Ectopic expression of apple fruit homogentisate phytyltransferase gene (MdHPT1) increases tocopherol in transgenic tomato (Solanum lycopersicum cv. Micro-Tom) leaves and fruits

Young Sam Seo, Soo Jin Kim, Chee Hark Harn, Woo Taek Kim

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Abstract

Homogentisate phytyltransferase (HPT) is an important enzyme in the biosynthesis of tocopherols (vitamin E). Herein, an HPT homolog (MdHPT1) was isolated from apple (Malus domestica Borkh. cv. Fuji) fruits, whose gene expression level gradually decreased during fruit ripening, reaching a background level in ripened apple fruits. The amounts of α- and γ-tocopherols, two major tocopherols in plant organs, were 5- to 14-fold lower in the fruits than in the leaves and flowers of apple plants. Transgenic tomato plants (Solanum lycopersicum cv. Micro-Tom) overexpressing MdHPT1 were next constructed. Transgenic independent T1 leaves contained ∼1.8- to 3.6-fold and ∼1.6- to 2.9-fold higher levels of α-tocopherol and γ-tocopherol, respectively, than those in control plants. In addition, the levels of α-tocopherol and γ-tocopherol in 35S:MdHPT1 T1 fruits increased up to 1.7-fold and 3.1-fold, respectively, as compared to the control fruits, indicating that an increase in α-tocopherol in fruits (maximal 1.7-fold) was less evident than that in leaves (maximal 3.6-fold). This finding suggests that the apple MdHPT1 plays a role in tocopherol production in transgenic tomatoes.

Original languageEnglish
Pages (from-to)321-329
Number of pages9
JournalPhytochemistry
Volume72
Issue number4-5
DOIs
Publication statusPublished - 2011 Apr 1

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All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Plant Science
  • Horticulture

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