Genetic diversity in chestnuts of Kashmir valley Nucleic acids extraction from mangroves as woody plants needs lots of practical experience. In the present study, three different methods and the RNeasy plant mini kit were used to extract nucleic acids from mangrove plant. Modified CTAB method provided high integrity and concentration of DNA and RNA, respectively from roots and leaves. This method was successful in extraction of RNA from roots but failed for leaves of mangrove. The CTAB with β-mercaptoethanol increases RNA concentration while it decreases the purity of RNA. High yield of RNA extracted from mangrove leaves was obtained by modifying the SDS method. However, the integrity of RNA decreased. When polyvinylpyrrolidone was used to inhibit polyphenol oxidase activity, the yield and integrity of RNA had improved significantly. Therefore, the objective of this study was to isolate and identify the different genes involved in the adaptation of mangrove plants to different kind of stresses. Two-month old seedlings of the Rhizophora apiculata were exposed to 450 mM NaCl for 24 hours under hydroponic culture. Then, the expression of dihydrolipoamide dehydrogenase (DLDH) gene was studied using reverse transcriptase-PCR and real-time qRT-PCR. Keywords: Mangrove, nucleic acids extraction, RNA integrity, RNA extraction, modified methods INTRODUCTION Extraction of nucleic acids especially RNA from woody plants containing high polysaccharides and polyphenol is quite challenging task. Since, these components have been released during cell disruption. The mangrove plant is a woody plant (Rubio-Pina and Zapata-Perez, 2011) which contains large amounts of polysaccharides and polyphenols. Mangrove plants comprise of 16 families and 22 genera (Kathiresan and Bingham, 2001) and the Rhizophora apiculata is one of the “true mangrove” among 149 species of the Rhizophoraceae family (APG II, 2003) which contributes to make pure sands. The vast humid and sub- tropical marine shorelines are usually covered with mangrove plants. Mangrove plants have adapted to biotic and abiotic stresses which accrued in a wide range of tidal and wetland areas during different cycles of development (Hibino et al., 2001). Due to the increasing population growth in recent years in most parts of the world, the need for a sustainable farming system is being felt more than ever. Stable farming can be achieved either by increasing agricultural products or by producing cereal and higher plants that are resistant to a wide spectrum of biotic or abiotic stresses. Though different resistant genes have been identified and isolated from different plants, it is still not sufficient to thoroughly support the need for stable farming products. Hence, continued identification of different plants as the source of tolerance to a wide range of stresses is indispensable and plays a vital role in the attainment of a sustainable farming system. Isolation and identification of different resistance genes from different plants may also play an important role in developmental plant products. Hence, exploration of plants with high levels of adaptation is the first and most important step. The mangrove plant is a tropical/sub-tropical plant which is subjected to diverse environmental factors, such as salinity (Jayaraman et al., 2008; Ashraf, 2009; Rubio-Pina and Zapata-Perez, 2011), temperature, drought, and moisture, and has adapted to these different stresses to survive (Hibino et al., 2001) through expression of different genes at different ages and parts of the plant. Hence, the mangrove is a valuable source of genes related to resistance and tolerance and must be studied rigorously. Extracting high quality RNA is the most significant factor in constructing cDNA. Moreover, in the absence of intact RNA, the determination of gene expression seems to be impossible. Phenolic compounds and polysaccharides in mangrove Pak. J. Agri. Sci., Vol. 50(4), 529-536; 2013 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 http://www.pakjas.com.pk EXTRACTION OF TOTAL RNA FROM MANGROVE PLANTS TO IDENTIFY DIFFERENT GENES INVOLVED IN ITS ADAPTABILITY TO THE VARIETY OF STRESSES Mahbod Sahebi 1 , Mohamed M Hanafi 1,2,* , Siti Nor Akmar Abdullah 1 , Naghmeh Nejat 1 , Mohd Y. Rafii 3 and Parisa Azizi 3 1 Laboratory of Plantations Crops, Institute of Tropical Agriculture; 2 Department of Land Management, Faculty of Agriculture; Laboratory of Food Crops, Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia * Corresponding author’s e.mail: mmhanafi@agri.upm.edu.my