Mass distribution profiling of cell wall matrix polysaccharide biosynthesis mutants reveals alterations in...

Plant cell walls contain multiple matrix polysaccharides whose interactions help determine wall mechanics, growth, and integrity, but it remains unclear how disruption of one biosynthetic or modification pathway reshapes other, non-target polymers. We used gel permeation chromatography coupled with enzyme-linked immunosorbent assay (GPC-ELISA) to compare mass distributions of major matrix polysaccharides in Arabidopsis thaliana mutants affecting xylan biosynthesis and decoration (irx14L, irx15, gux1-1, and gux2-2), glucomannan synthesis (csla2-1), pectin homogalacturonan (HG) biosynthesis (gaut10-2 and gaut11-2), and wall esterification (axy4-4, tbl31, tbl2, tbl3, and tbr). Three biological replicates per genotype, each from independent cell wall extractions, were profiled. Disruption of a single pathway frequently altered the distribution of non-target polymers. Xylan-related mutants altered not only glucuronoxylan but also HG and, in some cases, xyloglucan, with gux1-1 and gux2-2 producing particularly contrasting GX and HG profiles. By contrast, csla2-1 showed relatively limited secondary effects, whereas gaut10-2 and gaut11-2 showed increased low-molecular-size unesterified HG together with localised redistribution of several hemicellulose epitopes. Esterification mutants separated into distinct redistribution patterns rather than a single shared phenotype. Together, these findings support a directional and asymmetric model of cross-polymer coupling within extractable wall fractions, in which perturbation of HG or GX pathways has broader effects on the wall matrix than disruption of mannan biosynthesis.