Selection and molecular characterization of a high tocopherol accumulation rice mutant line induced by gamma irradiation

Mol Biol Rep. 2014 Nov;41(11):7671-81. doi: 10.1007/s11033-014-3660-1. Epub 2014 Aug 7.

Abstract

Tocopherols are micronutrients with antioxidant properties. They are synthesized by photosynthetic bacteria and plants, and play important roles in animal and human nutrition. In this study, we isolated a new rice mutant line with elevated tocopherol content (MRXII) from an in vitro mutagenized population induced by gamma irradiation. The mutant exhibited greater seed longevity than the control, indicating a crucial role for tocopherols in maintaining viability during quiescence, and displayed faster seedling growth during the early growth stage. To study the molecular mechanism underlying vitamin E biosynthesis, we examined the expression patterns of seven rice genes encoding vitamin E biosynthetic enzymes. Accumulation levels of the OsVTE2 transcript and OsVTE2 protein in the MRXII mutant were significantly higher than in the control. Sequence analysis revealed that the MRXII mutant harbored a point mutation in the OsVTE2 promoter region, which resulted in the generation of MYB transcription factor-binding cis-element. These results help identify the promoter regions that regulate OsVTE2 transcription, and offer insights into the regulation of tocopherol content.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkyl and Aryl Transferases / genetics
  • Alkyl and Aryl Transferases / metabolism
  • Base Sequence
  • Biosynthetic Pathways / genetics
  • Biosynthetic Pathways / physiology*
  • Chromatography, High Pressure Liquid
  • DNA Primers / genetics
  • Gamma Rays*
  • Molecular Sequence Data
  • Oryza / genetics*
  • Oryza / metabolism*
  • Oryza / radiation effects
  • Real-Time Polymerase Chain Reaction
  • Seedlings / growth & development
  • Seedlings / metabolism
  • Seeds / metabolism*
  • Sequence Analysis, DNA
  • Tocopherols / pharmacokinetics*
  • Vitamin E / biosynthesis*

Substances

  • DNA Primers
  • Vitamin E
  • Alkyl and Aryl Transferases
  • Tocopherols