The expression of three genes encoding the reactive oxygen species (ROS) scavenging enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD) and catalase (CAT), induced during the systemic infection of kiwifruit leaves with PSA, were chosen to further validate the reliability of the selected RGs for the normalization of RT-qPCR data. This evidence concerns the gene SOD1 and infection.