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This article is part of the supplement: IUFRO Tree Biotechnology Conference 2011: From Genomes to Integration and Delivery

Open Access Poster presentation

Cloning and Functional characterization of the promoter of a high affinity potassium transporter gene from Eucalyptus grandis

Carolina Costa1, Flávio Tetsuo Sassaki2, Juliana Bravo1 and Ivan Maia1*

Author Affiliations

1 IB - UNESP – Botucatu, Brazil

2 IB-UNESP-Botucatu, Brazil

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BMC Proceedings 2011, 5(Suppl 7):P163  doi:10.1186/1753-6561-5-S7-P163

The electronic version of this article is the complete one and can be found online at:

Published:13 September 2011

© 2011 Costa et al; licensee BioMed Central Ltd.

This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Poster presentation

The characterization of organ/tissue-specific promoters is of great interest to transgenic production. The construction of expression cassettes containing tissue-specific promoters is a viable alternative to limited transgene expression to specific organs and cell types. In this context, the purpose of this study was to functionally characterize the promoter of a Eucalyptus grandis gene encoding a high affinity potassium transporter (named EgHAK) shown to be specifically expressed in roots. For that, the 5’-flanking region of EgHAK (1,3 kb) was cloned and transcriptionally fused to the b-glucuronidase reporter gene (GUS), and then used to transform tobacco leaf discs. Histochemical analysis of GUS activity in transgenic plants showed that GUS staining was mainly detected in vascular tissues of leaf and root. To investigate the response of the studied promoter to potassium starvation, a hydroponic system was employed. In this case, enhanced GUS staining was observed in the roots of plants starved for 6 days when compared to control ones. Moreover, a weak induction of the promoter at low potassium conditions was observed using fluorimetric assays. Thus, our results indicate that, in a heterologous system, the studied promoter shows preferential expression in roots in the absence of potassium.