Comparison of Defensive Enzyme Activities in the Leaves of Seven Oriental Lily Hybrids after Inoculation with Botrytis elliptica

Plant resistance characteristics are closely related to changes in the activities of self-defense enzymes after infection. Despite significant differences in the resistance of different lily ( Lilium sp.) cultivars to leaf blight ( Botrytis elliptica ), few studies of their resistance physiology exist. This study explored changes in the resistance-related enzyme activity of several lily cultivars after leaf blight inoculation. Seven oriental lily cultivars (Lilium hybrids) with obvious differences in resistance were used as experimental materials. After inoculation with B. elliptica , the activities of four defense enzymes, superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonia-lyase (PAL), and peroxidase (POD), were determined according to the light absorption values at different wavelengths after their reactions. The results showed that the activities of SOD and CAT differed between the highly resistant and highly susceptible hybrids. Before inoculation, SOD activity was relatively low in all cultivars. However, after inoculation, the SOD activity increased sharply in the resistant cultivars. In the moderately resistant cultivars, the SOD activity did not change drastically. In the susceptible cultivars, the SOD activity initially showed slight increases or decreases and then increased. CAT activity showed reactions similar to those of SOD. Some changes in PAL and POD activity occurred after inoculation, but no significant correlations were present between these trends and resistance characteristics. In addition, no significant changes in enzyme activities were found in the control plants of the seven cultivars during the testing period. Overall, the resistance of Lilium oriental hybrids to B. elliptica is related to SOD and CAT activity but does not show much of a relationship with PAL and POD activity. Studying the physiological metabolic pathways of SOD and CAT appears to be an important direction in research to elucidate resistance to B. elliptica in Lilium oriental hybrids.