Molecular Breeding

, Volume 8, Issue 1, pp 75–84

Constitutive and seed-specific expression of a maize lysine-feedback-insensitive dihydrodipicolinate synthase gene leads to increased free lysine levels in rice seeds

  • Soo In Lee
  • Hyun Uk Kim
  • Yeon-Hee Lee
  • Suk-Cheol Suh
  • Yong Pyo Lim
  • Hyo-Yeon Lee
  • Ho-Il Kim
Article

DOI: 10.1023/A:1011977219926

Cite this article as:
Lee, S.I., Kim, H.U., Lee, Y. et al. Molecular Breeding (2001) 8: 75. doi:10.1023/A:1011977219926

Abstract

In order to improve the nutritional value of rice, we prepared transgenic rice plants with a lysine-feedback-insensitive maize dhps gene under the control of CaMV 35S and the rice glutelin GluB-1 promoter for over-expression and seed-specific expression. The transgenic plants were fertile and expressed the dhps gene abundantly or specifically in rice seeds. The transgenic lines (TC lines) containing mutated dhps controlled by CaMV 35S promoter possessed higher mutated DHPS transcript levels and in vitro DHPS activities in seeds than those of TS lines containing the mutated dhps gene driven by a seed-specific promoter, GluB-1. The content of free lysine in immature seeds of both TC and TS lines was higher than that of wild-type plants. The content of free lysine in mature seeds of TC lines was still higher than, but that of TS lines was similar to, that of wild-type plants. From a comparison of DHPS and lysine-ketoglutarate reductase (LKR) expression levels we conclude that the presence of the foreign dhps gene leads to an increase of LKR activity, resulting in enhanced lysine catabolism. However, over-expression of the mutant dhps gene in a constitutive manner overcomes lysine catabolism and sustains a high lysine level in mature rice seeds.

CaMV 35S promoterDihydrodipicolinate synthaseLysineRiceRice glutelin GluB-1 promoter

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Soo In Lee
    • 1
  • Hyun Uk Kim
    • 1
  • Yeon-Hee Lee
    • 1
  • Suk-Cheol Suh
    • 1
  • Yong Pyo Lim
    • 2
  • Hyo-Yeon Lee
    • 3
  • Ho-Il Kim
    • 1
  1. 1.Cytogenetics DivisionNational Institute of Agricultural Science and TechnologySuwonKorea
  2. 2.Department of HorticultureChungnam National UniversityTaejonKorea
  3. 3.Department of AgronomySunchon National UniversitySunchonKorea