Deposition of Cell Wall Polysaccharides in Wheat Endosperm during Grain Development:  Fourier Transform-Infrared Microspectroscopy Study

Abstract

The time course and pattern deposition of the cell wall polysaccharides in the starchy endosperm of wheat (Triticum aestivum cv. Recital) during grain development was studied using Fourier transform infrared microspectroscopy (micro-FTIR). Three stages of grain development identified as key stages for cell wall construction were retained as follows: the end cellularization, the beginning of cell differentiation, and the beginning of maturation. Micro-FTIR revealed that β-(1→3),(1→4) glucans and arabinoglactan proteins are the main cell wall components of endosperm at the end of the cellularization stage, whereas arabinoxylans (AX) appeared only at the cell differentiation stage. Past the differentiation stage, FTIR spectra were dominated by AX features. Cell walls at the beginning of cell differentiation and at endosperm maturation could be distinguished by spectral features that were ascribed to AX substitution. AX appeared more substituted at the beginning of cell differentiation. Moreover, a difference in the degree of AX substitution was found between peripheral and central parts of the grain at the cell differentiation stage; AX in central cells was less substituted. Thus, dramatic changes in endosperm cell wall composition were detected during wheat grain development with respect to both the relative occurrence of individual constituents and the fine structure of the AX. Keywords: Arabinoxylans; endosperm; FTIR; β-(1→3),(1→4) glucans; immunolabeling; principal component analysis; Triticum aestivum

Cell wall deposition and metabolism in wheat grain

“…In the starchy endosperm, the walls of the cells close to the embryo are rich in BG from the onset of BG synthesis and throughout development. In the same tissue, the degree of di-substitution of AX by arabinose is higher at the beginning of cell differentiation than at the later stages (Philippe et al, 2006a;Philippe et al, 2006b;Saulnier et al, 2009;Toole et al, 2010).…”

“…As such the differences between cell walls from the protective outer tissues and cell walls from the storage endosperm are not surprising. However, dramatic changes also occur within one tissue, the endosperm, according to the position and the developmental stage, with respect to both the relative occurrence of individual constituents (AX and BG) and the fine structure of AX (Jamme et al, 2008;Philippe et al, 2006b;Philippe et al, 2007;Robert et al, 2011;Saulnier et al, 2009;Toole et al, 2010;Toole et al, 2007).…”

“…The sequence of deposition of cell wall polysaccharides in wheat starchy endosperm and aleurone cells has been studied using complementary techniques including biochemistry Toole et al, 2010), FT-IR and Raman micro-spectroscopy (Jamme et al, 2008;Philippe et al, 2006a;Philippe et al, 2006b;Robert et al, 2011;Saulnier et al, 2009;Toole et al, 2010), as well as immunolabelling (Philippe et al, 2006c(Philippe et al, , 2007Robert et al, 2011;Tranquet et al, 2009) (see Fig. 4).…”

Change in wall composition of transfer and aleurone cells during wheat grain development

“…The deposition sequence of (1-3)(1-4)-b-glucan and arabinoxylan in wheat starchy endosperm and aleurone cells has been studied using complementary techniques, Fourier transform infrared (FT-IR) and Raman micro-spectroscopy (Philippe et al 2006b, c;Saulnier et al 2009;Toole et al 2009Toole et al , 2010, as well as immunolabeling (Philippe et al 2006a(Philippe et al , 2007. These analyses revealed that (1-3)(1-4)-b-glucan and arabinogalactan are the main components of wheat starchy endosperm cell wall at the end of the cellularization stage (Philippe et al 2006a, b) and that arabinoxylan is more substituted at the differentiation stage than at the mature stage (Philippe et al 2006b, c;Saulnier et al 2009;Toole et al 2009Toole et al , 2010. In addition, positional variations were observed in composition and structure of cell wall polysaccharides in wheat starchy endosperm.…”

Compositional characterization and imaging of “wall-bound” acylesters of Populus trichocarpa reveal differential accumulation of acyl molecules in normal and reactive woods

“…The absorption band around 1,150 cm ¡1 was assigned to glycosidic linkages, while the small band around 890 cm ¡1 was characteristic of -(1-4) linkages ( Fig. 1) (Robert et al 2005;Philippe et al 2006). An absorption peak around 1,510 cm ¡1 , representing aromatic ring in lignin polymer, was present primarily in cell walls of poplar stem.…”