Plant Genomic DNA Isolation-the Past and the Present, a Review

Successful isolation of a good quality of plant genomic DNA in sufficient quantity is a necessary prerequisite for its downstream applications, that are aimed to examine and analyze the molecular intricacies of the plant kingdom. The quantity and quality of isolated genomic DNA often determines the accuracy and robustness of results derived from many DNA based applications. The choice of the method adopted for DNA isolation depends on a large number of factors like the amount, nature and age of the starting plant tissue, the infrastructure available in terms of laboratory facilities, ready availability of required laboratory chemicals, time at hand and the downstream applications of the obtained DNA. A large number of modifications have been suggested to optimize DNA isolation from a particular plant species or tissue. There cannot be a universal protocol for DNA isolation across all plant species or tissues owing to the highly heterogeneous nature of plant cells. Hence, efforts need to be made to carry out suitable variations in the extraction method, so as to develop a protocol which is best suited to a particular plant species or tissue or application. So far, a large number of DNA isolation protocols from plants have been published, but there is no comprehensive report on suitability of these methods over each other and the different modifications which have been attempted to optimize the yield and quality of DNA. Many review papers have described various DNA isolation protocols and their underlying principles, that have been adopted in order to optimize DNA isolation from different plant species and tissues (Varma et al., 2007; Tan and Yiap 2009; Kumari et al., 2012). However, there is no comprehensive study which gives details of modifications at different steps of the plant genomic DNA isolation protocol, that have been attempted by researchers to overcome the specie and tissue specific limitations. This review gives a detailed account of the steps involved in genomic DNA isolation from various plant species and tissues and how each of these steps have been modified to overcome and eliminate the problem of contaminants in the extracted DNA so as to obtain a good quality of DNA amenable to downstream molecular biology applications.