Leaf conditioning of Brazilian Cerrado species for DNA microextraction

Proper conditioning of leaf tissues in collection expeditions can affect the quantity and quality of DNA in the extraction process. The aim of this work was to define a method of preserving foliar tissue suitable for obtaining DNA from Brazilian Cerrado trees. Young leaves of species (Mangaba and Baru) were collected and conditioned in five different treatments during a period of six days. Genomic DNA was obtained using two alternative versions of the cetyltrimethyl ammonium bromide (CTAB) protocol. For Mangaba, no statistical differences were verified between means of DNA values obtained with diversity arrays technology (DArT) (55 ng/μL) and CTAB (48 ng/μL) methods. It was found that the amounts of DNA obtained with the methods used differed according with the conditioning type and time (F20,60 = 1.98; p = 0.022). For Baru, the mean of DNA extracted was significantly higher (F1,60 = 42.81; p < 0.01) from the CTAB method (80 ng/μL). A significant difference (p < 0.05) was also observed between DNA means of conditioning types (F4,60 = 1.1, p = 2 × 10-4), without this being detected over time. Any preservation method tested is indicated for the selection of Mangaba and Baru foliar tissue conditioning for DNA extraction in a short period (up to six days).   Key words: Conservation, germplasm, native tree, DNA purification.