The objective of a new study is to assess the ability of the DNA barcoding approach to identify different taxonomic groups from two flowering plant collections:
- the most relevant commercial taxa (nursery production) and
- Mediterranean plants with ornamental attitude (new emerging species).
"Core markers", rbcL and matK, were adopted the identification step of 100 taxa belonging 2 to 20 families. A third marker, the intergenic spacer trnH-psbA, was also tested, on 74 taxa, when the core markers were not able to discriminate well the analysed germplasm.
DNA barcode fragments were recovered for all the total taxa investigated (100%). The rbcL showed the best performances: the greatest amplification success, the best sequencing performance both in terms of the number of sequences obtained and in terms of quality of the sequences obtained. Despite having recorded greater amplification difficulties, according to numerous other studies, matK has shown a good success in sequencing and quality of the obtained sequences (de Vere et al. 2012), unlike what is indicated in some protocols that suggests for this region the need for further primers to be adopted for the sequencing phase (Hollingsworth et. al 2011).
Results showed that sixty-one taxa overall (61%) were totally resolved at specific or subspecific level, by at least one of the three markers. The matK and rbcL locus respectively resolved 44% and 35% of the taxa. The core markers in multilocus approach led to the discrimination of a total of 49% taxa. The trnH-psbA was able to discriminate 52% of taxa analysed and resulting determinant in the discrimination of 14 taxa. Four families, including the major number of taxa (Arecaeae, Fabaceae, Euphorbiaceae, Asteraceae), were evaluated in terms of genetic distance (K2P% value).
This work highlighted the potential of the barcoding approach for a rapid identification of plant species in order to solve taxonomic disputes and support commercial traceability of floreal products.