Research Article Open Access

Induced Production of α-Tocotrienol by Co-Suppression of Tocopherol Cyclase Gene in Vegetable Crops

Umaiyal Munusamy1, Siti Nor Akmar Abdullah2, Maheran Abdul Aziz2, Huzwah Khazaai2 and Lai Mun Seong2
  • 1 University of Malaya, Malaysia
  • 2 University Putra Malaysia, Malaysia


This study involves the induced production of α-tocotrienol by the co-suppression of tocopherol cyclase gene. The Tocopherol/Tocotrienol Cyclase (TC) is a key enzyme involved in the biosynthesis of α-tocotrienol. The partial conserved cDNA of TC gene isolated from the oil palm (Elaeis guineensis) that shared greater than 75% sequence identity with TC sequences from other plant species was used to silence TC gene expression in Amaranthus sp. and Allium porrum leaves by co-suppression strategies. This was carried out using recombinant vector constructs designated as p4a11 and p4c9 containing TC driven by the maize ubiquitin promoter (Ubi1P) and the oil palm leaf-specific promoter (LHCB), respectively. In the Amaranthus sp. leaves infiltrated with p4a11, the α-tocopherol suppression was 85.0, 71.0 and 74.0% on day three, five and seven, respectively and complete suppression was observed in the leaves infiltrated with p4c9. Whereas, only 11.0, 7.0 and 29.0% suppression was detected in Allium porrum leaves infiltrated with p4a11 and 45.0, 4.0 and 57.0% of suppression was observed in Allium porrum infiltrated with p4c9 on day three, five and seven, respectively. Silencing of TC gene driven by LHCB (p4c9) causes the reduction of α-tocopherol production better than by Ubi1P (p4a11). The results have demonstrated that gene silencing through co-suppression is capable of producing α-tocotrienol. However, there is no correlation between the α-tocotrienol production and the α-tocopherol suppression. It has been suggested that the transgene mediated co-suppression mechanism had triggered the vitamin E biosynthesis metabolic pathway to shift towards producing α-tocotrienol.

American Journal of Biochemistry and Biotechnology
Volume 9 No. 4, 2013, 355-364


Submitted On: 1 September 2013 Published On: 20 December 2013

How to Cite: Munusamy, U., Abdullah, S. N. A., Aziz, M. A., Khazaai, H. & Seong, L. M. (2013). Induced Production of α-Tocotrienol by Co-Suppression of Tocopherol Cyclase Gene in Vegetable Crops. American Journal of Biochemistry and Biotechnology, 9(4), 355-364.

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  • Vitamin E Biosynthetic Pathway
  • Co-Suppression
  • Tocopherol Cyclase
  • α-Tocopherol
  • α-Tocotrienol
  • Tissue-Specific Promoter