Figure 1.

Schematic representation of the mutagenesis cassette cloned in the donor plasmid prpfF-kan for homologous recombination and replacement of the target rpfF gene with the kanamycin resistance gene (kan) in the genome of X. fastidiosa strain De Donno. (a) rpfF gene structure on the X. fastidiosa gene region, indicating the two (rpfF upstream and rpfF downstream) amplified regions of the gene; (b) structure of the prpfF-kan donor plasmid structure; and (c) structure of the X. fastidiosa genome after homologous recombination. PCR primers RpfF_F/RpfF_R, Kan_F/Kan_R, RpfFMut_F/RpfFMut_R, used to verify the effectiveness of recombination, are indicated by orange, green, and blue arrows, respectively.