The reagents for DNAsimp lysing buffer are listed in Table 2. To compare the DNA isolation efficiency of DNAsimp with the traditional CTAB protocol, we chose two tropical plants namely Maninot esculenta (cassava) and Hevea brasiliensis (rubber tree) as materials to evaluate the DNA yield and purity. Fresh leaves from cassava and rubber trees were collected with liquid nitrogen and used for total DNA extraction immediately. Four different treatments were done as follows: the traditional CTAB method (Sambrook and Russell, 2001), DNAsimp (described in ‘Materials and methods’), DNAsimp with chloroform used in precipitation of impurities, and DNAsimp with both chloroform and phenol used in precipitation of impurities.
Total DNA from cassava and rubber tree leaves were obtained by both DNAsimp and CTAB protocols. Although each of the obtained DNA was dissolved in 50 μl sterilized H2O, the 10 μl volume-equal gel electrophoresis results show obvious different concentrations of DNA from each treatment (Figure 1). Table 3 lists the purity and yield of total DNA. Samples treated with DNAsimp resulted in higher DNA concentration than the others, which was extraordinarily obvious in rubber trees (~1.7 times higher). DNA purity and yield determined by spectrophotometry measurement showed that DNA produced by the DNAsimp protocol had a somewhat high purity (A260/280≈1.8) as