Development of SSR markers for a Tibetan medicinal plant, Lancea tibetica (Phrymaceae), based on RAD sequencing

Premise of the study: Lancea tibetica (Phrymaceae), a Tibetan medicinal plant, is endemic to the Qinghai-Tibet Plateau. The over-exploitation of wild L. tibetica has led to the destruction of many populations. To enhance protection and management, biological research, especially population genetic studies, should be carried out on L. tibetica. Simple sequence repeat (SSR) markers of L. tibetica were developed to analyze population diversity.

Methods and results: Four thousand four hundred and forty-one SSR loci were identified for L. tibetica based on restriction-site associated DNA (RAD) sequencing on the Illumina HiSeq platform. One hundred SSR loci were arbitrarily selected for primer design, and 38 of them were successfully amplified. These markers were tested on 56 individuals from three populations of L. tibetica, and 10 markers displayed polymorphisms. The total number of alleles per locus ranged from three to eight, and observed and expected heterozygosities ranged from 0.200 to 1.000 and 0.683 to 0.879, respectively. We tested for cross-amplification of these 10 markers in the related species L. hirsuta and found that nine could be successfully amplified.

Conclusions: The SSR markers characterized here are the first to be developed and tested in L. tibetica. They will be useful for future population genetic studies on L. tibetica and closely related species.