An efficient micro-method of DNA isolation from mature leaves of four hardwood tree species Acer, Fraxinus, Prunus and Quercus

It is difficult to purify DNA from mature tree leaves at the end of the growing season, because of their thick cell wall, and high content in polysaccharides, phenolic compounds and endonucleases. A simple, fast and efficient method for DNA purification from 100 mg fresh weight leaf samples is described here. It has been developed for extracting DNA from mature leaves of Quercus, Fraxinus Prunus and Acer. The protocol is a modified CTAB (hexadecyltrimethylammonium bromide) method including a combination of beta-mercaptoethanol, polyvinylpyrrolidone, sodium dodecyl sulfate and lithium chloride including short centrifugation runs. It is very efficient yielding up to 950 mu g DNA/g of fresh weight, even when very mature leaves are processed. The extracted DNA was used as template to characterise oaks by microsatellite analysis. Its efficiency has been compared to four commercially available kits and two other published. CTAB protocols. The protocol is also inexpensive compared to commercial kits. ((C) Inra/Elsevier, Paris.).