In Turkey and in the world in general, the seed sector is developing rapidly. The ever-increasing nutritional demand of the world's population makes it inevitable to develop new cultivars with high quality and yield. This has led to a rapid increase in the number of cultivars in plant species that have economic value. Lentil (Lens culinaris Medik.) contains high levels of vegetable protein and is commonly found on our tables. For this reason, lentil is one of the most prevalently consumed legume species that is constantly being developed. Due to the fact that Turkey is the gene center of lentils and has important cultivation areas, there are many different cultivars of lentils in the market. The yield and quality potentials of all lentil cultivars differ from each other. Therefore, it is extremely important to identify the cultivars to minimize cheating/confusions in both the use of cultivars suitable for soil/climatic conditions that are demanded in production and in trade while choosing parents in breeding activities.
All food products must comply with the description provided by the manufacturers or processors with reference to the origin of the ingredients, as well as the identity of the species, breeds or cultivars used. Substitution of plant cultivars of high commercial value with a cheaper, lower-quality one is a common fraud committed against consumers and producers. Such fraud causes confusion in the market, disaffection towards genuine products and price fluctuation. DNA-based methods are more reliable and used for routine analyses to maintain food safety and quality (Martins-Lopes et al. 2013). Additionally, DNA-based methods offer tools to ensure food authenticity and traceability of primary products entering food chains in terms of both fresh and processed food (Böhme et al. 2019)
SSR markers are highly polymorphic markers that have been useful for identifying species and cultivars of both raw materials and processed food. The high level of polymorphism is due to different numbers of repeats in the microsatellite loci that are distributed to the entire genome. Therefore, SSRs are amenable to high throughput genotyping and also a useful tool for paternity analysis, construction of high-density genome maps, marker-assisted selection and for establishing genetic and evolutionary relationships (Kalia et al. 2011).
DNA barcoding is another increasingly used molecular technique that analyzes one or few standardized loci for identifying species or cultivars. The mitochondrial gene Cytochrome c oxidase subunit 1 (cox1 or COI) was proposed as a DNA barcode for identification of animal species by Hebert et al. 2003. However, mitochondrial DNA barcode candidates are useless for plants because plant mitochondrial sequences evolve slowly (Mower et al. 2007). Therefore, the attention of researchers is focused on plastid genomes. Plastid genes (rpoC1, rpoB, matK, rbcL), plastid intergenic spacers (atpF–atpH, trnH–psbA and psbK–psbI) and the internal transcribed spacer region (ITS) have been initially proposed as candidate barcoding loci (Kress et al. 2005; Chase et al. 2007; Fazekas et al. 2008). The CBOL Plant Working Group (2009), recommended a two-locus combination of rbcL + matK as the core barcode for land plants. Accordingly, it has been reported that the rbcL, matK and trnH - psbA regions have a high level of distinctive characteristics between species when used together (Kress et al. 2007; Group et al. 2009; Hollingsworth et al. 2011). In comparison to other plant barcode loci, rbcL has a low mutation frequency. However, it is informative for the intra-species level. matK is one of the most rapidly evolving plastid regions and shows high levels of discrimination among angiosperm species (Hilu and Liang 1997; Fazekas et al. 2008). The presence of the highly conserved coding sequences of trnH-psbA makes the design of universal primers feasible with a single primer pair likely to amplify nearly all angiosperms (Shaw et al. 2005; Shaw et al. 2007). trnH-psbA exhibits the most sequence divergence and has high rates of insertion/deletion (Kress and Erickson 2007).
In this study, we identified registered lentil cultivars in Turkey with two commonly recommended plant DNA barcoding loci (matK and trnH-psbA) and 15 SSR markers, for ensuring the traceability of lentil cultivars in the market.