Abstract: [Objective] Eucommia ulmoides is a dioecious perennial woody plant with high medicinal and economic values. The utilization value was different between male and female of E. ulmoides, especially of the gutta-percha and other secondary metabolites. Also, it was difficult to identify sex by morphological or cytological methods before flowering, and the trees need more than 7 years to bloom. EST-SSR markers were used to find sex-associated ones, and expected to identify sex at early stage for improving the utilization of E. ulmoides resources.[Method] We screened primers by using DNA samples of 6 male and 6 female plants from 7 different regions, and the primers ware designed based on the SSRs locus flanking sequences of dioecious transcriptome library of E. ulmoides. We obtained gender different products by PCR which has been cloned and analyzed, then another 12 male and 12 female plants were used to test reliability of the gender markers.[Result] The result showed that only one pair of primers(EST-Eu059) out of 140 pairs of EST-SSR primers displayed different bands between male and female, a common band was about 160 bp(named as Eu-f160 and Eu-m160) for both male and female plants, with an extra band of 120 bp approximately(named as EuMSM) in all males. Sequence analysis indicated that Eu-f160 and Eu-m160 were 156 bp, with the repeat unit (GT)₆, and only 1 base was different, that was, the third G base in the female repeat unit became A; and EuMSM was 112 bp without (GT)₆. By Blastn comparison, EuMSM was not homologous with the sequences in the GenBank database. We confirmed that there was a male-specific band in all male plants.[Conclusion] We selected one pair of primers EST-Eu059 that can be used to identify male and female plants of E. ulmoides, which had a specific band EuMSM in male plants. This marker can be used to identify sex of E. ulmoides quickly and reliably at an early stage.

Key words: Eucommia ulmoides, EST-SSR, male-specific sequence, sex identification