CTAB 2X buffer

Prepare CTAB 2X buffer solution (Tris 10 mM pH8.0; EDTA 20 mM, pH 8.0; CTAB 2; NaCl 1.4 M) and preheat to 80 °C for 5 min.

Pulverize 2–3 mg of tissue using liquid nitrogen.

Mix the pulverized tissue with 700 µl of CTAB 2X in a 2 mL eppendorf tube. Mix vigorously for 20 s.

Heat to 85 °C for 2 h and mix vigorously for 20 s.

Add 750 µl of chloroform: isoamyl alcohol (24: 1) and mix vigorously for 20 s.

Centrifuge for 60 min at 12,000 g (4 °C).

Transfer the aqueous phase to a 1.5 mL eppendorf tube.

Add 400 µl of isopropyl alcohol previously cooled to − 20 °C. Mix gently for 1 min.

Centrifuge for 25 min at 10,000 g. Discard the supernatant.

Add 500 µl HPLC-grade water to the DNA pellet to dissolve the pectin (evident as a gelatinous substance). Do not mix and discard the disolved pectin with a micropipette.

Resuspend the pellet in 1 mL of ethanol (70) previously cooled to − 20 °C.

Centrifuge for 5 min at 10,000 g. Discard the supernatant.

Air-dry pellet at room temperature for 40 min.

Resuspend the pellet in 50 µl of HPLC-grade water.

Heat to 60 °C for 15 min.