Fig. 4

Characterization of polysaccharides in hemicellulose in wild-type (WT) and Bdlsi1-1 plants. a Comprehensive microarray polymer profiling (CoMPP) showing the relative abundance of polysaccharides in a hemicellulose-enriched fraction extracted with sodium hydroxide (NaOH) from the wild-type and the Bdlsi1-1 plants harvested at the ripening stage and at maturity. Results are presented as a heatmap of the average antibody signal intensity, where the white colour corresponds to the lowest intensity and red to the highest. The antibodies that did not show signal for all the samples tested are not included in the heatmap (Additional file 1: Table S1). Concentrations of mixed-linkage glucans (MLG) were determined in the wild-type and the Bdlsi1-1 plants at the ripening growth stage (b) and at maturity (c) using a lichenase-based assay. Data represent the mean (± SD, n ≥ 4) and asterisks indicate significant differences (**p ≤ 0.01; ***p ≤ 0.001) between the wild type and the mutant as assessed by one-way ANOVA followed by the Tukey HDS post hoc test. d Immunostaining of the feruloylated polysaccharides with LM12 mAb and secondary anti-rat antibody (conjugated to Alexa Fluor 488; green channel) was performed on sections of internodes collected at the ripening stage. Images are overlaid with signal of Calcofluor counterstain (blue) outlining the cell walls. Arrowhead indicates stronger LM12 signal in parenchymatic cells of Bdlsi1-1 stems. Scale bars: 50 μm. HG homogalacturonan, RG-I rhamnogalacturonan-I, MLG mixed-linkage glucan, XG xyloglucan, AX arabinoxylan, AGP arabinogalactan protein, GlcA glucuronic acid, FA ferulic acid, HC hemicellulose