Of the catalytic PP2A subunits, PP2A-C5, and to some extent also PP2A-C2 transcript abundance increases in response to various plant pathogens, ozone fumigation that mimics pathogen infection by promoting extracellular ROS burst (Vainonen and Kangasjärvi, 2015) and various pathogenic elicitors, whereas abiotic stresses appear to decrease the expression of the catalytic PP2A subunits. This evidence concerns the gene PTPA and infection.