Abstract
Abstract The most effective barriers preventing the collection of pure DNA from plant samples is the presence of the secondary products. Most available DNA extraction protocols were prepared to eliminate this obstruction. As a first step, Edwards’ buffer was used to isolate DNA from the leaves of tomato (Lycopersicon esculentum Mill.), which is known to contain more secondary metabolites especially polyphenol, comparing to Arabidopsis (Arabidopsis thaliana L.). This protocol has been intensively and successfully used in Arabidopsis but not for tomatoes. Results indicated that the collected DNA; without cold centrifugation, from Arabidopsis appeared as normal white jelly pellets with high purity ratio (1.93±0.072), while the DNA pellets from tomato samples showed dark color and with less purity (1.73±0.048). This difference in DNA purity was highly significant. Also, there was significant difference in DNA concentration between the two plant species; 316.38±38.0 ng/μl for Arabidopsis and 71±38.78 ng/μl for tomato. These results indicate that Edwards’ buffer method works well with Arabidopsis but not necessarily with Tomato unless some modifications are applied to the protocol. That is to eliminate secondary products from samples, with keeping its advantages as a very simple, safe, and not time-consuming way to extract genomic DNA suitable for PCR and some other tests needed in plant molecular biology. Key words: Arabidopsis, tomato, Edward’s buffer, DNA, polyphenol