biologia plantarum

Biologia plantarum 57:395-400, 2013 | DOI: 10.1007/s10535-012-0298-5

Overexpression of homogentisate phytyltransferase (HPT) and tocopherol cyclase (TC) enhances α-tocopherol content in transgenic tobacco

M. C. Harish^1,2, P. Dachinamoorthy¹, S. Balamurugan¹, S. Bala Murugan¹, R. Sathishkumar^1,2,*

¹ Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, India

² DRDO-BU Centre for Life Sciences, Bharathiar University, Coimbatore, India

Photosynthetic organisms synthesize the amphipathic antioxidants called tocopherols which are essential components of the human diet. To increase the α-tocopherol (vitamin E) content, Arabidopsis genes encoding homogentisate phytyltransferase (HPT) and tocopherol cyclase (TC) were constitutively expressed individually and in combination (HPT:TC) in tobacco plant by Agrobacterium mediated transformation. The transgene was confirmed by polymerase chain reaction (PCR), transgene expression was studied by reverse transcriptase (RT)-PCR, integration of the transgene in the plant genome was confirmed by Southern blot, and α-tocopherol content was quantified using high performance liquid chromatography (HPLC). The α-tocopherol content in transgenic tobacco plants expressing HPT, TC, and HPT:TC was increased by 5.4-, 4.0-, and 7.1-fold, respectively, when compared to the wild type (WT). These results indicate that, the HPT and TC activities are critical for enhancing the vitamin E content in tobacco plants.

Keywords: Agrobacterium mediated transformation; RT-PCR; Southern blot

Subjects: gene expression; homogentisate phytyltransferase; tocopherol cyclase; tocopherol; transgenic plants; tobacco; RT-PCR; Southern blot; chlorophyll; ascorbic acid; phenolics

Received: December 10, 2011; Accepted: October 12, 2012; Published: June 1, 2013  Show citation