This Article Full Text Full Text (PDF) All Versions of this Article: 134/3/1146    most recent pp.103.033167v1 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 ISI 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 ISI Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Konishi, T. Articles by Hayashi, T. Search for Related Content PubMed PubMed Citation Articles by Konishi, T. Articles by Hayashi, T. Agricola Articles by Konishi, T. Articles by Hayashi, T.

BIOCHEMICAL PROCESSES AND MACROMOLECULAR STRUCTURES

Evidence That Sucrose Loaded into the Phloem of a Poplar Leaf Is Used Directly by Sucrose Synthase Associated with Various -Glucan Synthases in the Stem

Wood Research Institute, Kyoto University, Uji, Kyoto 611-0011, Japan

Sucrose (Suc) synthase (SuSy) is believed to function in channeling UDP-Glc from Suc to various -glucan synthases. We produced transgenic poplars (Populus alba) overexpressing a mutant form (S11E) of mung bean (Vigna radiata) SuSy, which appeared in part in the microsomal membranes of the stems. Expression of SuSy in these membranes enhanced the incorporation of radioactive Suc into cellulose, together with the metabolic recycling of fructose (Fru), when dual-labeled Suc was fed directly into the phloem of the leaf. This overexpression also enhanced the direct incorporation of the glucosyl moiety of Suc into the glucan backbone of xyloglucan and increased recycling of Fru, although the Fru recycling system for cellulose synthesis at the plasma membrane might differ from that for xyloglucan synthesis in the Golgi network. These findings suggest that some of the Suc loaded into the phloem of a poplar leaf is used directly by SuSys associated with xyloglucan and cellulose synthases in the stem. This may be a key function of SuSy because the high-energy bond between the Glc and Fru moieties of Suc is conserved and used for polysaccharide syntheses in this sink tissue.

¹ Present address: Forest Tree Breeding Center, Juo, Ibaraki 319-1301, Japan.

^* Corresponding author; e-mail taka{at}kuwri.kyoto-u.ac.jp; fax 81-774-38-3600.

Received September 10, 2003; returned for revision October 6, 2003; accepted December 20, 2003.

This article has been cited by other articles:

				D. Persia, G. Cai, C. Del Casino, C. Faleri, M. T.M. Willemse, and M. Cresti Sucrose Synthase Is Associated with the Cell Wall of Tobacco Pollen Tubes Plant Physiology, August 1, 2008; 147(4): 1603 - 1618. [Abstract] [Full Text] [PDF]

				M. Klinghammer and R. Tenhaken Genome-wide analysis of the UDP-glucose dehydrogenase gene family in Arabidopsis, a key enzyme for matrix polysaccharides in cell walls J. Exp. Bot., October 1, 2007; 58(13): 3609 - 3621. [Abstract] [Full Text] [PDF]

				C Doering-Saad, H. Newbury, C. Couldridge, J. Bale, and J Pritchard A phloem-enriched cDNA library from Ricinus: insights into phloem function J. Exp. Bot., September 1, 2006; 57(12): 3183 - 3193. [Abstract] [Full Text] [PDF]

				S. C. Hardin, K. A. Duncan, and S. C. Huber Determination of Structural Requirements and Probable Regulatory Effectors for Membrane Association of Maize Sucrose Synthase 1 Plant Physiology, July 1, 2006; 141(3): 1106 - 1119. [Abstract] [Full Text] [PDF]

				E. Baroja-Fernandez, E. Etxeberria, F. J. Munoz, M. T. Moran-Zorzano, N. Alonso-Casajus, P. Gonzalez, and J. Pozueta-Romero An Important Pool of Sucrose Linked to Starch Biosynthesis is Taken up by Endocytosis in Heterotrophic Cells Plant Cell Physiol., April 1, 2006; 47(4): 447 - 456. [Abstract] [Full Text] [PDF]

				J. Geisler-Lee, M. Geisler, P. M. Coutinho, B. Segerman, N. Nishikubo, J. Takahashi, H. Aspeborg, S. Djerbi, E. Master, S. Andersson-Gunneras, et al. Poplar Carbohydrate-Active Enzymes. Gene Identification and Expression Analyses Plant Physiology, March 1, 2006; 140(3): 946 - 962. [Abstract] [Full Text] [PDF]