Identification of five highly priced tuna species by quantitative real-time polymerase chain reaction

Abstract

Tunas are economically important fishery worldwide, and are often used for commercial processed production. For effective fishery management and protection of consumers′ rights, it is important to develop a molecular method to identify species in canned tuna products rapidly and reliably. Here, we have developed a duplex quantitative real-time PCR (qPCR) for identification of five highly priced tuna species (Thunnus maccoyii, Thunnus obesus, Thunnus albacares, Thunnus alalunga and Katsuwonus pelamis) from processed as well as fresh fish. After amplification and sequencing of seven genetic markers commonly used for species identification, 16S rDNA and control region (CR) of mitochondrial DNA were selected as the reference gene markers for genus Thunnus and tuna species identification, respectively. Subsequently, a 73 bp fragment of 16S rDNA and 85–99 bp fragment of CR were simultaneously amplified from each target species by qPCR. The qPCR efficiency of each reaction was calculated according to the standard curves, and the method was validated by amplification DNA extracted from single or mixed tuna specimen. The developed duplex qPCR system was applied to authenticate species of 14 commercial tuna products successfully, which demonstrated it was really a useful and academic technique to identify highly priced tuna species.

• Commercial processed tuna
• control region
• duplex quantitative real-time PCR
• species identification

Declaration of interest

This work was supported by the Key Scientific Research Project of Zhejiang Entry-exit Inspection and Quarantine Bureau (Grant No. 2014-ZKZ-010), the National High Technology Research and Development Program of China (Grant No. 2012AA092302), and the Major Science and Technology Projects of Zhejiang Province (Grant No. 2012C03009-3). Authors do not have any conflicts of interest.