PhD project position paid by the ANR project Sincerely (CDD Dcotoral 36 mois, H/F)

The Institute for Integrative Biology of the Cell (I2BC) is an UMR CNRS - CEA - Paris-Saclay University with more than 700 people aiming to understand the fundamental mechanisms of life at the cellular and molecular levels. The student will work in the department of Microbiology in the team “Plant-bacteria interactions” which is composed by 3DR, 1CR, 1 MdC, 1IR, 4 PhD students and 1 AI.

During the nitrogen fixing symbiosis with leguminous plants of the species Medicago sativa, the bacterium Sinorhizobium meliloti differentiates into an enlarged and polyploid cell (bacteroid) , capable of fixing nitrogen but incapable of reinitiating a normal cell cycle. This bacterial terminal differentiation is highly connected to the inactivation of the master regulator of cell cycle, CtrA, which controls DNA replication and cell division in S. meliloti. The main regulation of CtrA is by phosphorylation through a cascade (involving the kinase CckA, the phosphotransferase ChpT and the scaffold DivL), which has been studied in closely related bacteria. The objective of this PhD project is to understand the role of CckA, ChpT and DivL in the Medicago symbiont in the context of cell cycle and symbiotic differentiation.
This PhD project is organized in three multidisciplinary tasks based on bacterial molecular genetics, molecular biology, biochemistry of the signaling cascade and bacterial and plant cell biology. Based on the knowledge accumulated in the team, the PhD candidate will explore the possibility to ameliorate the bacterial differentiation during symbiosis.
The ideal candidate may have experience in the domain of molecular microbiology. Also knowledge in molecular genetics, molecular biology and genetic engineering of bacteria are highly recommended. As a bonus the candidate may have experience in the study of the bacterial cell cycle regulation, in particular related to regulatory networks. Finally the interest in plant biology and the experience working with plants will be highly welcomed.