This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 146/2/441    most recent pp.107.113076v1 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 (9) Citing Articles via Google Scholar Google Scholar Articles by Xue, G.-P. Articles by Shorter, R. Search for Related Content PubMed PubMed Citation Articles by Xue, G.-P. Articles by Shorter, R. Agricola Articles by Xue, G.-P. Articles by Shorter, R.

BIOCHEMICAL PROCESSES AND MACROMOLECULAR STRUCTURES

Molecular Dissection of Variation in Carbohydrate Metabolism Related to Water-Soluble Carbohydrate Accumulation in Stems of Wheat^1,[W]

CSIRO Plant Industry, St Lucia, Brisbane, Queensland 4067, Australia (G.-P.X., C.L.M., D.G., A.F.v.H., R.S.); and CSIRO Plant Industry, Canberra, Australian Capital Territory 2601, Australia (C.L.D.J.)

Water-soluble carbohydrates (WSCs; composed of mainly fructans, sucrose [Suc], glucose [Glc], and fructose) deposited in wheat (Triticum aestivum) stems are important carbon sources for grain filling. Variation in stem WSC concentrations among wheat genotypes is one of the genetic factors influencing grain weight and yield under water-limited environments. Here, we describe the molecular dissection of carbohydrate metabolism in stems, at the WSC accumulation phase, of recombinant inbred Seri/Babax lines of wheat differing in stem WSC concentrations. Affymetrix GeneChip analysis of carbohydrate metabolic enzymes revealed that the mRNA levels of two fructan synthetic enzyme families (Suc:Suc 1-fructosyltransferase and Suc:fructan 6-fructosyltransferase) in the stem were positively correlated with stem WSC and fructan concentrations, whereas the mRNA levels of enzyme families involved in Suc hydrolysis (Suc synthase and soluble acid invertase) were inversely correlated with WSC concentrations. Differential regulation of the mRNA levels of these Suc hydrolytic enzymes in Seri/Babax lines resulted in genotypic differences in these enzyme activities. Down-regulation of Suc synthase and soluble acid invertase in high WSC lines was accompanied by significant decreases in the mRNA levels of enzyme families related to sugar catabolic pathways (fructokinase and mitochondrion pyruvate dehydrogenase complex) and enzyme families involved in diverting UDP-Glc to cell wall synthesis (UDP-Glc 6-dehydrogenase, UDP-glucuronate decarboxylase, and cellulose synthase), resulting in a reduction in cell wall polysaccharide contents (mainly hemicellulose) in the stem of high WSC lines. These data suggest that differential carbon partitioning in the wheat stem is one mechanism that contributes to genotypic variation in WSC accumulation.

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: Gang-Ping Xue (gang-ping.xue{at}csiro.au).

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

www.plantphysiol.org/cgi/doi/10.1104/pp.107.113076

^* Corresponding author; e-mail gang-ping.xue{at}csiro.au.

Received November 11, 2007; accepted December 8, 2007; published December 14, 2007.

This article has been cited by other articles:

				B. Lasseur, L. Schroeven, W. Lammens, K. Le Roy, G. Spangenberg, H. Manduzio, R. Vergauwen, J. Lothier, M.-P. Prud'homme, and W. Van den Ende Transforming a Fructan:Fructan 6G-Fructosyltransferase from Perennial Ryegrass into a Sucrose:Sucrose 1-Fructosyltransferase Plant Physiology, January 1, 2009; 149(1): 327 - 339. [Abstract] [Full Text] [PDF]

				R. Valluru and W. Van den Ende Plant fructans in stress environments: emerging concepts and future prospects J. Exp. Bot., August 1, 2008; 59(11): 2905 - 2916. [Abstract] [Full Text] [PDF]