Modified Method for Combined DNA and RNA Isolation From Peanut and Other Oil Seeds.

RNA isolation from plant seeds is a prerequisite for many seed specific gene expression studies and DNA is necessary in marker-assisted plant selection and other genetic studies.  We describe a modified method described by Li and Trick (2005) to isolate both RNA and DNA from the same seed tissue and have been successful with several oil seeds including peanut, soybean, and sunflower.  An additional LiCl precipitation step was added to isolate both DNA from RNA from the same seed tissue.  RNA quality was evaluated using both spectrophometric analysis and agarose gel electrophoresis.  Average ratios of 260/230 were above 2.0 indicating no contamination from phenolics and polysaccharides.  RNA was shown to be suitable for RT-PCR based on Actin primer amplification and DNA was suitable for enzyme digestion and PCR amplification.  This result shows that RNA and DNA isolated using this method can be appropriate for molecular studies in peanut.