Saffron is a monomorphic species as revealed by RAPD, ISSR and microsatellite analyses

BACKGROUND: Saffron (Crocus sativus) is considered the world's most expensive spice. Used mainly as a colorant for foodstuffs, it is highly appreciated for its aromatic and flavouring properties. Since no molecular markers for this species have been found in the literature, the objective of this study was to determine whether phenotypical differences found in C. sativus were supported by molecular analyses. FINDINGS: Thirty primers from Operon Technologies were used in random amplified polymorphic DNA (RAPD) analysis, forty eight primers were screened using intersimple sequence repeats (ISSR) method and fifteen primers derived from a microsatellites library flanking sequences with repeat motifs were assayed in forty three isolates of C. sativus from eleven different countries and a C. kotschyanus isolate was used as outgroup. No polymorphic bands were detected in any of the accessions combining the different approaches used in this study. CONCLUSION: According to our findings, all accessions appear identical clones, not only because morphological characters but also at a molecular level. These data strongly suggested that C. sativus is a monomorphic species. Thus, genome sequencing is needed to find molecular markers for saffron.