Influence of growth conditions on an antioxidative system in two bell pepper genotypes differing in susceptibility to phytopathogen bacteria Xanthomonas euvesicatoria

Abstract

With changing environmental conditions food production is becoming increasingly challenging. The production of cultivars resistant to various abiotic and/or biotic stresses may be one of the solutions. In this study, we analyzed the response of the antioxidant system in two different bell pepper genotypes, 26 susceptible and 19 tolerant, to Xanthomonas euvesicatoria when grown in the open field, greenhouse, free and isolated. The activity of four antioxidant enzymes, superoxide dismutase, glutathione reductase, catalase, and total peroxidase was highest in susceptible genotype 26 grown in isolation in the greenhouse. Both genotypes activate ascorbate peroxidase when grown in the field, suggesting that this enzyme is first in the line of defense under these growing conditions. In addition, susceptible genotype 26 had the highest concentration of ascorbic acid as a non-enzymatic defense when grown in the field. However, the carotenoid content of 26 was the lowest in the field, and the ratio of carotenoids to total chlorophyll was lowest in the field for both genotypes. In general, the susceptible genotype 26 activated the antioxidant and other defense systems more frequently than the tolerant genotype 19. Genotype 19 responded to different growth conditions with additional physiological adaptation through chlorophyll and carotenoid concentration correlated with growth location. This suggests that crossbreeding experiments to obtain genotype 19 allow the acquisition of tolerance to some abiotic stressors in addition to tolerance to the biotic stressor.