Vascular expression driven by the promoter of a gene encoding a high-affinity potassium transporter HAK5 from Eucalyptus grandis

Author(s)

Costa, Carolina S. ^[1] ; Bravo, Juliana P. ^[1] ; Ribeiro, Cintia L. ^{[1, 2]} ; Soprano, Adriana S. ^[1] ; Sassaki, Flavio T. ^{[1, 3]} ; Maia, Ivan G. ^{[4, 1]}

Affiliation

^[1] UNESP, Inst Biociencias, Dept Genet, BR-18618689 Botucatu, SP - Brazil

^[2] Monsanto Co, 700 Chesterfield Pkwy W, Chesterfield, MO 63017 - USA

^[3] Univ Fed Uberlandia, Inst Genet & Bioquim, Campus Monte Carmelo, Rodovia LMG 746, Monte Carmelo, MG - Brazil

^[4] UNESP, Inst Biociencias, Dept Genet, BR-18618970 Botucatu, SP - Brazil

• Document type: Journal article
• Source: PLANT CELL TISSUE AND ORGAN CULTURE; v. 131, n. 2, p. 213-222, NOV 2017.
• Web of Science Citations: 2

Abstract

The construction of expression cassettes harboring tissue-specific promoters is a viable alternative to limit transgene expression to specific organs and cell types. In this study, we have functionally characterized the promoter of a Eucalyptus grandis gene encoding a putative high-affinity HAK5-like potassium (K+) transporter (designated EgHAK5) showing root-specific expression. The ability of the EgHAK 5'-flanking region (similar to 1.3 kb) to drive root-specific expression of a reporter gene (beta-glucuronidase; GUS) was examined using transgenic tobacco plants. Histochemical analysis revealed enhanced GUS staining in the vasculature of leaves, hypocotyls and roots, which was also confirmed in histological cross-sections. Moreover, the relative expression of GUS in the roots of the generated transgenic lines was increased in response to K+ starvation. Overall, our results indicate that, in a heterologous system, the EgHAK5 promoter shows expression in vascular tissues, mainly within the phloem, and is up-regulated upon potassium deprivation. (AU)