Abstract:

Homogentisate Phytyltransferase (HPT) is a key enzyme catalyzing condensation of HGA and PDP in the first step of tocopherol biosynthesis. The HPT gene has been cloned from several photosynthetic organisms. Overexpression of HPT in transgenic plants increases tocopherols significantly in leaves and seeds. A mutation of the Arabidopsis HPT gene results in tocopherol deficiency in the plants. In order to understand the expression pattern of HPT, a 946 bp DNA upstream fragment of the Arabidopsis HPT gene was isolated and transcriptionally fused with the β-glucuronidase (GUS) reporter gene, and the promoter-GUS cussette was introduced into Arabidopsis thaliana by Agrobacterium-mediated transformation. Analysis of transgenic plants using histochemical staining showed that the GUS gene was expressed predominantly in the roots, and also to a lesser degree, in adult leaves, filament and pistil, but not in stems, root tips, anthers, seeds and siliqua. Our results suggested that the HPT gene was predominantly expressed in Arabidopsis roots.

Key words: Arabidopsis thaliana, Vitamin E, Tocopherol, Homogentisate Phytyltransferase (HPT), Promoter