DNA Extraction and Isolation:
The protocol reported by Doyle & Doyle CTAB method (1987) was employed with following modification: Take
50-60mg of fresh leaves of okra and grinded with liquid nitrogen, after thawing ground the sample in mortar with a
preheated CTAB extraction buffer (1.5ml/sample) with 0.2% 2-betamercaptoehanol (Table 1). Incubate at 650C for
1 hour, after that add 1.5μL of RNase and incubate at 370C for 20 min. Centrifuge at 12000 rpm for 10 min to pellet
the debris then add equal volume of Chloroform: Isoamyl alcohol (24:1 v/v) to the supernatant and gently vortex for
10 min and centrifuge 13000 rpm for 10 min. Transfer the supernatant into 0.7 volume of ice-cold isopropanol and
0.15 volume ammonium acetate to precipitate DNA at -200C for 30 min.Washing done twice by adding 500μL of
70% chilled ethanol to remove ions and then from absolute ethanol. Centrifuge at 13000 rpm for 1 min to pellet the
DNA, then air dry and re-suspend in 50μL of TE buffer.