Abstract
Immature green tomato (Lycopersicon esculentum) fruits undergo a period of transient starch accumulation characterized by developmental changes in the activities of key enzymes in the sucrose (Suc)-to-starch metabolic pathway. Activities of Suc synthase, fructokinase, ADP-glucose (Glc) pyrophosphorylase, and soluble and insoluble starch synthases decline dramatically in parallel to the decrease in starch levels in the developing fruit. Comparison of "maximal" in vitro activities of the enzymes in the Suc-to-starch pathway suggests that these same enzymes are limiting to the rate of starch accumulation. In contrast, activities of invertase, UDP-Glc pyrophosphorylase, nucleoside diphosphate kinase, phosphoglucoisomerase, and phosphoglucomutase do not exhibit dramatic decreases in activity and appear to be in excess of starch accumulation rates. Starch accumulation is spatially localized in the inner and radial pericarp and columella, whereas the outer pericarp and seed locule contain little starch. The seed locule is characterized by lower activities of Suc synthase, UDP-Glc pyrophosphorylase, phosphoglucomutase, ADP-Glc pyrophosphorylase, and soluble and insoluble starch synthases. The outer pericarp exhibits comparatively lower activities of ADP-Glc pyrophosphorylase and insoluble starch synthase only. These data are discussed in terms of the developmental and tissue-specific coordinated control of Suc-to-starch metabolism.
Full Text
The Full Text of this article is available as a PDF (1.3 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Amor Y., Haigler C. H., Johnson S., Wainscott M., Delmer D. P. A membrane-associated form of sucrose synthase and its potential role in synthesis of cellulose and callose in plants. Proc Natl Acad Sci U S A. 1995 Sep 26;92(20):9353–9357. doi: 10.1073/pnas.92.20.9353. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ching T. M., Poklemba C. J., Metzger R. J. Starch synthesis in shriveled and plump triticale seeds. Plant Physiol. 1983 Nov;73(3):652–657. doi: 10.1104/pp.73.3.652. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dancer J., Neuhaus H. E., Stitt M. Subcellular compartmentation of uridine nucleotides and nucleoside-5' -diphosphate kinase in leaves. Plant Physiol. 1990 Mar;92(3):637–641. doi: 10.1104/pp.92.3.637. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Denyer K., Dunlap F., Thorbjørnsen T., Keeling P., Smith A. M. The major form of ADP-glucose pyrophosphorylase in maize endosperm is extra-plastidial. Plant Physiol. 1996 Oct;112(2):779–785. doi: 10.1104/pp.112.2.779. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Doehlert D. C., Kuo T. M., Felker F. C. Enzymes of sucrose and hexose metabolism in developing kernels of two inbreds of maize. Plant Physiol. 1988 Apr;86(4):1013–1019. doi: 10.1104/pp.86.4.1013. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Guan H. P., Janes H. W. Light Regulation of Sink Metabolism in Tomato Fruit : II. Carbohydrate Metabolizing Enzymes. Plant Physiol. 1991 Jul;96(3):922–927. doi: 10.1104/pp.96.3.922. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miron D., Schaffer A. A. Sucrose Phosphate Synthase, Sucrose Synthase, and Invertase Activities in Developing Fruit of Lycopersicon esculentum Mill. and the Sucrose Accumulating Lycopersicon hirsutum Humb. and Bonpl. Plant Physiol. 1991 Feb;95(2):623–627. doi: 10.1104/pp.95.2.623. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ozbun J. L., Hawker J. S., Greenberg E., Lammel C., Preiss J. Starch Synthetase, Phosphorylase, ADPglucose Pyrophosphorylase, and UDPglucose Pyrophosphorylase in Developing Maize Kernels. Plant Physiol. 1973 Jan;51(1):1–5. doi: 10.1104/pp.51.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Robinson N. L., Hewitt J. D., Bennett A. B. Sink metabolism in tomato fruit : I. Developmental changes in carbohydrate metabolizing enzymes. Plant Physiol. 1988 Jul;87(3):727–730. doi: 10.1104/pp.87.3.727. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sebková V., Unger C., Hardegger M., Sturm A. Biochemical, physiological, and molecular characterization of sucrose synthase from Daucus carota. Plant Physiol. 1995 May;108(1):75–83. doi: 10.1104/pp.108.1.75. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stark D. M., Timmerman K. P., Barry G. F., Preiss J., Kishore G. M. Regulation of the Amount of Starch in Plant Tissues by ADP Glucose Pyrophosphorylase. Science. 1992 Oct 9;258(5080):287–292. doi: 10.1126/science.258.5080.287. [DOI] [PubMed] [Google Scholar]
- Sun J., Loboda T., Sung S. J., Black C. C. Sucrose Synthase in Wild Tomato, Lycopersicon chmielewskii, and Tomato Fruit Sink Strength. Plant Physiol. 1992 Mar;98(3):1163–1169. doi: 10.1104/pp.98.3.1163. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wang F., Sanz A., Brenner M. L., Smith A. Sucrose Synthase, Starch Accumulation, and Tomato Fruit Sink Strength. Plant Physiol. 1993 Jan;101(1):321–327. doi: 10.1104/pp.101.1.321. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wang F., Smith A. G., Brenner M. L. Temporal and Spatial Expression Pattern of Sucrose Synthase during Tomato Fruit Development. Plant Physiol. 1994 Feb;104(2):535–540. doi: 10.1104/pp.104.2.535. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Xu D. P., Sung S. J., Black C. C. Sucrose metabolism in lima bean seeds. Plant Physiol. 1989 Apr;89(4):1106–1116. doi: 10.1104/pp.89.4.1106. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yelle S., Chetelat R. T., Dorais M., Deverna J. W., Bennett A. B. Sink Metabolism in Tomato Fruit : IV. Genetic and Biochemical Analysis of Sucrose Accumulation. Plant Physiol. 1991 Apr;95(4):1026–1035. doi: 10.1104/pp.95.4.1026. [DOI] [PMC free article] [PubMed] [Google Scholar]