Dr Siphathele Sibanda
Microbiology and Plant Pathology
In my Postdoctoral research, I am continuing with the investigation of quorum sensing in Pantoea ananatis, a Gammaproteobacteria that belongs to the family Enterobacteriaceae. This bacterial species is represented by pathogenic and non-pathogenic strains depending on the host. Pathogenic strains of P. ananatis cause diseases in economically important crops including staple food crops, such as corn, rice, sorghum, cash crops, for example, honeydew melons, pineapples, onions and plants such as the Eucalyptus. Completion of the genome of P. ananatis revealed three quorum sensing systems in P. ananatis, two LuxI/R systems (the EanI/R and the RhlI/R) and the LuxS. My PhD focused on characterisation of LuxI/R quorum sensing systems in P. ananatis. In addition, the quorum sensing regulon of the EanI/R system was identified by RNA sequencing. This study has broadened our understanding of quorum sensing gene regulation in this bacterium. Functional characterisation of those genes regulated by quorum sensing could help in the formulation of control measures for this plant pathogen.