Comparative study on the target sequences of thaumatin-like protein (TLP) and internal transcribed spacer (ITS) in the detection of corn component in edible oil by ladder-shape melting temperature isothermal amplification (LMTIA)

Abstract

Single copy thaumatin-like protein (TLP) genes and multiple copy internal transcribed spacer (ITS) genes from the nucleus of corn were selected as targets, designed and screened primers. The impact of target sequence selection on ladder-shape melting temperature isothermal amplification (LMTIA) detection of corn components in edible oil from aspects such as specificity, sensitivity, and stability were studied. The results showed that the LMTIA system targeting TLP has an optimal reaction temperature of 58 °C and can detect a minimum of 100 pg/μL of corn DNA, and the LMTIA system established with ITS as the target has higher sensitivity, with an optimal temperature of 59 °C, and can detect corn DNA as low as 1 pg/μL. Both systems have good specificity, stable reactions, and no false positive results were observed. Conclusion: ITS is more suitable as a target sequence for LMTIA detection of corn components in edible oil.