The challenge of relating gene expression to the virulence of Salmonella enterica serovar Typhimurium

The first decade of transcriptomic studies of Salmonella enterica serovar Typhimurium focused upon gene expression in vitro, and during the infection of mammalian cells. The published regulons and stimulons show that the three Type Three Secretion Systems of S. Typhimurium respond to a diverse range of environmental conditions, and are controlled by a hierarchy of regulatory proteins. The integration of in vitro generated transcriptomic data with global gene expression of S. Typhimurium during infection is beginning to yield valuable information. The coordinated regulation of Salmonella gene expression is a key process for survival, adaptation and virulence capacities of the pathogen.

► Overview of 50 S. Typhimurium transcriptomic studies dating from 2003 to 2010. ► Wealth of in vitro transcriptomics but few datasets from S. Typhimurium infection. ► Genes that are highly expressed during infection often play a direct role in virulence. ► Lack of published studies of Salmonella gene expression during food processing. ► Understanding global gene expression datasets continues to be a challenge.