The most common approaches to obtain single base resolution are based on ‘bisulfite treatment’ of the genomic DNA sample. By bisulfite treatment cytosine is converted to uracil, while 5mC remains unchanged. In MSP bisulfite treated DNA is amplified by PCR using primer pairs spanning the CpG site of interest. Herein, a primer pair is either designed for methylated-specific DNA or unmethylatedspecific DNA. Due to the conversion of C into U, mismatches are introduced preventing or enabling efficient PCR amplification, depending on the chosen primer pair. Here we demonstrated that the selectivity of a KlenTaq DNA polymerase can be altered by substituting a polar amino acid residue that interacts with the backbone of the primer strand. We successfully identified mutants with increased mismatch selectivity for each examined amino acid position. These findings emphasise the power of combining an initial rational design approach with the rigorous use of a screening based combinatorial enzyme design. However, by gene shuffling the best performing single mutants, we were not able to further improve the desired properties, as combinations of advantageous single point mutations resulted in decreased protein stability and activity. The most promising mutant was thoroughly characterized. We selected the mutant R660V for investigation and found that the enzyme has increased mismatch selectivity and could be used even in multiplexing assays using genomic DNA templates demonstrating its suitability for SNP detection. Additionally, KlenTaq R660V is able to perform ASA from DNA in the presence of whole blood with no previous DNA purification. We could also show that KlenTaq R660V is suitable for application in MSP to detect the methylation status at a single site. To investigate the impact of the single mutation on overall DNA polymerase selectivity we determined the error rate and spectra of KlenTaq R660V and found it to be somewhat increased compared to the wild-type enzyme. Disease resistance in plants depends on the ability of the host to recognize pathogens and initiate defense mechanisms that limit infection. A basal type of immunity in plants is conferred by the recognition of conserved microorganism-associated molecular patterns by specific pattern-recognition receptors that protect hosts against non-specialized pathogens. Receptor-Like Kinase RLK known as resistance proteins able to recognize the presence of pathogen effector molecules and to activate effector-triggered immunity. This response is typically associated with programmed cell death of the infected cells and the production of antimicrobial molecules. Modulation of hormone pathways is required to restrict pathogen invasion, re-allocate resources, control cell death and modify plant architecture. In addition, systemic-acquired resistance, which immunizes against subsequent infections, could also occur.