Isolation of high molecular length DNA: Alfalfa, pea, rice, sorghum, soybean, and spinach

Measuring DNA damage in higher plants is important in assessing the impacts of environmental conditions, e,g,, increased UV resulting from ozone deple tion, and in testing the relationship of productivity to DNA damage and rep air. Sunlight exposure of plants produces UV-induced DNA damages measurable by treating DNA with damage-specific enzymes and dispersion of DNA molecul es in denaturing media. Such DNA must be enzyme-digestible, with few single strand breaks. DNA isolation must preclude repair, providing a "snapshot" of DNA damage. We developed a method for isolating DNA from several crop pl ants, both monocots and dicots - alfalfa (Medicago sativa L,), pea (Pisum s ativum L,), rice (Oryza sativa L,), soybean [Glycine mar (L,) Merr,], sorgh um [Sorghum bicolor (L.) Moench], and spinach (Spinacia oleraceae L,), This method is simple, readily deals with multiple samples, and avoids organic solvents. We show that pyrimidine dimers can readily be quantified in DNA p repared by this method. This method should also be useful for other experim ents requiring high molecular length, enzymatically digestible plant DNA.