Analysis of the Correlation between Fungicide Resistance and Catalase and Superoxide Dismutase Activities in Monilinia laxa

Monilinia laxa is one of the most important fungal pathogens commonly present in sweet cherries, sour cherries, apricots, plums, almonds, and peaches in Türkiye, which is one of the world’s leading producers of cherries and apricots. Superoxide dismutase (SOD) and catalase (CAT) are key antioxidant enzymes that help aerobic organisms manage oxidative stress by detoxifying reactive oxygen species. This study was conducted to determine the correlation between the resistance of M. laxa isolates to the fungicides cyprodinil, thiophanate-methyl, and captan and the activities of the fungal antioxidant enzymes SOD and CAT. The results indicated that the application of cyprodinil (10 µg/mL), thiophanate-methyl (10 µg/mL), and captan (100 µg/mL) did not cause statistically significant changes in the specific activities of SOD and CAT enzymes in M. laxa. Despite the significant variation in specific activities of the enzymes among the three M. laxa isolates, a strong positive correlation was found between specific activities of the SOD and CAT. To the best of our knowledge, this is the first study to explore the relationship between the resistance of M. laxa to the fungicides cyprodinil, thiophanate-methyl, and captan and the activities of the antioxidant enzymes SOD and CAT, as reported in the existing literature.