In the literature homologous calcium-dependent protein kinases (CDPK also CPK) CPK21 and CPK23 from Arabidopsis thaliana share similar function in the phytohormone abscisic acid-dependent stress response. This data suggest an at least partial functional redundancy. The generation of a double mutant line by crossing is prevented through the adjacent localization of both genes coding for CPK21 and CPK23 on chromosome 4. Therefore, in this thesis a cpk21cpk23 double mutant was generated via targeted genome editing. The resulting double mutant and respective single mutants were compared and assessed in germination rate, root length, biomass and rosette diameter. These phenotypical analyses demonstrated a reduced root length of 5-day old seedlings in cpk21 and cpk23 mutants, which was not enhanced in the double mutant. To investigate a potential contribution of a different isoform, in this master thesis a triple mutant including cpk21, cpk23 was generated for the first time via CRISPR/Cas9.

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Fabian-Philipp Sylvester conducted this work at the department biochemistry of plants in the group of Prof. Dr. Tina Romeis