Molecular Mechanisms of Persistence of Mutualistic.pdfVIP

Molecular Mechanisms of Persistence of Mutualistic Bacteria Photorhabdus in the Entomopathogenic Nematode Host Ruisheng An, Parwinder S. Grewal* Department of Entomology, The Ohio State University, Wooster, Ohio, United States of America Abstract Symbioses between microbes and animals are ubiquitous, yet little is known about the intricate mechanisms maintaining such associations. In an emerging mutualistic model system, insect-pathogenic bacteria Photorhabdus and their insect- parasitic nematode partner Heterorhabditis, we found that the bacteria undergo major transcriptional reshaping in the nematode intestine. Besides general starvation mechanisms, the bacteria induce cellular acidification to slow down growth, switch to pentose phosphate pathway to overcome oxidative stress and nutrition limitation, and shed motility but develop biofilm to persist in the nematode intestine until being released into the insect hemolymph. These findings demonstrate how the symbiotic bacteria reduce their nutritional dependence on the enduring nematode partner to ensure successful transmission of the couple to the next insect host. Citation: An R, Grewal PS (2010) Molecular Mechanisms of Persistence of Mutualistic Bacteria Photorhabdus in the Entomopathogenic Nematode Host. PLoS ONE 5(10): e13154. doi:10.1371/journal.pone.0013154 Editor: Vladimir N. Uversky, Indiana University, United States of America Received July 19, 2010; Accepted September 10, 2010; Published October 5, 2010 Copyright:  2010 An, Grewal. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This project was supported by a competitive grant from the Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio. The funders had no role in study design, data collection and analysis, decision to p