title: A Novel Moderate Constitutive Promoter Derived from Poplar (Populus tomentosa Carrière).
abstract: A novel sequence that functions as a promoter element for moderate constitutive expression of transgenes, designated as the PtMCP promoter, was isolated from the woody perennial Populus tomentosa. The PtMCP promoter was fused to the GUS reporter gene to characterize its expression pattern in different species. In stable Arabidopsis transformants, transcripts of the GUS reporter gene could be detected by RT-PCR in the root, stem, leaf, flower and silique. Further histochemical and fluorometric GUS activity assays demonstrated that the promoter could direct transgene expression in all tissues and organs, including roots, stems, rosette leaves, cauline leaves and flowers of seedlings and maturing plants. Its constitutive expression pattern was similar to that of the CaMV35S promoter, but the level of GUS activity was significantly lower than in CaMV35S promoter::GUS plants. We also characterized the promoter through transient expression in transgenic tobacco and observed similar expression patterns. Histochemical GUS staining and quantitative analysis detected GUS activity in all tissues and organs of tobacco, including roots, stems, leaves, flower buds and flowers, but GUS activity in PtMCP promoter::GUS plants was significantly lower than in CaMV35S promoter::GUS plants. Our results suggested that the PtMCP promoter from poplar is a constitutive promoter with moderate activity and that its function is presumably conserved in different species. Therefore, the PtMCP promoter may provide a practical choice to direct moderate level constitutive expression of transgenes and could be a valuable new tool in plant genetic engineering.
authors.affiliation: National Engineering Laboratory for Tree Breeding (NDRC), Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants (MOE), the Tree and Ornamental Plant Breeding and Biotechnology Laboratory (SFA), College of Biological Science and Biotechnology, Beijing Forestry University, Qinghua Eastern Road No.35, Haidian District, Beijing 100083, China. anxinmin@bjfu.edu.cn.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Mei-Xia
authors.initials: MX
authors.lastname: Ye
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.forename: Le-Xiang
authors.initials: LX
authors.lastname: Ji
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Dong-Qing
authors.initials: DQ
authors.lastname: Cui
authors.forename: Jun-Mei
authors.initials: JM
authors.lastname: Liu
authors.forename: Xin-Min
authors.initials: XM
authors.lastname: An