Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1994 Nov;106(3):1123–1129. doi: 10.1104/pp.106.3.1123

Alteration of the Amount of the Chloroplast Phosphate Translocator in Transgenic Tobacco Affects the Distribution of Assimilate between Starch and Sugar.

S A Barnes 1, J S Knight 1, J C Gray 1
PMCID: PMC159639  PMID: 12232394

Abstract

Tobacco plants (Nicotiana tabacum L.) transformed with sense and antisense constructs of a cDNA encoding the tobacco phosphate-triose phosphate-3-phosphoglycerate translocator (phosphate translocator) were shown to contain altered amounts of phosphate translocator mRNA and protein. Phosphate translocator activity in intact chloroplasts isolated from transformed plants showed a 15-fold variation, from 20% of the wild-type activity in antisense transformants to 300% of the wild-type activity in sense transformants. However, the maximal rates of photosynthesis and the rates of photosynthetic carbon assimilation in ambient CO2 showed no consistent differences between transformants. Starch content was decreased by 20% and total soluble sugars were increased by 20% in leaves of antisense transformants compared to sense transformants. The 40% decrease in the ratio of starch to total soluble sugars in antisense transformants relative to sense transformants indicates that distribution of assimilate between starch and sugar had been altered. However, the amount of sucrose in the leaves was unchanged. The changes in total soluble sugars were accounted for completely by changes in glucose and fructose, suggesting the existence of a homeostatic mechanism for maintaining sucrose concentrations in the leaves at the expense of glucose and fructose.

Full Text

The Full Text of this article is available as a PDF (1.2 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Apel K., Kloppstech K. The plastid membranes of barley (Hordeum vulgare). Light-induced appearance of mRNA coding for the apoprotein of the light-harvesting chlorophyll a/b protein. Eur J Biochem. 1978 Apr 17;85(2):581–588. doi: 10.1111/j.1432-1033.1978.tb12273.x. [DOI] [PubMed] [Google Scholar]
  2. Arnon D. I. COPPER ENZYMES IN ISOLATED CHLOROPLASTS. POLYPHENOLOXIDASE IN BETA VULGARIS. Plant Physiol. 1949 Jan;24(1):1–15. doi: 10.1104/pp.24.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bevan M. Binary Agrobacterium vectors for plant transformation. Nucleic Acids Res. 1984 Nov 26;12(22):8711–8721. doi: 10.1093/nar/12.22.8711. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fliege R., Flügge U. I., Werdan K., Heldt H. W. Specific transport of inorganic phosphate, 3-phosphoglycerate and triosephosphates across the inner membrane of the envelope in spinach chloroplasts. Biochim Biophys Acta. 1978 May 10;502(2):232–247. doi: 10.1016/0005-2728(78)90045-2. [DOI] [PubMed] [Google Scholar]
  5. Flügge U. I., Heldt H. W. Identification of a protein involved in phosphate transport of chloroplasts. FEBS Lett. 1976 Oct 1;68(2):259–262. doi: 10.1016/0014-5793(76)80449-8. [DOI] [PubMed] [Google Scholar]
  6. Gerhardt R., Stitt M., Heldt H. W. Subcellular Metabolite Levels in Spinach Leaves : Regulation of Sucrose Synthesis during Diurnal Alterations in Photosynthetic Partitioning. Plant Physiol. 1987 Feb;83(2):399–407. doi: 10.1104/pp.83.2.399. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Goldschmidt E. E., Huber S. C. Regulation of photosynthesis by end-product accumulation in leaves of plants storing starch, sucrose, and hexose sugars. Plant Physiol. 1992 Aug;99(4):1443–1448. doi: 10.1104/pp.99.4.1443. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Gray J. C., Kung S. D., Wildman S. G. Polypeptide chains of the large and small subunits of fraction I protein from tobacco. Arch Biochem Biophys. 1978 Jan 15;185(1):272–281. doi: 10.1016/0003-9861(78)90167-4. [DOI] [PubMed] [Google Scholar]
  9. Heldt W. H., Werdan K., Milovancev M., Geller G. Alkalization of the chloroplast stroma caused by light-dependent proton flux into the thylakoid space. Biochim Biophys Acta. 1973 Aug 31;314(2):224–241. doi: 10.1016/0005-2728(73)90137-0. [DOI] [PubMed] [Google Scholar]
  10. Joyard J., Grossman A., Bartlett S. G., Douce R., Chua N. H. Characterization of envelope membrane polypeptides from spinach chloroplasts. J Biol Chem. 1982 Jan 25;257(2):1095–1101. [PubMed] [Google Scholar]
  11. Knight J. S., Gray J. C. Expression of genes encoding the tobacco chloroplast phosphate translocator is not light-regulated and is repressed by sucrose. Mol Gen Genet. 1994 Mar;242(5):586–594. doi: 10.1007/BF00285282. [DOI] [PubMed] [Google Scholar]
  12. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  13. Madueño F., Napier J. A., Cejudo F. J., Gray J. C. Import and processing of the precursor of the Rieske FeS protein of tobacco chloroplasts. Plant Mol Biol. 1992 Oct;20(2):289–299. doi: 10.1007/BF00014496. [DOI] [PubMed] [Google Scholar]
  14. Shen W. J., Forde B. G. Efficient transformation of Agrobacterium spp. by high voltage electroporation. Nucleic Acids Res. 1989 Oct 25;17(20):8385–8385. doi: 10.1093/nar/17.20.8385. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Stitt M., Heldt H. W. Control of Photosynthetic Sucrose Synthesis by Fructose 2,6-Bisphosphate : VI. Regulation of the Cytosolic Fructose 1,6-Bisphosphatase in Spinach Leaves by an Interaction between Metabolic Intermediates and Fructose 2,6-Bisphosphate. Plant Physiol. 1985 Nov;79(3):599–608. doi: 10.1104/pp.79.3.599. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES