Characterization of promoter expression patterns derived from the Pht1 phosphate transporter genes of barley (Hordeum vulgare L.)

• Published in: Journal of experimental botany Vol. 55; no. 398; pp. 855 - 865
• Main Authors: Schunmann, P.H.D, Richardson, A.E, Smith, F.W, Delhaize, E
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-04-2004; Oxford Publishing Limited (England)
• Subjects: Barley; Base Sequence; Biological and medical sciences; Cell physiology; DNA Primers; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant - genetics; Genes; Glucuronidase - genetics; Glucuronidase - metabolism; Hordeum - genetics; Hordeum - growth & development; Hordeum - metabolism; intron; Introns; Membrane Transport Proteins - genetics; Molecular biology; Molecular Sequence Data; phosphate transport; Phosphate Transport Proteins - genetics; Phosphates; phosphorus; Pht1 gene family; Plant Leaves - physiology; Plant physiology and development; Plant Proteins - genetics; plant root; Plant roots; Plants; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Plasma membrane and permeation; promoter; Promoter regions; Promoter Regions, Genetic - genetics; Recombinant Proteins - metabolism; Research Papers: Cell and Molecular Biology, Biochemistry and Molecular Physiology; Restriction Mapping; Rice; Ubiquitins; Phosphates; Monocotyledones; phosphate transport; Nutrition; Hordeum vulgare; Transcription promoter; Ion transport; Gene expression; intron; Gene; Gramineae; Angiospermae; Pht1 gene family; Regulatory sequence; Spermatophyta; promoter; plant root; phosphorus
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/erh103

By comparison with dicot plant species, relatively little work has been reported on the phosphate transporter (Pht1) gene family from monocot species. Initial studies have shown that barley contains at least eight homologous genes. The promoters of six of these genes were analysed for the presence of regulatory elements potentially associated with expression specificity. In particular, the P1BS-like elements (implicated in phosphorus-regulated expression of genes in plants) was identified in all HvPht1 promoters examined. For two members of the family (HvPht1;1 and HvPht1;2), promoter fusions to ß-glucuronidase and green fluorescent protein reporter genes were constructed, transformed into rice, and the expression profiles observed. The inclusion of an intron derived from Adh1 enhanced gene expression approximately 20-fold, but did not appear to affect the specificity of expression. The HvPht1;1 and HvPht1;2 promoters showed minor differences in expression patterns but, in general, expression was observed at high levels in trichoblast cells (root hairs) and stele of the nodal root, throughout secondary roots, and at a relatively low level in leaf tissues. Under phosphorus deficiency, expression was induced by up to 5-fold. These observations are consistent with a primary role for the encoded genes in the uptake of phosphate by root hairs from soil solution and further current understanding of the mechanisms involved. The promoters also have application for providing a new resource for cereal transformation, ideally suited for driving the expression of foreign genes associated with nutrient uptake.