Comparative analysis of five DNA isolation protocols and three drying methods for leaves samples of Nectandra megapotamica (Spreng.) Mez

Abstract

The aim of the study was to establish a DNA isolation protocol Nectandra megapotamica (Spreng.) Mez., able to obtain samples of high yield and quality for use in genomic analysis. A commercial kit and four classical methods of DNA extraction were tested, including three cetyltrimethylammonium bromide (CTAB)-based and one sodium dodecyl sulfate (SDS)-based methods. Three drying methods for leaves samples were also evaluated including drying at room temperature (RT), in an oven at 40ºC (S40), and in a microwave oven (FMO). The DNA solutions obtained from different types of leaves samples using the five protocols were assessed in terms of cost, execution time, and quality and yield of extracted DNA. The commercial kit did not extract DNA with sufficient quantity or quality for successful PCR reactions. Among the classic methods, only the protocols of Dellaporta and of Khanuja yielded DNA extractions for all three types of foliar samples that resulted in successful PCR reactions and subsequent enzyme restriction assays. Based on the evaluated variables, the most appropriate DNA extraction method for Nectandra megapotamica (Spreng.) Mez. was that of Dellaporta, regardless of the method used to dry the samples. The selected method has a relatively low cost and total execution time. Moreover, the quality and quantity of DNA extracted using this method was sufficient for DNA sequence amplification using PCR reactions and to get restriction fragments.