ABSTRACT
The secondary metabolism in plants contributes to proper functioning against insects, pests, as well as nonbiological conditions such as high radiation or temperature. This part of the metabolism is controlled by the expression of genes associated with external signals that affect the development of the plant, generating secondary metabolites, which have been of interest due to their beneficial properties for human health caused by their antioxidant activity. Phenolic compounds are the secondary metabolites with the greatest abundance in plants. These have gained attention due to their antioxidant potential, as well as their protective functions to UV rays, diseases and pests, as well as a characteristic and attractive coloration in plants. Flavonoids are considered part of the main antioxidant-capable compounds in plants; they are synthesized primarily in chloroplasts or cytoplasm through the route of phenylpropanoids and have a wide range of functions in plants. One of the coloring pigments found in colored corns is anthocyanin, which are glycosides responsible for the red, violet, blue, and purple pigmentation seen in flowers, fruits, leaves, and other plant tissues, they can confer added value on products for human consumption. In yellow or orange corns, a concentration of carotenoids is observed, which have activities of great importance to human health, becoming part of Provitamin 272A from the carotenes, and an excellent option for the biofortification of crops. Fifty-nine native corn breeds are distributed In Mexico. In 2011, these breeds had reported 9136 records for native corns (also named “Exotic”), of which 7189 are sheltered in different national institutions or stored in cold rooms. Mexico is considered the center of origin of many corn breeds, which include Chapalote, Palomero Toluquefio, Arrocillo Amarillo, among others. These breeds come directly from the Teocintle, considered the wild ancestor of maize, dating from 8700 years ago. Because of the mutations that maize has undergone over the decades; its different breeds have developed methods by which they adapt and defend themselves from the environment surrounding them, not only through the use primary metabolism, but also through the secondary metabolism, which is present in conditions by both biotic and abiotic factors. Climate projections indicate that there will be greater variation in precipitation as well as high temperatures, although drought is considered to affect more than the effect of high temperatures on the metabolites found in the leaf, the combined effect of drought stress and high temperatures can damage the growth and productivity of plants, compared with the individual effect. According to data from the Agri-Food and Fisheries Information Service, nearly 77% of the area planted in Mexico is managed by rainfed systems, thus concluding that climate change could have a highly significant impact on food security for the country. The overall planet is in a critical situation for human development, from the ecological side, as well as the alimentary side. As noted above, climate change can bring a decrease in the yields of some species of high economic and social interest, scientists should be prepared to get face of the climate crisis. The genetic improvement of crops should take a turn to make a more efficient way of energy consumption, for different agricultural activities, as well as based on the selection of genotypes with mechanisms to defend against drought stress and high temperatures, among them, the formation of antioxidant enzymes, plant architecture, photosystem efficiency, the use of secondary metabolites, such as the previously mentioned anthocyanins, phenolic acids, and carotenoids could make easier the process of analysis to select genotypes with better adaptation to abiotic stresses. It is not too late.
