Fire blight is one of the most damaging bacterial diseases in apple and pear orchards. All cultivated Malus x domestica species are highly to moderately susceptible. Wild apple species such as Malus x robusta 5 are known to have high levels of resistance. This resistance could be mapped to one genetic locus. In this locus on linkage group three, one candidate resistance gene, FB_MR5, was identified coding for a protein with the structure CC-NBS-LRR. FB_MR5 was engineered into susceptible Gala plants with the aim to demonstrate its functionality.