Accurate Cultivar Authentication of Jujube Fruits Using Nano-Fluidic Genotyping of Single Nucleotide Polymorphism (SNP) Markers

Chinese jujube (Ziziphus jujuba Mill.) is an economically important fruit tree that is highly adapted to marginal crop lands and can be grown under a very broad range of climate conditions. Jujube fruits produced from several traditional cultivars in Ningxia, China have enjoyed a premium market price due to their unique flavor and quality attributes. One problem with the high-end jujube market is the adulteration of premium cultivars. The accurate identification of the genetic identity of single jujube fruits is essential for cultivar traceability and authentication. The multi-locus SNP barcoding approach offers an effective solution for cultivar authentication of jujube fruits. To identify variant SNP sequences a nanofluidic array approach was used to test the efficacy of this method with DNA extracted from the fruit pulp of eight jujube cultivars from Ningxia, China. The SNP marker profiles identified the genetic identity of each fruit unambiguously based on multilocus matching and ordination analysis. Results for repeated sampling of multiple fruits from the same tree (using independent DNA extractions) showed a high level of concordance, which demonstrated the reliability of SNP based genotyping platform. This method can handle 100 s to 1000 s of samples per day (based on the platform used). It is robust and cost-effective and has a high potential for its practical application in the jujube industry. The developed method and protocol can be readily applied for botanical authentication of other stone fruits in general.