A peach (Prunus persica)-specific gene, Lhcb2, used as an endogenous reference gene for qualitative and real-time quantitative PCR to detect fruit products

- The endogenous reference gene of peach, Lhcb2, was firstly selected.
- The copy number of Lhcb2 in peach genome was single.
- Detection limit of quantitative PCR was as low as 5 pg of DNA.
- Qualitative and quantitative PCR of Lhcb2 were conducted to detect the peach in food.

Among the methods used to detect food adulteration, the amplification of endogenous reference genes is particularly important. Endogenous reference genes for many different species, such as cotton, papaya, maize and others, have been reported, yet an endogenous reference gene for the peach is still lacking. In this paper, the chlorophyll a/b-binding protein (Lhcb2) gene was identified as a species-specific gene for the peach. Lhcb2 was assayed in 4 species of peaches and 8 non-peach species by both qualitative and quantitative PCR. No amplification was observed in other species. The detection limit of quantitative PCR was as low as 5 pg of DNA, equal to 9 copies, and Southern blot analysis confirmed that the Lhcb2 gene was present in a single copy in the peach genome. All of these experiments indicated that the Lhcb2 gene is a useful endogenous reference gene for the detection of peach material via both qualitative and quantitative PCR assays, even in the processed food samples such as juices containing peach.