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The Combination of Quantitative PCR and Western Blot Detecting CP4‐EPSPS Component in Roundup Ready Soy Plant Tissues and Commercial Soy‐Related Foodstuffs
Author(s) -
Xiao Xiao,
Wu Honghong,
Zhou Xinghu,
Xu Sheng,
He Jian,
Shen Wenbiao,
Zhou Guanghong,
Huang Ming
Publication year - 2012
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2012.02718.x
Subject(s) - western blot , soy protein , biology , genetically modified organism , plant protein , nucleic acid , food science , gene , biochemistry
With the widespread use of Roundup Ready soy (event 40–3‐2) (RRS), the comprehensive detection of genetically modified component in foodstuffs is of significant interest, but few protein‐based approaches have been found useful in processed foods. In this report, the combination of quantitative PCR (qPCR) and western blot was used to detect cp4‐epsps gene and its protein product in different RRS plant tissues and commercial soy‐containing foodstuffs. The foods included those of plant origin produced by different processing procedures and also some products containing both meat and plant protein concentrates. The validity of the 2 methods was confirmed first. We also showed that the CP4‐EPSPS protein existed in different RRS plant tissues. In certain cases, the results from the western blot and the qPCR were not consistent. To be specific, at least 2 degraded fragments of CP4‐EPSPS protein (35.5 and 24.6 kDa) were observed. For dried bean curd crust and deep‐fried bean curd, a degraded protein fragment with the size of 24.6 kDa appeared, while cp4‐epsps gene could not be traced by qPCR. In contrast, we found a signal of cp4‐epsps DNA in 3 foodstuffs, including soy‐containing ham cutlet product, meat ball, and sausage by qPCR, while CP4‐EPSPS protein could not be detected by western blot in such samples. Our study therefore concluded that the combination of DNA‐ and protein‐based methods would compensate each other, thus resulting in a more comprehensive detection from nucleic acid and protein levels. Practical Application: The combination of quantitative PCR (qPCR) and western blot was used to detect cp4‐epsps gene and its protein product in different Roundup Ready soy (event 40–3‐2) plant tissues and commercial soy‐containing foodstuffs. The foods included those of plant origin produced by different processing procedures and also some products containing a combination of both meat and plant protein concentrates. This study indicated that the combination of DNA‐ and protein‐based methods would supplement each other for genetically modified detection from nucleic acid and protein levels. Accordingly, qPCR and western blot could be used in CP4‐EPSPS detection in a wide variety of soy‐related foodstuffs.