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 Google Scholar
Google Scholar
Right arrow Articles by Yao, J.
Right arrow Articles by Allen, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yao, J.
Right arrow Articles by Allen, C.

 Previous Article  |  Next Article 

Journal of Bacteriology, September 2007, p. 6415-6424, Vol. 189, No. 17
0021-9193/07/$08.00+0     doi:10.1128/JB.00398-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

The Plant Pathogen Ralstonia solanacearum Needs Aerotaxis for Normal Biofilm Formation and Interactions with Its Tomato Host{triangledown}

Jian Yao{dagger} and Caitilyn Allen*

Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin 53706

Received 16 March 2007/ Accepted 20 June 2007

Ralstonia solanacearum is a soilborne pathogen that causes bacterial wilt of diverse plant species. To locate and infect host plant roots R. solanacearum needs taxis, the ability to move toward more favorable conditions. However, the specific signals that attract this pathogen were unknown. One candidate is aerotaxis, or energy taxis, which guides bacteria toward optimal intracellular energy levels. The R. solanacearum genome encodes two putative aerotaxis transducers. Cloned R. solanacearum aer1 and aer2 genes restored aerotaxis to an Escherichia coli aer mutant, demonstrating that both genes encode heterologously functional aerotaxis transducers. Site-directed mutants lacking aer1, aer2, or both aer1 and aer2 were significantly less able to move up an oxygen gradient than the wild-type parent strain; in fact, the aerotaxis of the aer mutants was indistinguishable from that of a completely nonmotile strain. Tomato plants inoculated with either the aer2 or the aer1/aer2 mutant had slightly delayed wilt disease development. Furthermore, the aer1/aer2 double mutant was significantly impaired in the ability to rapidly localize on tomato roots compared to its wild-type parent. Unexpectedly, all nonaerotactic mutants formed thicker biofilms on abiotic surfaces than the wild type. These results indicate that energy taxis contributes significantly to the ability of R. solanacearum to locate and effectively interact with its host plants.

* Corresponding author. Mailing address: Department of Plant Pathology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, WI 53706. Phone: (608) 262-9578. Fax: (608) 263-2626. E-mail: cza{at}plantpath.wisc.edu

{triangledown} Published ahead of print on 29 June 2007.

{dagger} Present address: DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824.

Journal of Bacteriology, September 2007, p. 6415-6424, Vol. 189, No. 17
0021-9193/07/$08.00+0     doi:10.1128/JB.00398-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.





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