ObjectiveDNA methylation is an important epigenetic modification that plays an essential role in plant growth and development. In this study, the chemically-induced promoter and the Arabidopsis thaliana demethylation transferase gene AtDME1 were introduced into the genome of Populus alba × P. glandulosa ‘84K’, and the expression of AtDME1 was effectively induced by 17-β-estradiol treatment. The expression characteristics of AtDME1 in transgenic poplar plants were investigated. This study laid a foundation for the establishment of poplar methylation-induced variation system and genetic improvement of poplars.

MethodThe chemically-induced promoter and AtDME1 were transformed into genome of P. alba × P. glandulosa ‘84K’ using Agrobacterium-mediated transformation. Traditional PCR and DNA sequencing were used to identify the transgenic plants in hygromycin resistant plants. The chemical inducer 17-β-estradiol was used to induce expression of AtDME1 in in vitro leaves of a transgenic clone for 0, 3, 6, 12, 24, 48, 96 and 144 hours, and the expression of AtDME1 gene was detected by quantitative real-time PCR (qRT-PCR).

ResultA total of 224 hygromycin resistant buds were obtained, among them six hygromycin resistant plants were screened. Finally, six transgenic plants were identified by molecular methods, which were named as AD-1−6. Results of qRT-PCR showed that the expression of AtDME1 reached its highest level after 3 hours treatment of 17-β-estradiol, and its expression gradually decreased after12 hour’s treatment.

ConclusionThe chemical inducer 17-β-estradiol can rapidly and efficiently induce the expression of AtDME1 gene in transgenic poplar, which lays a solid foundation for further study on the mechanism of DME1 gene in the regulation of poplar genome methylation. It lays a solid foundation for the study of the chemical expression characteristics of poplar.