BM 2013, Vol.4, No.4, 19-22 http://bm.sophiapublisher.com 19 Research Report Open Access Extraction of High-quality Intact DNA from Okra Leaves Despite Their High Content of Mucilaginous Acidic Polysaccharides Nisar Ahmed 1 , Sehar Nawaz 1 , Ahsan Iqbal 1 , Muhammad Mubin 1 , Aisha Butt 1 , David A Lightfoot 2 , Masahiko Maekawa 3 1 Centre of Agricultural Biochemistry and Biotechnology (CABB), University of Agriculture, Faisalabad, 38000, Pakistan 2 Department of Plant, Soil and Agricultural Systems, Mailcode 441205 Lincoln Drive, Carbondale IL62901, USA 3 Institute of Plant Science and Resources, Okayama University, 2-20-1, Chuo, Kurashiki, 710-0046, Japan Corresponding author email: drmiannisar@yahoo.com Bioscience Methods 2013, Vol.4, No.4 doi: 10.5376/bm.2013.04.0004 Received: 29 Apr., 2013 Accepted: 28 May, 2013 Published: 04 Jun., 2013 Copyright: © 2013 Ahmed et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article as: Ahmed et al., 2013, Extraction of high-quality intact DNA from okra leaves despite their high content of mucilaginous acidic polysaccharides, Bioscience Methods, Vol.4, No.4 19-22 (doi: 10.5376/bm.2013.04.0004) Abstract The presence of mucilaginous acidic polysaccharides in okra leaves interferes with the extraction of high-quality intact DNA for later restriction digestion and PCR amplification. We have developed a simple, efficient and reliable protocol to extract high-quality, intact DNA from the highly mucilaginous leaves of okra. The isolated DNA was free of contaminating agents like polysaccharides, protein and polyphenols and (A/260: A/280) ratio of 1.6~2.1 indicate minimal presence of other contaminating metabolites. The extracted DNA was digested with restriction enzyme AvaII and analyzed by PCR using random amplified polymorphic DNA primers. The extraction protocol is simple and does not require liquid nitrogen. The yield and quality of the resulting DNA are satisfactory, and the protocol can be scaled-up. Keywords Okra, DNA extraction, Mucilaginous acidic polysaccharides, SDS 1 Background Okra (Abelmoschus esculentus Moench) is an edible hibiscus of the Malvaceae family. It is often cross-poll- inated and is a popular vegetable crop in the tropics. Okra is very useful against genito-urinary disorders, spermatorrhoea and chronic dysentery (Nandkarni, 1927). It has been reported to use as medicine in curing ulcers and relief from hemorrhoids (Adams, 1975). Previous studies have reported that 100 gm of okra endow with calcium (20%), iron (15%) and vitamin C (50%) of human dietary requirements (Grubben, 1977). Leaves of okra have high mucilaginous acidic polysa- ccharides content forming pectin and its main component is polygalacturonic acid associated with minerals, which presents a major problem during the purification of okra DNA. When cells are lysed nucleic acids come into contact with these polysaccrides (Loomis, 1974). In the oxidised form these polyphenols bind covalently and irreversibly to proteins and nucleic acids (Guilletmaut and Marechal-Drouard 1992) resulting in a brown gelatinous material that reduces the yield and purity of the extracted DNA (Porebski et al., 1997; Aljanabi et al., 1999) and prevents it from redissolving completely. Furthermore, DNA which dissolves even in the presence of these polysaccharides inhibits the activity of different restriction enzymes (Sahu et al., 2012), PCR, or in vitro labeling. The availability of high quality intact genomic DNA is a precondition for almost every molecular genetic analysis of crops. But when a plant tissue is rich in polysaccharide contaminants, Isolation of good quality DNA for PCR, gene mapping, diversity assessments and other molecular analyses is challenging, secondary metabolites and polyphenoles. Protocols for the isolation of DNA from tissues with high levels of polysaccharides and polyphenols have been reported (Dellaporta et al., 1983; Bernatzky and Taksley, 1986; Lodhi et al., 1994; Wang et al., 1996; Wang et al., 2011; Kim et al., 1997; Li et al., 2002; Geuna et al., 2004) but these did not give satisfactory results with okra. Due to problems with DNA isolation, there have been few studies at the molecular level in okra. Appropriate