Comparative Study of DNA Preservation Under Various Conditions on Local Egyptian Cowpea Germplasm

 

Abd El-Hadi I. H. Sayed, Hossam F.A. El-Shaer, Abeer El-Halwagi, Ehab M.B. Mahdy*

This study were to study the impact of storage conditions on DNA quality in different materials, the integrity and quality of stored DNA; as well as determining the best way to store of DNA extracts in some Cowpea plants collected from different sites in Egypt. Ten germplasm representing Vigna radiata and V. unguiculata, procured from local regions by National Gene Bank (NGB), Agricultural Research Centre (ARC), Giza, Egypt. The DNA from each treatment was stored in different buffers for at least a year at LN, –20°C, –80°C and room temperature (RT) without special control of temperature or humidity. In order to simulate and evaluate the long-term storage samples subjected to high temperature over a period of time by extrapolation could correspond to 100 years at 25°C. These experiments were conducted on the samples of ten samples of Vigna at 65°C for one day in hot-plate. The obtained results, the protectant trehalose were the highest value of DNA concentration (43.6±1.1 ng/µL) at room temperature, following by PVA scored 43.5±1.0 ng/ µL at RT and TE buffer showed 43.5±0.7 ng/µL at -20°C, for stored DNA.
The average mean of PVA and trehalose were 43.5±1.1 ng/ µL more than TE-buffer. For stored tissue, the high mean (43.5±0.8 ng/µL) value of DNA concentration scored with the silica-gel and herbarium specimens, respectively. DNA samples of ten samples under study were also subjected to PCR analysis using SSR to determine whether the DNA was degraded. While no degradation was observed for DNA stored under different conditions, special in dry conditions (≤ 5% humidity). To assess its effects on DNA stability during storage at different conditions under controlled humidity. It was very interesting to note that DNA samples stored in the presence or absence of protectant additives exhibited no detectable degradation, whereas in the absent of, DNA was degraded and appeared as a smear on an agarose gel.