Transcription profiling analysis of the PecS regulon of Erwinia chrysanthemi 3937

ABSTRACT: Pathogenicity of the phytopathogenic enterobacterium Erwinia chrysanthemi, the causative agent of soft rot disease in many plants, is a complex process involving several factors whose production is subject to temporal regulation during infection. After penetrating into its host plant, E. chrysanthemi resides latently in the plant intercellular spaces without provoking any symptoms, and disease occurs only when the environmental conditions are favourable for massive bacterial multiplication and production of plant cell wall degrading enzymes. PecS is a transcriptional regulator of the MarR family that represses production of plant cell wall degrading enzymes. Here, we used microarray analysis to define the PecS regulon and demonstrated that PecS exerts wide-ranging effects on gene expression in E. chrysanthemi. However, the major effects of PecS are largely confined to specific genes that could be linked to pathogenicity and to a group of genes concerned with evading host defences. Among the identified targets are the genes encoding plant cell wall degrading enzymes, secretion systems, the genes involved in flagella synthesis, in biosurfactant synthesis, in oxidative stress response as well as genes encoding toxin-like virulence factors such as NipE and Hemolysin-coregulated proteins. Electromobility shift assays and DNAse I footprinting demonstrated that PecS directly interacts with the regulatory regions of five new targets, ahpC, rhlA, nipE, virK, avrL, that define three different functional classes of genes: oxidative stress response genes (ahpC), biosurfactant synthesis gene (rhlA), genes encoding exported proteins related to other plant associated bacteria proteins (nipE, virK, avrL). Based on this work, we propose a pivotal role of PecS in the switch from a saprophytic to a parasitic lifestyle.

ORGANISM(S): Erwinia chrysanthemi

SUBMITTER: Sylvie Reverchon 

PROVIDER: E-TABM-428 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress