Oltmanns Heiko, Kloos Dorothee U, Briess Waltraud, Pflugmacher Maike, Stahl Dietmar J, Hehl Reinhard
PLANTA Angewandte Pflanzengenetik und Biotechnologie, GmbH, Grimsehlstrasse 31, 37555 Einbeck, Germany.
Planta. 2006 Aug;224(3):485-95. doi: 10.1007/s00425-006-0230-3. Epub 2006 Feb 16.
The storage root (taproot) of sugar beet (Beta vulgaris L.) originates from hypocotyl and primary root and contains many different tissues such as central xylem, primary and secondary cambium, secondary xylem and phloem, and parenchyma. It was the aim of this work to characterize the promoters of three taproot-expressed genes with respect to their tissue specificity. To investigate this, promoters for the genes Tlp, His1-r, and Mll were cloned from sugar beet, linked to reporter genes and transformed into sugar beet and tobacco. Reporter gene expression analysis in transgenic sugar beet plants revealed that all three promoters are active in the storage root. Expression in storage root tissues is either restricted to the vascular zone (Tlp, His1-r) or is observed in the whole organ (Mll). The Mll gene is highly organ specific throughout different developmental stages of the sugar beet. In tobacco, the Tlp and Mll promoters drive reporter gene expression preferentially in hypocotyl and roots. The properties of the Mll promoter may be advantageous for the modification of sucrose metabolism in storage roots.
甜菜（Beta vulgaris L.）的贮藏根（主根）起源于下胚轴和初生根，包含许多不同的组织，如中央木质部、初生和次生形成层、次生木质部和韧皮部以及薄壁组织。这项工作的目的是表征三个贮藏根表达基因的启动子的组织特异性。为了对此进行研究，从甜菜中克隆了Tlp、His1-r和Mll基因的启动子，将其与报告基因连接，并转化到甜菜和烟草中。转基因甜菜植株中的报告基因表达分析表明，所有这三个启动子在贮藏根中均有活性。在贮藏根组织中的表达要么局限于维管区（Tlp、His1-r），要么在整个器官中观察到（Mll）。在甜菜的不同发育阶段，Mll基因具有高度的器官特异性。在烟草中，Tlp和Mll启动子优先驱动报告基因在下胚轴和根中表达。Mll启动子的特性可能有利于贮藏根中蔗糖代谢的修饰。
