Identificação de marcadores microssatélites correlacionados à atividade antioxidante em Lactuca sativa L.

Abstract

Lettuce (Lactuca sativa L.) can be considered the main leafy vegetable consumed in Brazil. It is present in the daily menu of the Brazilian, preferably in the form of salad and its consumption presents great nutritional importance. Greenery is an abundant source of nutrients. It is rich in minerals such as calcium and iron; vitamins, such as A, B1, B2 and C, in addition to other phytochemical compounds. Among the phytochemicals present in lettuce, we highlight carotenoids (provitamin A) and anthocyanins. These substances have antioxidant action and act to prevent aging and control the oxidative stress related to the action of free radicals. The present work had the objective of studying the genetic divergence between 12 lettuce cultivars (Gabriela, Luiza, Model, Optima, Raider Plus, Red Star, Salad Bowl, Silvana, Sophia, Thaís, Verônica and Darkland) in 10 pairs of microsatellite primers and to associate these results to the evaluation of the antioxidant activity of each cultivar performed by the DPPH • and ABTS + • free radical capture methods, reduction of the Phosphomolybdenum complex and quantification of the phenolic compounds by means of the Folin-Ciocalteau reagent. The methodology consisted of evaluating the phenotypic characteristics of the cultivars, by verifying the color of each cultivar and quantifying the antioxidant activity; and genotyping of samples from 10 pairs of SSR primers. The antioxidant activity values obtained by all methods were correlated with the staining of the cultivars through Pearson's Correlation and Mantel's Test. In order to evaluate the dissimilarity between the cultivars, a distance matrix of Gower was generated. Microsatellite loci were compared with the levels of antioxidant activity obtained for each cultivar using the ABTS + •, DPPH •, phosphomolybdenum complex reduction and total phenol content; as well as the coloring of the plants. The results showed that the cultivar Red Star (dark purple coloring) showed higher% AA in most of the tests performed. The loci KSL-37, KSL-137, KSL-245 showed a positive and statistically significant correlation with the "dark purple" cultivars, Red Star and Gabriela. SML-022 was positively related to the results obtained by the phosphomolybdenum complex reduction test. Thus, these markers have been shown to be good indicators of antioxidant activity, and may be used in future studies that seek to associate this characteristic with lettuce cultivars.