DNA barcoding of Ziziphus jujuba Mill. in Iran using chloroplast genes (rbcL and matK)

Jujube (Ziziphus jujuba Mill.) is one of the most important medicinal plants belong to the Rhamnaceae family. It is important in the pharmaceutical industry. So far, many molecular tools have been used to study genealogy and population structure and genetic relationships between jujube and wild jujube. Since 2000, much research has focused on genetic relationships between different varieties of jujube or wild jujube using molecular markers. Genetic diversity of different species of Z. jujuba in Iran in 2007 and in 2006 classified the sex of 19 species by simultaneous analysis of morphological traits and molecular methods. The main purpose of this study is DNA Barcoding of different ecotypes of Z. jujuba in South Khorasan, Iran using two chloroplast genes (rbcL and matK).

The 25 numbers of the ecotypes of this species from 6 different provinces of Iran were planted in South Khorasan, were assessed. Two close relatives of the same family (Sangoisorba sp., Rosa sp.) were also used as external groups.Purification (protein and polysaccharide refining) was performed using the manual method. The gel was then stained with ethidium bromide and the DNA quality was estimated using the agarose gel electrophoresis results. The chloroplast genes from the DNA extracted were amplified using the PCR technique. All sequences obtained from forward and reverse reading in this study to produce the final sequence using appropriate software were assembled.

The DNA barcode of each species was performed for fast, accurate and automatic identification of the species and all the sequences obtained from this study were sent to the NCBI (National Center for Biotechnology Information) and submitted. The results show that there is the greatest genetic distance between jujube ecotypes and two samples from the out-group and no significant genetic diversity between different jujube ecotypes and morphological differences are due to ecological conditions. However, the analysis of gene combination data provided more informational insights than the separate analysis of sequence data. According to the results, the highest diversity was observed in the ecotypes of South Khorasan.

The results of pairwise distance and haplotype networks showed the most variety among different ecotypes belonged to the different areas of South Khorasan province. Also, Soth Khorasan can be considered as the origin of this species in Iran. Previous studies have fully confirmed the results of this study. However, given the economic importance of jujube plants in the world, Iran and especially South Khorasan, it is recommended to use more samples and more genes, especially nuclear genes, to study more closely the genetic similarities and differences of these ecotypes.