Planta

, Volume 212, Issue 5, pp 817–822

Promoter strength and tissue specificity effects on growth of tomato plants transformed with maize sucrose-phosphate synthase

  • Marianne M. Laporte
  • Julie A. Galagan
  • Amy L. Prasch
  • Peter J. Vanderveer
  • David T. Hanson
  • Christine K. Shewmaker
  • Thomas D. Sharkey

DOI: 10.1007/s004250000433

Cite this article as:
Laporte, M., Galagan, J., Prasch, A. et al. Planta (2001) 212: 817. doi:10.1007/s004250000433

Abstract.

When sucrose-phosphate synthase (SPS; EC 2.4.1.14) is expressed in tomato (Lycopersicon esculentum Mill.) from a ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) small subunit (rbcS) promoter, yields are often unchanged but when SPS is expressed from a Cauliflower Mosaic Virus 35S promoter, yield is enhanced up to 80%. Two explanations for this phenomenon are (i) that expression of SPS in tissues other than leaves accounts for the increased yield or (ii) that the lower level of expression directed by the 35S promoter is more beneficial than the high level of expression directed by the rbcS promoter. To test the first hypothesis, we conducted a reciprocal graft experiment, which showed that root SPS activity did not substantially affect growth. To test the second hypothesis, we conducted a field trial using a backcrossed, segregating, population of SPS-transformed plants derived from 35S and rbcS lines. The optimal dose of SPS activity for growth was approximately twice that of the wild type regardless of which promoter was used. The effect of SPS on growth was the result of a shift in partitioning of carbon among starch, sucrose, and ionic compounds (primarily amino acids), rather than of an increase in net photosynthesis. Excessive SPS activity resulted in a decreased rate of amino acid synthesis, which could explain the non-linear response of plant growth to the level of SPS expression.

Key words: Carbon partitioningCaMV 35S promoterLycopersicon (carbon partitioning)rbcS promoterSucrose-phosphate synthaseTransgenic tomato

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Marianne M. Laporte
    • 1
  • Julie A. Galagan
    • 1
  • Amy L. Prasch
    • 1
  • Peter J. Vanderveer
    • 1
  • David T. Hanson
    • 1
  • Christine K. Shewmaker
    • 2
  • Thomas D. Sharkey
    • 1
  1. 1.Department of Botany, University of Wisconsin, 430 Lincoln Drive, Madison, WI 53706, USAUS
  2. 2.Calgene, Inc., 1920 5th Street, Davis, CA 95616, USAUS