Ozone: Changing Anthracnose (caused by Colletotrichum acutatum) Severity and Accelerating Hypersensitive Response in Pepper

The interaction effects of ozone $(O_3)$ and anthracnose (Colletotrichum acutatum) disease were examined in green fruits and seedlings of pepper (Capsicum annuum). Pre-treatment with $(O_3)$ as a factor causing predisposition to the disease prior to infection was investigated in green fruits and stems using an $(O_3)$ concentration of 150 nL/L, which is easily reached in summer in Korea. $(O_3)$ treatment increased antioxidative responses in pepper foliar tissues, and defense against anthracnose was examined in fruits and stems. Anthracnose severity on stems of the $O_3-treated$, ozone-sensitive 'Dabotop' cultivar was always lower than that on untreated plants, but the difference was not always significant (p=0.147). Significantly lower anthracnose severity was found on $O_3-treated$ green 'Dabotop' fruits as compared to untreated green fruits in three of eight replicate experiments. In contrast, hypersensitive responses in 03treated seedlings were significantly accelerated compared to those in untreated seedlings by about 7.8 h (p