Understanding the Remodelling of Cell Walls during Brachypodium distachyon Grain Development through a Sub-Cellular Quantitative Proteomic Approach

Abstract

Brachypodium distachyon is a suitable plant model for studying temperate cereal crops, such as wheat, barley or rice, and helpful in the study of the grain cell wall. Indeed, the most abundant hemicelluloses that are in the B. distachyon cell wall of grain are (1-3)(1-4)-β-glucans and arabinoxylans, in a ratio similar to those of cereals such as barley or oat. Conversely, these cell walls contain few pectins and xyloglucans. Cell walls play an important role in grain physiology. The modifications of cell wall polysaccharides that occur during grain development and filling are key in the determination of the size and weight of the cereal grains. The mechanisms required for cell wall assembly and remodelling are poorly understood, especially in cereals. To provide a better understanding of these processes, we purified the cell wall at three developmental stages of the B. distachyon grain. The proteins were then extracted, and a quantitative and comparative LC-MS/MS analysis was performed to investigate the protein profile changes during grain development. Over 466 cell wall proteins (CWPs) were identified and classified according to their predicted functions. This work highlights the different proteome profiles that we could relate to the main phases of grain development and to the reorganization of cell wall polysaccharides that occurs during these different developmental stages. These results provide a good springboard to pursue functional validation to better understand the role of CWPs in the assembly and remodelling of the grain cell wall of cereals.

Glycoside Hydrolases in Plant Cell Wall Proteomes: Predicting Functions That Could Be Relevant for Improving Biomass Transformation Processes

“…Ten GH3s have been identified in sugarcane [28][29][30] and nine GH3s have been identified in B. distachyon [31,32,34]. Half of the sugarcane GH3 are predicted to have a β-glucosidase activity (GO:0008422) (e.g., SCEZLB1007A09, SCEQLR1093F09, and SCQSLR1089A04).…”

“…In B. distachyon, 114 CW GHs were identified in cell wall proteomes [31][32][33][34]. They are distributed into 21 families.…”

Cell Wall Proteome Investigation of Bread Wheat (Triticum Aestivum) Developing Grain in Endosperm and Outer Layers

“…This corresponded to a proportion of CWPs of 15.8% for endosperm and 25.6% for outer layers. These yields are slightly lower than those of previous studies using similar protocols for cell wall enrichment and protein extraction . We assume that the amount of intracellular proteins (Table S7, Supporting Information) was particularly high in the endosperm samples probably due to their low proportion of cell walls at this developmental stage.…”

“…Cell wall proteomes of some monocot species like Oryza sativa, Brachypodium distachyon , or Saccharum officinarum have also been investigated but few studies have focused on their grains . Recently, the cell wall proteome of the B. distachyon grain, a model plant for Poaceae , has been published . The data were obtained at different stages of grain development, giving a dynamic view of cell wall organization.…”

Cell Wall Proteomics as a Means to Identify Target Genes to Improve Second‐Generation Biofuel Production

“…These organs were studied in order to compare the diferences between organs and to look for proteins possibly involved in cell wall extension and growth arrest. Grains were collected at diferent times after lowering , 13 or 1 days [31,61]. The aim of the study was to understand the modiications of cell wall polysaccharides during grain development and illing because they are key determinant of the size and mass of the grain.…”