Second, we showed that the antioxidant genes encoding vitamin B6 (i.e., PDX, PLR), CAT and, GST of R. solani AG3 and potato are differentially induced and transcriptionally regulated at the site of infection (i.e., necrotic tissues, and in the surrounding areas) during R. solani AG3-potato sprout interaction (pathosystem I). The gene discussed is CAT; the disease is infection.