Assessment of genetic variation and evolutionary dynamics in saffron through matK and rbcL barcodes

Abstract

The saffron plant (Crocus sativus L.), renowned for its culinary and medicinal properties, faces genetic challenges due to its vegetative propagation and restricted cultivation regions. This study investigates saffron's genetic variation at the nucleotide level using DNA barcoding with two loci (rbcL and matK) across sixteen accessions from diverse geographic regions. Amplicon analysis revealed that the rbcL locus (720 bp) is longer than matK (613 bp) and exhibits greater variability. Sequence analysis identified 27 polymorphic sites in rbcL and 15 in matK, with rbcL showing higher insertion-deletion diversity (9.883 vs. 5.358) and more mutations (29 vs. 17). These differences resulted in 13 haplotypes for rbcL and 11 for matK, yielding a high haplotype diversity (HD = 0.95). Notably, the TH3 accession displayed distinct genetic traits, as evidenced by phylogenetic trees and PCA clustering. A positive correlation between genetic distance and altitude (Kendall’s r = 0.244, p = 0.00032) was observed for matK. Two-dimensional DNA barcoding provided effective visualisation of genetic markers. This study highlights the utility of rbcL and matK barcodes for exploring saffron’s genetic diversity and evolutionary dynamics, providing critical insights into germplasm management and conservation efforts.