Since the beginning of resistance breeding, protection of plants against pathogens has relied on specific resistance genes encoding rapid tissue death. Our work has demonstrated in different host–pathogen relationships that plants can defend themselves against pathogens by cell growth and cell division. We first demonstrated this general defence response (GDR) in plants by identifying the gds gene in pepper. Subsequently, the existence of a genetic system for tissue defence became apparent and we set the goal to analyse it. The gdr 1 + 2 genes, which operate the complete GDR system, protect plant tissues from pathogens in a direcessive homozygous state in both host and non-host relationships. The inheritance pattern of the two genes follows a 12:3:1 cleavage of the dominant epistasis. With the knowledge of the gds and gdr 1 + 2 genes, the role of tissue-preserving (GDR) and tissue-destructive (HR) pathways in disease development and their relationship was determined. The genes encoding the general defence response have a low stimulus threshold and are not tissue-destructive and pathogen-specific. They are able to fulfil the role of the plant immune system by providing a general response to various specific stresses. This broad-spectrum general defence system is the most effective in the plant kingdom.
The present study was conducted to evaluate recently developed pungent and unpungent red pepper varieties for paprika production with respect to carotenoid and tocopherol composition and content. Varieties with outstanding traits were cultivated using various methods to determine the optimal conditions for maximizing bioactive component levels. The biologically ripe fruits of these varieties were stored under ambient conditions to initiate postharvest overripening. Carotenoids and tocopherols were analyzed using recent HPLC methods. The different varieties of pungent pepper differed significantly in the levels of carotenoid groups and tocopherols. Among pungent breeds, Hetényi Triász (HET-T), CF5, and Uniring (UNIR) showed the highest levels of total carotenoids (1967.39 ± 260.35, 1642.72 ± 67.41, and 1609.07 ± 524.52 µg g−1, respectively). The highest amounts of provitamin A (187.60 ± 8.19 µg g−1) were recorded in the CF5 variety. As regards tocopherols, the highest concentration (547.09 ± 44.20 µg g−1) was recorded for CF5, with no significant differences among the studied varieties. However, the content of vitamin E was significantly higher in CF1 and CF5 than in HET-T and UNIR. Notably, under organic farming conditions, the carotenoid content in UNIR was significantly lower than in the direct-sowing and seedling-transplantation modes. Organic farming of UNIR resulted in lower levels of all carotenoid groups compared with other cultivation modes, particularly conventional seedling transplantation. The indoor cultivation of the unpungent Borbási genotype did not significantly improve the carotenoid content, particularly the total red xanthophylls. Ambient postharvest overripening led to a substantial increase, up to 3-fold, in carotenoid group content in both pungent and non-pungent genotypes. The average value for the total carotenoid content increased from 5005.7 to 8208.3 µg g−1 in unpungent varieties and from 1896.4 to 3426.8 µg g−1 in pungent varieties. For tocopherols, overripening had a slightly positive effect on total tocopherol (from 1375.3 to 1594.7 µg g−1) and esterified forms of vitamin E in pungent breeds with a significantly high increase from 532.0 to 823.7 µg g−1. In conclusion, postharvest overripening is indispensable for obtaining paprika products with an outstanding content of bioactive compounds, particularly red carotenoid diesters. Based on carotenoid content and response to overripening of red and total carotenoids, the UNIR and Borbási varieties are superior to other pungent and unpungent genotypes, respectively. The positive impact of postharvest overripening on carotenoid and tocopherol levels depended mainly on genetic factors.