Soutenance de thèse en visioconférence : Shiny MARTIS BADIADKA

Computational modeling of virulence genes expression: a study of gene regulation during plant pathogenesis

Doctorante : Shiny MARTIS BADIADKA

Laboratoire INSA : MAP

Ecole doctorale :  EDA 341 : Évolution, Écosystème, Microbiologie, Modélisation

Plant pathogens are a major threat to food security all around the world. Virulence genes enable the pathogens to disease the host and pose threats. We study and computationally model the expression of virulence in pathogens. The pel genes, a major virulence factors in pectinolytic bacteria which infect plants and cause soft rot disease. The Pel enzymes released by the pathogen results in the maceration of tissue in crop and facilitate pathogenesis. We model the pel genes in our model organism Dickeya dadantii. We study pelD/E genes which encode proteins with similar enzymatic activities, but also share the same set of transcriptional regulators, thus raising the question of the benefit of this duplication and the specific role of these two genes. We model their expression with respect KdgR repressor and CRP activator. We develop a quantitative dynamic kinetic model of this process, that reproduces the observed behavior of the two genes and explains their specific role in the infection. The regulatory part of the model is based on experimental values, and fitted kinetic parameters are subjected to systematic evaluation. The model is robust and has multiple applications for studying the pathogenesis of pectinolytic bacteria. In addition, we explore the instance of carbon catabolite repression observed during the regulation of virulence genes Dickeya dadantii.