A Cell Wall Proteome and Targeted Cell Wall Analyses Provide Novel Information on Hemicellulose Metabolism in Flax

International audienceExperimentally-generated (nanoLC-MS/MS) proteomic analyses of four different flax organs/tissues (inner-stem, outer-stem, leaves and roots) enriched in proteins from 3 different sub-compartments (soluble-, membrane-, and cell wall-proteins) was combined with publically available data on flax seed and whole-stem proteins to generate a flax protein database containing 2996 nonredundant total proteins. Subsequent multiple analyses (MapMan, CAZy, WallProtDB and expert curation) of this database were then used to identify a flax cell wall proteome consisting of 456 nonredundant proteins localized in the cell wall and/or associated with cell wall biosynthesis, remodeling and other cell wall related processes. Examination of the proteins present in different flax organs/tissues provided a detailed overview of cell wall metabolism and highlighted the importance of hemicellulose and pectin re-modeling in stem tissues. Phylogenetic analyses of proteins in the cell wall proteome revealed an important paralogy in the class IIIA xyloglucan endo-transglycosy-lase/hydrolase (XTH) family associated with xyloglucan endo-hydrolase activity. Immunolocalisation, FT-IR microspectroscopy, and en-zymatic fingerprinting indicated that flax fiber primary/S1 cell walls contained xyloglucans with typical substituted side chains as well as glucuronoxylans in much lower quantities. These results suggest a likely central role of xyloglucans and endotransglucosylase/hydrolase activity in flax fiber formation and cell wall remodeling processes. Molecular & Cellula

Dynamique de repousse chez Trifolium repens (trèfle blanc) en relation avec la morphogenèse et l'azote protéique de réserve (Caractérisation physiologique et moléculaire des VSP)

CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Morphological pattern of development affects the contribution of nitrogen reserves to regrowth of defoliated white clover (Trifolium repens L.)

International audienc

Effects of a cold treatment of the root system on white clover (Trifolium repens L.) morphogenesis and nitrogen reserve accumulation

44 ref.International audienc

Influence of cutting frequency on the morphology and the C and N reserve status of two cultivars of white clover (Trifolium repens L.)

International audienc

The quest for tolerant varieties: the importance of integrating "omics" techniques to phenotyping

The primary objective of crop breeding is to improve yield and/or harvest quality while minimizing inputs. Global climate change and the increase in world population are significant challenges for agriculture and call for further improvements to crops and the development of new tools for research. Significant progress has been made in the molecular and genetic analysis of model plants. However, is science generating false expectations? Are 'omic techniques generating valuable information that can be translated into the field? The exploration of crop biodiversity and the correlation of cellular responses to stress tolerance at the plant level is currently a challenge. This viewpoint reviews concisely the problems one encounters when working on a crop and provides an outline of possible workflows when initiating cellular phenotyping via "-omic" techniques (transcriptomics, proteomics, metabolomics).status: publishe

Vegetative storage proteins in white clover (Trifolium repens L.) : quantitative and qualitative features

International audienceThe kinetic pattern of protein mobilization in roots, stolons and nodules of white clover (Trifolium repens cv. Grasslands Huia) was studied over a regrowth period following complete defoliation. Defoliation led to a significant decrease in soluble protein in stolons and roots during the first days of regrowth as compared with uncut plants, Protein degradation was also observed in nodules of both uncut and defoliated plants. Two of the proteins characterized (15 and 17.3 kDa), which accumulate mainly in perennial tissues. have previously been referred to as Vegetative Storage Proteins (VSPs). Using plants inoculated with either efficient (potentially functional) or inefficient Rhizobium strains, the 15 kDa VSP appeared to be located exclusively in the nodules. and it cross-reacted positively with antibodies raised against soybean leghaemoglobin. Nevertheless, the kinetics of its hydrolysis-accumulation following defoliation clearly supported the view that it may play a role in nitrogen storage. The 17.3 kDa protein was shown to accumulate in response to exposure to low temperature. and exhibited a seasonal pattern of relative accumulation under field conditions. Results are discussed in terms of the putative role that this VSP may play in overwintering of clover

A cytosolic vegetative storage protein (TrVSP) of white clover is encoded by a cold-inducible gene

The stolons of white clover (Trifolium repens L.) contain a predominant 17.3-kDa protein, previously characterized as a vegetative storage protein (VSP), which accumulates under autumn and winter conditions. Its full-length complementary DNA, TrVsp, was obtained and its 157 amino acid sequence deduced. This VSP has common characteristics to stress-responsive proteins (high neutral amino acid content and potential alpha helices in its secondary structure) and shows high homologies to abscisic acid-responsive and pathogenesis-related-10 proteins. The lack of any common amino acid sequence domains with known dehydrins or late embryogenesis abundant proteins suggests that clover VSP is not related to these proteins. Antibodies raised against the protein were produced and used in light and electron microscopic studies to show that it is localized to the cytosol of cortical parenchyma cells. This is in agreement with the VSP sequence, which does not contain any transit peptide signal. The accumulation of the transcript and the protein in roots is quickly induced by root chilling, suggesting a direct transcriptional regulation of TrVsp in response to low temperatures. Altogether, these results suggest that the 17.3-kDa protein may have an additional or alternative function to its role in nitrogen storage and may confer putative tolerance to chilling in white clover