Crop Biotech Update

Detection and Identification of Rice Cultivars in Wheat/Rice Bread through PCR

September 3, 2010

With the shortage of wheat due to poor climatic conditions and water supply, rice has been included as an ingredient of leavened breads. However, the identification of cereal grain sources in yeast leavened breads is tricky because of the presence of DNA of yeasts and grains. Furthermore, the DNA is disrupted during fermentation. Thus, Sumiko Nakamura and Ken'ichi Ohtsubo of Niigata University, Japan, developed wheat-specific and rice-specific primers to multiply the DNA of wheat or rice to detect the presence of rice in wheat bread, and wheat in rice bread. These cereal specific primers are important in conducting Polymerase Chain Reaction (PCR) to avoid allergic individuals from unconscious consumption of bread with cereal allergens. The scientists prepared the template DNA using the CTAB DNA isolation technique followed by extraction of the DNA using 70% ethyl alcohol.

The four PCR primers developed amplified only the DNA of the material rice without multiplication of DNA from wheat or yeast. This led to the identification of four rice cultivars (premium rice, ordinary rice, low-gluten rice, and high amylase rice) in wheat/rice blended bread sample.

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