Dendrobium SSR markers play a good role in genetic diversity and phylogenetic analysis of Orchidaceae species

In recent years, the development of DNA marker systems has advanced our genetic diversity and phylogenetic understanding of plant genetic resources, but simple sequence repeat (SSR) markers were still relatively limited in the Orchidaceae family. In the present study, a set of 320 Dendrobium SSR markers were applied to test their transferability and polymorphism in this large plant family, and 109 of them showed high transferability (an average of 24.71%) and polymorphism (an average of 85.91%) across 44 species of 15 Orchidaceae genera. Ten SSR loci were randomly selected for DNA sequencing, and sequence alignment analysis revealed nucleotide variation of the SSR motifs and repeat lengths among Orchidaceae taxa. Those polymorphic SSR markers were further used for phylogeny analysis and the results showed a complex genetic architecture among genera but a relatively uniform structure in the same genus. These 109 cross-taxon transferable microsatellite markers enrich the available resource of molecular markers, which would facilitate further evolution and genetic diversity studies, germplasm appraisal and molecular breeding of Orchidaceae species.