Revealing the function of the plastidial serine biosynthesis pathway in Arabidopsis thaliana

• Applicant: Privatdozent Dr. Stephan Krüger
• Subject Area: Plant Biochemistry and Biophysics
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 219232255

Plants have several possibilities for the synthesis of serine. The most prominent pathway is the photorespiration pathway, which is thought to be the major route for serine synthesis in photosynthetic cells. In non-photosynthetic cells serine might be synthesized by the phosphoserine pathway (PS-pathway). However, the function of this pathway in plants is far from being understood. Our preliminary results indicate that some enzymes of the PS-pathway are involved in the synthesis of tryptophan, whereas others might be involved in amino acid degradation during senescence. Furthermore, we have strong indication that the PS-pathway is essential for proper embryo development and have important functions at later stages of plant development. Our work aim at unraveling the role of this pathway in plants, especially to discover the non-redundant function of the different isoenzymes for the 3-phosphoglycerate dehydrogenase (PGHD) and phosphoserine-aminotransferase (PSAT). Additionally, the PGDH enzyme catalyses the rate limiting step within the PS-pathway and is known to be feedback regulated by serine in other organism like Escherichia coli. Our work will further aim on the role of this feedback regulation in plants and therefore, the kinetic properties of the PGDHs will be determined and serine insensitive variants of the PGDH enzyme will be generated.

• DFG Programme: Research Grants