Ethanol pretreatment increases DNA yields from dried tree foliage

Abstract

DNA isolated from silica gel dried leaves are frequently low in yield and quality due to accumulation of phenolic compounds, which interfere with the quality of the isolated DNA. In this work, we attempted to improve DNA quality of silica gel dried leaves. Hence, leaves of Picea schrenkiana were collected and soaked in different concentrations of ethanol (70, 80, 90, 95, 100%) for different periods of time (24, 36, 48 h). Thereafter, leaves were dried and stored for about 8 days in a cellophane bag containing silica gel. Afterwards, DNA was isolated from the leaf samples using Cetyltrimethyl-Ammoniumbromide (CTAB) protocol. The result shows that soaking P. schrenkiana leaves in ethanol before preserving them in silica gel improved the DNA yield. This result indicates that, soaking leaf samples in ethanol prior to silica gel desiccation can increase DNA yield. Ethanol may have acted in disrupting the foliage cell wall, deactivating DNases in the foliage, and extracting certain carbohydrates from the foliage prior to the drying process, and thus, increase the DNA yield. © The Author(s) 2010.