Application of RAPD and ISSR markers tools for commercial monovarietal Tunisian extra virgin olive oils (EVOO) authenticity and traceability

The Mediterranean basin is one of the world’s most important regions for olive oil production. The validation of the authenticity of olive oils has become a major instrument to guarantee the consumer’s protection and producer’s. The use of DNA-based methods extracted from olive oil and molecular markers could be useful to distinguish cultivars and oils. In order to backtrace the traceability of Tunisian olive oil, RAPD and ISSR molecular markers techniques were used to set up and to evaluate their feasibility to study the authenticity of five commercial Tunisian olive oils from the most abundant Tunisian olive cultivars. Five different methods of DNA extraction from monovarietal Tunisian olive oil were compared. Furthermore, the amplified products using RAPD and ISSR methods were used to evaluate the reproducibility and the level of polymorphism. Dendrograms were performed using unweighted pair group mathematical average (UPGMA) that allowed group formation according to the commercial olive oil brand. The Busconi and CTAB-Hexane-Chloroform extraction methods gave a satisfactory result in terms of total DNA extraction yield. Our results indicate that the ISSR method was the most suitable molecular-based technique for fingerprinting and assessing relationship among commercial Tunisian olive oils. This study demonstrates that olive oil from the five most predominant olive cultivars in Tunisia can be identified unequivocal by using RAPD–ISSR-based DNA profiling. Therefore, these techniques are useful and cost-effective to demonstrate the authenticity and traceability of commercial Tunisian olive oil.