Identification of Capsicum species from Colombia by DNA barcoding and high resolution melting (HRM) analysis

Abstract

DNA barcoding allows the use of molecular markers to differentiate the species of an interest group. This is especially useful when morphological characters are insufficient due to high similarity between species. The genus Capsicum contains some species that are difficult to determine by taxonomic means, in particular the annuum complex. Thus, the objective of this study was to investigate the discriminatory ability of two molecular markers in Colombian Capsicum accessions, including three wild species belonging to the Andean clade of the genus. A total of 95 Capsicum accessions, representing eight species, were genotyped by high resolution melting analysis (HRM) using the Waxy and C2_At5g04590 markers. Waxy could discriminate the Andean clade species (C. rhomboideum, C. dimorphum and C. lycianthoides), C. baccatum, C. pubescens and C. chinense, while C2_At5g04590 could discriminate C. frutescens, C. annuum var. annuum and C. annuum var. glabriusculum. Hence, a combination of the two markers could be used for discrimination of the eight species including the wild variety of C. annuum: C. annuum var. glabriusculum. Most nucleotide substitutions and indels were found in the sequences of the three Andean species, indicating that the Andean clade has a high genetic diversity compared to the other species. The incorporation of more wild species and varieties in this study allowed to correct the power of both markers to discriminate Capsicum species, besides the registration of new haplotypes.