ROLE OF THE BACTERIAL CELL WALL GLYCO CONJUGATES IN ELICITATION OR SUPPRESSION OF EUKARYOTIC INNATE IMMUNITY
The innate immune response plays an important role in eliciting host defence against microbial infections by the early recognition between pathogens' structures arranged on the bacterial surface, called MAMPs; and their specific receptors in the host cells. Within this frame, my PhD project is focused on studying the role of bacterial glycoconjugates in the activation of immune response in plant cells. Glyco conjugates represent a very heterogeneous group of biomolecules which includes lipopolysaccharides (LPS) peptidoglycan (PGN) glycolipids and glycoproteins. In Gram negative bacteria, the majority of membrane glycoconjugates is constituted by lipopolysaccharides (LPS) amphiphilic macromolecules consisting of three different portions: a lipophilic domain called Lipid A, a hetero oligosaccharide denominated Core, a hydrophilic hetero polysaccharide called O polysaccharide chain or O chain. They are pivotal in mediating many processes of host bacteria interaction like adhesion, recognition, pathogenesis, symbiosis. In order to understand the molecular basis of bacterium host interaction, it is important to elucidate the structure of LPS and to identify how bacterium modifies the LPS in response to different environments and stimuli. It has been already demonstrated that a correct structure of LPS is required to establish a disease (pathogens) or to produce a beneficial outcome (symbiont) in host microbe interaction. In particular, part of my PhD thesis is focused on bacteria involved in legume symbiotic nitrogen fixation by Rhizobiaceae, widespread in nature and able to fix nitrogen and symbiotic with plant roots. Rhizobiaceae, considered as biofertilizers, in agricultural system would decrease the need of chemical fertilizers, which are not only cost effective but also may create environmental problems.