Random Amplification Polymorphic DNA- Polymerase Chain Reaction
RAPD-PCR stands for Random Amplification Polymorphic DNA- Polymerase Chain Reaction (Ruiz et. al. 2000). A random section of subject DNA is amplified into concentrated PCR products. These products are paired with general primers that align themselves at random sections within the DNA template (Ortiz-Herrera et. al. 2004). The PCR products, along with a standard, are then feed through an agarose gel that will physically separate the products based upon their molecular weight. The results obtained from the agarose gel are then reported in a band-like pattern. This gives qualitative results. The RAPD-PCR technique is employed to distinguish between strains or subspecies of microorganisms (Tofalo et. al. 2009).
Application in Wine Microbiology:
The RAPD-PCR technique has been used in the differentiation of isolated yeast strains. In one particular study, non-Saccharomyces yeast, such as Candida apicola, Candida zemplinina, and Zygosaccharomyces bailii as well asSaccharomyces species were found to withstand high sugar-concentrated must during the fermentation process (Tofalo et. al. 2009). Other methods were employed to identify the particular genera of the yeast as well as the species; however, RAPD-PCR was the only technique capable of identifying the subspecies or particular strains of the yeast found within the must (Tofalo et. al. 2009). In another study, RAPD-PCR was used to help identify the best possible Oenococcus oeni strain from a group, consisting of ten possible strains for the completion of a malolactic fermentation. RAPD-PCR was used at the end of the fermentation process to assess the most reliable and dominant strains (Guzzon et. al. 2009). RAPD-PCR allows for the selection of strains with desirable attributes and, therefore, a higher quality wine.
- Guzzon, R., E. Poznanski, L. Conterno, P. Vagnoli, S. Krieger-Weber, and A. Cavazza. 2009. Selection of a New Highly Resistant Strain for Malolactic Fermentation Under Difficult Conditions. South African Journal of Enology and Viticulture 30: 133-141.
- Ortiz-Herrera, M., A. Geronimo-Gallegos, F. Cuevas-Schacht, L. Perez-Fernandez, and R. Coria-Jimenez. 2004.RAPD-PCR Characterization of Pseudomonas aeruginosa Strains obtained from cystic fibrosis patients. Salud Publica Mex 46: 149-157.
- Ruiz, R., D. Vacek, P. Parker, L. Wendel, U. Schaffner, R. Sobhian, and R. Richard. 2000. Using Randomly Amplified Polymorphic DNA Polymerase Chain Reaction (RAPD-PCR) to Match Natural Enemies to Their Host Plant. Proceedings of the X International Symposium on Biological Control of Weeds. pp. 289-293.
- Tofalo, R., C. Chaves-Lopez, F. Di Fabio, M. Schirone, G. Felis, S. Torriani, A. Paparella, and G. Suzzi. 2009. Molecular Identification and Osmotolerant Profile of Wine Yeasts that Ferment a High Sugar Grape Must. International Journal of Food Microbiology 130: 179-187.