Functional analysis of the promoter of a rice 18 kDa oleosin gene

• Published in: Plant Biotechnology 2016/09/30, Vol.33(3), pp.195-200
• Main Authors: Ishibashi, Yuko, Takanashi, Hideki, Yoshida, Kaoru T.
• Format: Article
• Language: English
• Subjects: Abscisic acid; aleurone layer; cis-acting element; Drought; embryo; Embryos; Functional analysis; Gene deletion; Gene expression; GUS; Histochemical analysis; Oleosin; Oryza sativa; Oryza sativa L; Quantitative analysis; Regulatory sequences; Reporter gene; Rice; Seeds
• ISSN: 1342-4580; 1347-6114
• DOI: 10.5511/plantbiotechnology.16.0908a

The 18 kDa oleosin (Ole18) is a seed-specific protein expressed specifically in embryos and the aleurone layers of rice (Oryza sativa L.) seeds. Sequence analysis revealed that the promoter of the gene Ole18 contains many cis-acting elements, including seed-specific elements, ABA-responsive elements, and drought-responsive elements, mainly in the region between −400 and −100. To elucidate the regulatory mechanism of Ole18 gene expression, the 1249-bp Ole18 promoter and its internal deletion-derivatives were fused to the GUS reporter gene and introduced into rice. Histochemical analysis and fluorometric quantitative analysis in transgenic rice showed that GUS activity varied depending on the deletion-derivative construct. GUS activity decreased as the deletion region increased (from −378 to −187, to −180, to −169, and to −130), suggesting the importance of known cis-acting motifs such as ABA-responsive elements and drought-responsive elements, and a novel motif within these regions. In addition, either the region between −378 and −179 or that between −179 and −130 was sufficient to induce high expression in the embryos and aleurone layers. This suggests the importance of the common cis-acting elements in the two regions: the drought-responsive element DRE2 and the ABA-responsive element ABI4-binding motifs.