Pi genes, such as Pib (Wang et al. 1999), Pi25 (Shang et al. 2009), Pi-ta (Bryan et al. 2000), Pi9 (Qu et al. 2006), Pi2 and Piz-t (Zhou et al. 2006), Pi5 (Lee et al. 2009) and Pi54 (Rai et al. 2011) are often constitutively expressed in rice plants, and more highly expressed upon infection by the fungus. This evidence concerns the gene SERPINA1 and infection.