Plant Cell Wall Proteomics: A Focus on Monocot Species, Brachypodium distachyon, Saccharum spp. and Oryza sativa

Abstract

Plant cell walls mostly comprise polysaccharides and proteins. The composition of monocots’ primary cell walls differs from that of dicots walls with respect to the type of hemicelluloses, the reduction of pectin abundance and the presence of aromatic molecules. Cell wall proteins (CWPs) differ among plant species, and their distribution within functional classes varies according to cell types, organs, developmental stages and/or environmental conditions. In this review, we go deeper into the findings of cell wall proteomics in monocot species and make a comparative analysis of the CWPs identified, considering their predicted functions, the organs analyzed, the plant developmental stage and their possible use as targets for biofuel production. Arabidopsis thaliana CWPs were considered as a reference to allow comparisons among different monocots, i.e., Brachypodium distachyon, Saccharum spp. and Oryza sativa. Altogether, 1159 CWPs have been acknowledged, and specificities and similarities are discussed. In particular, a search for A. thaliana homologs of CWPs identified so far in monocots allows the definition of monocot CWPs characteristics. Finally, the analysis of monocot CWPs appears to be a powerful tool for identifying candidate proteins of interest for tailoring cell walls to increase biomass yield of transformation for second-generation biofuels production.

Elucidating the Possible Involvement of Maize Aquaporins in the Plant Boron Transport and Homeostasis Mediated by Rhizophagus irregularis under Drought Stress Conditions

“…In fact, during vegetative stages, monocots rarely develop deficiency symptoms [37]. Different B requirements between dicots and monocots may be related to the different composition of their cell walls [38]. In addition, the tolerance of each species to B deficiency or excess is highly variety-dependent [6,39,40], and some low-demanding cultivars may increase B use efficiency, which allows them to develop with a limited amount of this nutrient [40].…”

Cell Wall Proteome of Wheat Grain Endosperm and Outer Layers at Two Key Stages of Early Development

“…The CWPs are distributed into eight of the nine functional classes, as defined by the ProtAnnDB tool [35] ( Figure 4A). No protein was annotated as a structural protein that has been currently observed in cell wall proteomes of monocots [36]. The most effective functional class was that of "proteins acting on cell wall polysaccharides" (PACs) with around a quarter of the CWPs.…”

Do plants use root-derived proteases to promote the uptake of soil organic nitrogen?

“…Investigations of the role of plant proteases in N acquisition have generally focused on proteases secreted from roots (Vágnerová and Macura 1974 ; Godlewski and Adamczyk 2007 ). Proteomic studies of the apoplast and cell wall, however, have revealed the presence of a wide range of proteases, most of which have unknown roles (Rodríguez-Celma et al 2016 ; Calderan-Rodrigues et al 2019 ). Therefore, with a focus on aminopeptidases, our aim was to determine: a) whether plants release free proteases from their roots or if the proteases remain root surface-bound, b) if proteins and/or their breakdown products are taken up by the plant, c) if root protease activity is up- or down-regulated in the presence of inorganic N and, d) how root protease activity compares to rhizosphere protease activity.…”