Mara Schultz's Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Rostock University in the year 2020.
Title: The role of the small protein HliR1 in Synechocystis sp. PCC 6803 during high light stress
Schultz characterized the physiological role of the recently annotated small protein HliR1 and detected its participation in the high light stress response in Synechocystis sp. PCC 6803.
The small protein HliR1 was newly annotated by Baumgartner et al. (BMC Microbiol 28:2016) in the genome of Synechocystis, where hlir1 is located in front of the gene for superoxide dismutase (SOD). SOD is involved in the removal of reactive oxygen species in the cell, which occur in particular in the case of strong light stress.
To analyze the physiological role of HliR1 in Synechocystis, several mutants were available in which the protein-coding or RNA-coding part of hliR1 was deleted. Furthermore, a strain in which HliR1 was expressed in the mutant was examined. Schultz characterized these strains phenotypically, biochemically and molecular biologically with regard to growth under different conditions. In addition, I aimed to detect interactions of HliR1 with other proteins.
The physiological investigations showed that HliR1 plays an important role during high light stress. The mutant with the protein-coding sequence deleted could not grow in strong light, while the expression of hliR1 in this mutant abolished the phenotype. However, neither changes in the SOD activity nor an HliR1-SOD interaction could be detected that would have explained this phenotype. Investigation of protein-protein interactions suggests that HliR1 may interact with various proteins involved in building and repairing photosystem II. This finding suggests that HliR1 may play a role in the repair of photosystem II under high light stress.
Mara Schultz conducted this work at the Institute for life sciences in the working group of Prof. Dr. Martin Hagemann.