This Article Full Text Full Text (PDF) Other Versions of this Article: AEM.00356-07v1 73/17/5516    most recent 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 Google Scholar Google Scholar Articles by Stoddard, L. I. Articles by Marston, M. F. Search for Related Content PubMed PubMed Citation Articles by Stoddard, L. I. Articles by Marston, M. F. Agricola Articles by Stoddard, L. I. Articles by Marston, M. F.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, September 2007, p. 5516-5522, Vol. 73, No. 17
0099-2240/07/$08.00+0     doi:10.1128/AEM.00356-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Selection and Characterization of Cyanophage Resistance in Marine Synechococcus Strains

Lauren I. Stoddard,^1, Jennifer B. H. Martiny,^2, and Marcia F. Marston^1*

Department of Biology, Roger Williams University, Bristol, Rhode Island 02809,¹ Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02861²

Received 13 February 2007/ Accepted 3 July 2007

Marine viruses are an important component of the microbial food web, influencing microbial diversity and contributing to bacterial mortality rates. Resistance to cooccurring cyanophages has been reported for natural communities of Synechococcus spp.; however, little is known about the nature of this resistance. This study examined the patterns of infectivity among cyanophage isolates and unicellular marine cyanobacteria (Synechococcus spp.). We selected for phage-resistant Synechococcus mutants, examined the mechanisms of phage resistance, and determined the extent of cross-resistance to other phages. Four strains of Synechococcus spp. (WH7803, WH8018, WH8012, and WH8101) and 32 previously isolated cyanomyophages were used to select for phage resistance. Phage-resistant Synechococcus mutants were recovered from 50 of the 101 susceptible phage-host pairs, and 23 of these strains were further characterized. Adsorption kinetic assays indicate that resistance is likely due to changes in host receptor sites that limit viral attachment. Our results also suggest that receptor mutations conferring this resistance are diverse. Nevertheless, selection for resistance to one phage frequently resulted in cross-resistance to other phages. On average, phage-resistant Synechococcus strains became resistant to eight other cyanophages; however, there was no significant correlation between the genetic similarity of the phages (based on g20 sequences) and cross-resistance. Likewise, host Synechococcus DNA-dependent RNA polymerase (rpoC1) genotypes could not be used to predict sensitivities to phages. The potential for the rapid evolution of multiple phage resistance may influence the population dynamics and diversity of both Synechococcus and cyanophages in marine waters.

Published ahead of print on 13 July 2007.

Present address: Department of Pathology and Laboratory Medicine, Brown University, Providence, RI 02903.

Present address: Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697.