REVIEW PAPER Characterizing visible and invisible cell wall mutant phenotypes

About 10 % of a plant’s genome is devoted to generating the protein machinery to synthesize, remodel, and decon-struct the cell wall. High-throughput genome sequencing technologies have enabled a reasonably complete inventory of wall-related genes that can be assembled into families of common evolutionary origin. Assigning function to each gene family member has been aided immensely by identification of mutants with visible phenotypes or by chemical and spectroscopic analysis of mutants with ‘invisible ’ phenotypes of modified cell wall composition and architecture that do not otherwise affect plant growth or development. This review connects the inference of gene function on the basis of deviation from the wild type in genetic functional analyses to insights provided by modern analytical tech-niques that have brought us ever closer to elucidating the sequence structures of the major polysaccharide compo-nents of the plant cell wall. Key words: Capillary electrophoresis, cell wall synthesis, cell wall mutant, electrospray ionization (ESI), Fourier transform infrared (FTIR), matrix-assisted laser desorption ionization (MALDI), mass spectrometry (MS), methylation analysis, principal components analysis (PCA)