This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 147/4/1603    most recent pp.108.115956v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Persia, D. Articles by Cresti, M. Search for Related Content PubMed PubMed Citation Articles by Persia, D. Articles by Cresti, M. Agricola Articles by Persia, D. Articles by Cresti, M. Related Collections Membrane Trafficking

Sucrose Synthase Is Associated with the Cell Wall of Tobacco Pollen Tubes^1,[W]

Dipartimento Scienze Ambientali "G. Sarfatti," Università di Siena, 53100 Siena, Italy

Sucrose synthase (Sus; EC 2.4.1.13) is a key enzyme of sucrose metabolism in plant cells, providing carbon for respiration and for the synthesis of cell wall polymers and starch. Since Sus is important for plant cell growth, insights into its structure, localization, and features are useful for defining the relationships between nutrients, growth, and cell morphogenesis. We used the pollen tube of tobacco (Nicotiana tabacum) as a cell model to characterize the main features of Sus with regard to cell growth and cell wall synthesis. Apart from its role during sexual reproduction, the pollen tube is a typical tip-growing cell, and the proper construction of its cell wall is essential for correct shaping and direction of growth. The outer cell wall layer of pollen tubes consists of pectins, but the inner layer is composed of cellulose and callose; both polymers require metabolic precursors in the form of UDP-glucose, which is synthesized by Sus. We identified an 88-kD polypeptide in the soluble, plasma membrane and Golgi fraction of pollen tubes. The protein was also found in association with the cell wall. After purification, the protein showed an enzyme activity similar to that of maize (Zea mays) Sus. Distribution of Sus was affected by brefeldin A and depended on the nutrition status of the pollen tube, because an absence of metabolic sugars in the growth medium caused Sus to distribute differently during tube elongation. Analysis by bidimensional electrophoresis indicated that Sus exists as two isoforms, one of which is phosphorylated and more abundant in the cytoplasm and cell wall and the other of which is not phosphorylated and is specific to the plasma membrane. Results indicate that the protein has a role in the construction of the extracellular matrix and thus in the morphogenesis of pollen tubes.

² Present address: Plant Cytology and Morphology, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Giampiero Cai (cai{at}unisi.it).

^[W] The online version of this article contains Web-only data.

www.plantphysiol.org/cgi/doi/10.1104/pp.108.115956

^* Corresponding author; e-mail cai{at}unisi.it.

Received January 7, 2008; accepted March 9, 2008; published March 14, 2008.

This article has been cited by other articles:

				B. Cubero, Y. Nakagawa, X.-Y. Jiang, K.-J. Miura, F. Li, K. G. Raghothama, R. A. Bressan, P. M. Hasegawa, and J. M. Pardo The Phosphate Transporter PHT4;6 Is a Determinant of Salt Tolerance that Is Localized to the Golgi Apparatus of Arabidopsis Mol Plant, May 1, 2009; 2(3): 535 - 552. [Abstract] [Full Text] [PDF]

				A. Y. Cheung and S. C. de Vries Membrane Trafficking: Intracellular Highways and Country Roads Plant Physiology, August 1, 2008; 147(4): 1451 - 1453. [Full Text] [PDF]