |  Next Article 

Journal of Bacteriology, May 2009, p. 3120-3131, Vol. 191, No. 9
0021-9193/09/$08.00+0     doi:10.1128/JB.01623-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Pseudomonas syringae HrpP Is a Type III Secretion Substrate Specificity Switch Domain Protein That Is Translocated into Plant Cells but Functions Atypically for a Substrate-Switching Protein {triangledown}

Joanne E. Morello and Alan Collmer*

Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853

Received 14 November 2008/ Accepted 23 February 2009

Pseudomonas syringae delivers virulence effector proteins into plant cells via an Hrp1 type III secretion system (T3SS). P. syringae pv. tomato DC3000 HrpP has a C-terminal, putative T3SS substrate specificity switch domain, like Yersinia YscP. A {Delta}hrpP DC3000 mutant could not cause disease in tomato or elicit a hypersensitive response (HR) in tobacco, but the HR could be restored by expression of HrpP in trans. Though HrpP is a relatively divergent protein in the T3SS of different P. syringae pathovars, hrpP from P. syringae pv. syringae 61 and P. syringae pv. phaseolicola 1448A restored HR elicitation and pathogenicity to DC3000 {Delta}hrpP. HrpP was translocated into Nicotiana benthamiana cells via the DC3000 T3SS when expressed from its native promoter, but it was not secreted in culture. N- and C-terminal truncations of HrpP were tested for their ability to be translocated and to restore HR elicitation activity to the {Delta}hrpP mutant. No N-terminal truncation completely abolished translocation, implying that HrpP has an atypical T3SS translocation signal. Deleting more than 20 amino acids from the C terminus abolished the ability to restore HR elicitation. HrpP fused to green fluorescent protein was no longer translocated but could restore HR elicitation activity to the {Delta}hrpP mutant, suggesting that translocation is not essential for the function of HrpP. No T3SS substrates were detectably secreted by DC3000 {Delta}hrpP except the pilin subunit HrpA, which unexpectedly was secreted poorly. HrpP may function somewhat differently than YscP because the P. syringae T3SS pilus likely varies in length due to differing plant cell walls.

* Corresponding author. Mailing address: Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853. Phone: (607) 255-7843. Fax: (607) 255-4471. E-mail: arc2{at}cornell.edu

{triangledown} Published ahead of print on 6 March 2009.

Journal of Bacteriology, May 2009, p. 3120-3131, Vol. 191, No. 9
0021-9193/09/$08.00+0     doi:10.1128/JB.01623-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Buttner, D., He, S. Y. (2009). Type III Protein Secretion in Plant Pathogenic Bacteria. Plant Physiol. 150: 1656-1664 [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»