AEM
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
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 Saile, E.
Right arrow Articles by Koehler, T. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Saile, E.
Right arrow Articles by Koehler, T. M.
Agricola
Right arrow Articles by Saile, E.
Right arrow Articles by Koehler, T. M.
Applied and Environmental Microbiology, May 2006, p. 3168-3174, Vol. 72, No. 5
0099-2240/06/$08.00+0     doi:10.1128/AEM.72.5.3168-3174.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Bacillus anthracis Multiplication, Persistence, and Genetic Exchange in the Rhizosphere of Grass Plants

Elke Saile{dagger} and Theresa M. Koehler*

Department of Microbiology and Molecular Genetics, The University of Texas—Houston Health Science Center, Houston, Texas 77030

Received 21 October 2005/ Accepted 26 February 2006

Bacillus anthracis, the causative agent of anthrax, is known for its rapid proliferation and dissemination in mammalian hosts. In contrast, little information exists regarding the lifestyle of this important pathogen outside of the host. Considering that Bacillus species, including close relatives of B. anthracis, are saprophytic soil organisms, we investigated the capacity of B. anthracis spores to germinate in the rhizosphere and to establish populations of vegetative cells that could support horizontal gene transfer in the soil. Using a simple grass plant-soil model system, we show that B. anthracis strains germinate on and around roots, growing in characteristic long filaments. From 2 to 4 days postinoculation, approximately one-half of the B. anthracis CFU recovered from soil containing grass seedlings arose from heat-sensitive organisms, while B. anthracis CFU retrieved from soil without plants consisted of primarily heat-resistant spores. Coinoculation of the plant-soil system with spores of a fertile B. anthracis strain carrying the tetracycline resistance plasmid pBC16 and a selectable B. anthracis recipient strain resulted in transfer of pBC16 from the donor to the recipient as early as 3 days postinoculation. Our findings demonstrate that B. anthracis can survive as a saprophyte outside of the host. The data suggest that horizontal gene transfer in the rhizosphere of grass plants may play a role in the evolution of the Bacillus cereus group species.

* Corresponding author. Mailing address: Department of Microbiology and Molecular Genetics, University of Texas—Houston Medical School, 6431 Fannin St., JFB 1.765, Houston, TX 77030. Phone: (713) 500-5450. Fax: (713) 500-5499. E-mail: Theresa.M.Koehler{at}uth.tmc.edu.

{dagger} Present address: Microbial Pathogenesis and Immune Response Laboratory, Meningitis and Special Pathogens Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, MS-D01, Atlanta, GA 30333.

Applied and Environmental Microbiology, May 2006, p. 3168-3174, Vol. 72, No. 5
0099-2240/06/$08.00+0     doi:10.1128/AEM.72.5.3168-3174.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Microbiol. Mol. Biol. Rev. Eukaryot. Cell All ASM Journals

Copyright © 2006 by the American Society for Microbiology. All rights reserved.