As a vital component of plant cell walls, proteins play important roles in stress response by modifying the structure of cell walls and involving in the wall integrity signaling pathway. Recently, we have critically reviewed the predictors, databases, and cross-referencing of the subcellular locations of possible cell wall proteins (CWPs) in plants (Briefings in Bioinformatics 2018;19:1130-1140). Here, we briefly introduce strategies for isolating CWPs during proteomic analysis. Taking maize (Zea mays) as an example, we retrieved 1873 probable maize CWPs recorded in the UniProt KnowledgeBase (UniProtKB). After curation, 863 maize CWPs were identified and classified into 59 kinds of protein families. By referring to gene ontology (GO) annotations and gene differential expression in the Expression Atlas, we have highlighted the potential of CWPs acting in the front line of defense against biotic and abiotic stresses. Moreover, the analysis results of cis-acting elements revealed the responsiveness of the genes encoding CWPs toward phytohormones and various stresses. We suggest that the stress-responsive CWPs could be promising candidates for applications in developing varieties of stressresistant maize.

Since Charles Darwin discovered growth movements of the shoot tip (coleoptile) toward light, the grass coleoptiles have long been used as a model system to study plant growth. Rapid growth of the coleoptile is vital for successful seed germination and early seedling establishment. However, the proteome changes underlying the rapid growth of the coleoptiles are not yet clear in the model plant maize (Zea mays). In the present study, we investigated proteome changes in vivo occurring in the rapidly growing coleoptiles of maize with two‐dimensional gel electrophoresis combined with mass spectrometry. A quantitative comparison of the proteomes at 1.5, 3, and 5 days after germination showed significant changes in protein profiles with coleoptile growth. As a result, 31 differential abundance proteins (DAPs) representing 44 protein spots were identified, of which 21 DAPs with increased abundances were implied in growth‐related processes, including translational initiation, transcription regulation, protein and other compound synthesis, H+‐transmembrane transport and cytoskeleton organization. The selected DAPs were confirmed by reverse transcription quantitative PCR and immunoblot analysis. We suggested that the rapid growth of the coleoptile is largely due to its ability to quickly enhance relevant cellular processes, especially the increased synthesis of the growth‐related DAPs. The content of indole‐3‐acetic acid, salicylic acid, and jasmonic acid decreased significantly, and the content of gibberellins first decreased and then increased during the elongation of coleoptile. This study provides new insight into the significance of proteome changes in coleoptile growth.

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