An enlarged cell wall proteome of Arabidopsis thaliana rosettes

Abstract

Plant cells are surrounded by cell walls playing many roles during development and in response to environmental constraints. Cell walls are mainly composed of polysaccharides (cellulose, hemicelluloses and pectins), but they also contain proteins which are critical players in cell wall remodeling processes. Today, the cell wall proteome of Arabidopsis thaliana, a major dicot model plant, comprises more than 700 proteins predicted to be secreted (cell wall proteins-CWPs) identified in different organs or in cell suspension cultures. However, the cell wall proteome of rosettes is poorly represented with only 148 CWPs identified after extraction by vacuum infiltration. This new study allows enlarging its coverage. A destructive method starting with the purification of cell walls has been performed and two experiments have been compared. They differ by the presence/absence of protein separation by a short 1D-electrophoresis run prior to tryptic digestion and different gradient programs for peptide separation before mass spectrometry analysis. Altogether, the rosette cell wall proteome has been significantly enlarged to 361 CWPs, among which 213 newly identified in rosettes and 57 newly described. The identified CWPs fall in four major functional classes: 26.1% proteins acting on polysaccharides, 11.1% oxido-reductases, 14.7% proteases and 11.7% proteins possibly related to lipid metabolism.

The ArathEULS3 Lectin Ends up in Stress Granules and Can Follow an Unconventional Route for Secretion

“…Gilbert and Schulze (2019) identified ArathEULS3 peptides in Arabidopsis root membranes [49]. Additionally, peptides derived from ArathEULS3 were found in the cell wall proteome of A. thaliana rosettes and mature stems [50,51]. Moreover, the experiment investigating the cell wall proteome of two Arabidopsis ecotypes Columbia (Col) and Shahdara (Sha) grown at 22 • C and at 15 • C, respectively, revealed an increase in ArathEULS3 peptides in both ecotypes at a lower temperature [52].…”

SNAREs SYP121 and SYP122 Mediate the Secretion of Distinct Cargo Subsets

“…The proportions of proteins that we identified with signal peptides, membrane anchors, or transmembrane domains are comparable with similar proteomic studies ( Supplemental Table S4). Hervé et al (2016) recently identified 1,093 proteins from the cell walls of Arabidopsis leaves; of these, they classified 361 (33%) proteins as cell wall localized on the basis of possessing a signal peptide or a transmembrane domain and lacking retention signals. Of the cell wall proteome of Hervé et al (2016), 72 proteins are in common with our data set.…”

“…Hervé et al (2016) recently identified 1,093 proteins from the cell walls of Arabidopsis leaves; of these, they classified 361 (33%) proteins as cell wall localized on the basis of possessing a signal peptide or a transmembrane domain and lacking retention signals. Of the cell wall proteome of Hervé et al (2016), 72 proteins are in common with our data set. Rutter and Innes (2017) isolated extracellular vesicles from Arabidopsis leaves and identified 598 proteins in total, 204 (34%) of which they classified as extracellular.…”

Cell wall proteome analysis of Arabidopsis thaliana mature stems

“…With this new cell wall proteomics study, the total number of A. thaliana CWPs identified is of 805, that is between two fifths and one half of the expected total number of CWPs . The cell wall proteomics atlas of A. thaliana thus remains the best described, including large proteomes for all vegetative organs (roots, rosettes and stems) as well as etiolated hypocotyls and cell suspension cultures . This description should now be completed by the analysis of different stages of development of each organ and of post‐translational modifications.…”