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

 Previous Article  |  Next Article 

Journal of Bacteriology, September 2004, p. 6015-6024, Vol. 186, No. 18
0021-9193/04/$08.00+0     DOI: 10.1128/JB.186.18.6015-6024.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Involvement of a Plasmid-Encoded Type IV Secretion System in the Plant Tissue Watersoaking Phenotype of Burkholderia cenocepacia

Amanda S. Engledow,¹ Enrique G. Medrano,^1, Eshwar Mahenthiralingam,² John J. LiPuma,³ and Carlos F. Gonzalez^1*

Department of Plant Pathology & Microbiology, Texas A&M University, College Station, Texas,¹ Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom,² Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan³

Received 23 April 2004/ Accepted 16 June 2004

Burkholderia cenocepacia strain K56-2, a representative of the Burkholderia cepacia complex, is part of the epidemic and clinically problematic ET12 lineage. The strain produced plant tissue watersoaking (ptw) on onion tissue, which is a plant disease-associated trait. Using plasposon mutagenesis, mutants in the ptw phenotype were generated. The translated sequence of a disrupted gene (ptwD4) from a ptw-negative mutant showed homology to VirD4-like proteins. Analysis of the region proximal to the transfer gene homolog identified a gene cluster located on the 92-kb resident plasmid that showed homology to type IV secretion systems. The role of ptwD4, ptwC, ptwB4, and ptwB10 in the expression of ptw activity was determined by conducting site-directed mutagenesis. The ptw phenotype was not expressed by K56-2 derivatives with a disruption in ptwD4, ptwB4, or ptwB10 but was observed in a derivative with a disruption in ptwC. Complementation of ptw-negative K56-2 derivatives in trans resulted in complete restoration of the ptw phenotype. In addition, analysis of culture supernatants revealed that the putative ptw effector(s) was a secreted, heat-stable protein(s) that caused plasmolysis of plant protoplasts. A second chromosomally encoded type IV secretion system with complete homology to the VirB-VirD system was identified in K56-2. Site-directed mutagenesis of key secretory genes in the VirB-VirD system did not affect expression of the ptw phenotype. Our findings indicate that in strain K56-2, the plasmid-encoded Ptw type IV secretion system is responsible for the secretion of a plant cytotoxic protein(s).

Present address: Cotton Pathology Research Laboratory, USDA, ARS, SPARC, College Station, TX 77845.

This article has been cited by other articles:

• Jacobs, J. L., Fasi, A. C., Ramette, A., Smith, J. J., Hammerschmidt, R., Sundin, G. W. (2008). Identification and Onion Pathogenicity of Burkholderia cepacia Complex Isolates from the Onion Rhizosphere and Onion Field Soil. Appl. Environ. Microbiol. 74: 3121-3129 [Abstract] [Full Text]  
• Aubert, D. F., Flannagan, R. S., Valvano, M. A. (2008). A Novel Sensor Kinase-Response Regulator Hybrid Controls Biofilm Formation and Type VI Secretion System Activity in Burkholderia cenocepacia. Infect. Immun. 76: 1979-1991 [Abstract] [Full Text]  
• Lynch, K. H., Dennis, J. J. (2008). Development of a Species-Specific fur Gene-Based Method for Identification of the Burkholderia cepacia Complex. J. Clin. Microbiol. 46: 447-455 [Abstract] [Full Text]  
• Perez-Martinez, I., Zhao, Y., Murillo, J., Sundin, G. W., Ramos, C. (2008). Global Genomic Analysis of Pseudomonas savastanoi pv. savastanoi Plasmids. J. Bacteriol. 190: 625-635 [Abstract] [Full Text]  
• Soto, M. J., Sanjuan, J., Olivares, J. (2006). Rhizobia and plant-pathogenic bacteria: common infection weapons.. Microbiology 152: 3167-3174 [Abstract] [Full Text]  
• Chain, P. S. G., Denef, V. J., Konstantinidis, K. T., Vergez, L. M., Agullo, L., Reyes, V. L., Hauser, L., Cordova, M., Gomez, L., Gonzalez, M., Land, M., Lao, V., Larimer, F., LiPuma, J. J., Mahenthiralingam, E., Malfatti, S. A., Marx, C. J., Parnell, J. J., Ramette, A., Richardson, P., Seeger, M., Smith, D., Spilker, T., Sul, W. J., Tsoi, T. V., Ulrich, L. E., Zhulin, I. B., Tiedje, J. M. (2006). Inaugural Article: Burkholderia xenovorans LB400 harbors a multi-replicon, 9.73-Mbp genome shaped for versatility. Proc. Natl. Acad. Sci. USA 103: 15280-15287 [Abstract] [Full Text]  
• Bernier, S. P., Sokol, P. A. (2005). Use of Suppression-Subtractive Hybridization To Identify Genes in the Burkholderia cepacia Complex That Are Unique to Burkholderia cenocepacia. J. Bacteriol. 187: 5278-5291 [Abstract] [Full Text]  
• Payne, G. W., Vandamme, P., Morgan, S. H., LiPuma, J. J., Coenye, T., Weightman, A. J., Jones, T. H., Mahenthiralingam, E. (2005). Development of a recA Gene-Based Identification Approach for the Entire Burkholderia Genus. Appl. Environ. Microbiol. 71: 3917-3927 [Abstract] [Full Text]  
• Zhao, Y., Ma, Z., Sundin, G. W. (2005). Comparative Genomic Analysis of the pPT23A Plasmid Family of Pseudomonas syringae. J. Bacteriol. 187: 2113-2126 [Abstract] [Full Text]