Interplay among Pseudomonas syringae HrpR, HrpS and HrpV proteins for regulation of the type III secretion system
Version of Record online: 19 JUN 2014
© 2014 The Authors. FEMS Microbiology Letters published by John Wiley & Sons Ltd on behalf of Federation of European Microbiological Societies.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
FEMS Microbiology Letters
Special Issue: Pseudomonas
Volume 356, Issue 2, pages 201–211, July 2014
How to Cite
Jovanovic, M., Lawton, E., Schumacher, J. and Buck, M. (2014), Interplay among Pseudomonas syringae HrpR, HrpS and HrpV proteins for regulation of the type III secretion system. FEMS Microbiology Letters, 356: 201–211. doi: 10.1111/1574-6968.12476
- Issue online: 24 JUL 2014
- Version of Record online: 19 JUN 2014
- Accepted manuscript online: 26 MAY 2014 04:09AM EST
- Manuscript Accepted: 16 MAY 2014
- Manuscript Revised: 15 MAY 2014
- Manuscript Received: 7 FEB 2014
- Leverhulme Trust. Grant Number: F/07 058/BM
Pseudomonas syringae pv. tomato DC3000, a plant pathogenic gram-negative bacterium, employs the type III secretion system (T3SS) to cause disease in tomato and Arabidopsis and to induce the hypersensitive response in nonhost plants. The expression of T3SS is regulated by the HrpL extracytoplasmic sigma factor. Expression of HrpL is controlled by transcriptional activators HrpR and HrpS and negative regulator HrpV. In this study, we analysed the organization of HrpRS and HrpV regulatory proteins and interplay between them. We identified one key residue I26 in HrpS required for repression by HrpV. Substitution of I26 in HrpS abolishes its interaction with HrpV and impairs interactions between HrpS and HrpR and the self-association of HrpS. We show that HrpS self-associates and can associate simultaneously with HrpR and HrpV. We now propose that HrpS has a central role in the assembly of the regulatory HrpRSV complex. Deletion analysis of HrpR and HrpS proteins showed that C-terminal parts of HrpR and HrpS confer determinants indispensable for their self-assembly.