Elimination of oxalate contamination in RNA isolation from<Emphasis Type="Italic">Rumex obtusifolius</Emphasis>

Many plant RNA isolation techniques aim to prevent contamination by means of secondary phenolics, carbohydrates, RNase, and other chemicals. However, when applied in our laboratory to the isolation of RNA fromRumex obtusifolius, these protocols failed to produce good quality RNA. A major problem was contamination of the RNA samples with the secondary metabolite oxalate. The relative quantities of guanidine isothiocyanate extraction buffer to plant tissue used in the protocol had significant effects on oxalate contamination. An increase in extraction buffer, from 1.5 mL in the original method to 15 mL per 200–300 mg of tissue in our protocol, removed the oxalate from the RNA. This RNA was of a good quality and was suitable for molecular biology applications.