Development and characterization of 20 novel EST-SSR markers for Pteroceltis tatarinowii, a relict tree in China.

PREMISE: Pteroceltis tatarinowii (Ulmaceae), the only species of the genus Pteroceltis, is an endangered tree in China. Here, novel expressed sequence tag-simple sequence repeat (EST-SSR) markers were developed to illuminate its genetic diversity for conservation and assisted breeding. METHODS AND RESULTS: Based on Illumina transcriptome data from P. tatarinowii, a total of 70 EST-SSR markers were initially designed and tested. Forty-eight of 70 loci (68.6%) were successfully amplified, of which 20 were polymorphic. The number of alleles per locus ranged from two to six, and the levels of observed and expected heterozygosity ranged from 0.018 to 0.781 and from 0.023 to 0.702, respectively. Additionally, cross-amplification was successful for 17 loci in two related species, Ulmus gaussenii and U. chenmoui. CONCLUSIONS: These new EST-SSR markers are valuable transcriptomic resources for P. tatarinowii and will facilitate population genetics and molecular breeding of this species and its relatives in Ulmaceae.