Figure 5.

The uuat1-2 Mutant Shows Increased Pectin Methylesterification and Has Reduced Pectin Methylesterase Activity in Seeds.

(A) and (B) Labeling of highly methylesterified HG in the adherent mucilage from seeds of wild-type Col-0 (A) and the uuat1-2 mutant line (B) imaged using confocal microscopy optical section reconstruction of AM released from imbibed seeds. The LM20 antibody (green) was used to label HG domains, and propidium iodide was used to stain the seed coat surface (pink). Bars = 100 μm.

(C) and (D) Appearance of seed adherent mucilage from wild-type Col-0 (C) and uuat1-2 (D) in the presence of a cation chelator. Seeds were stained with ruthenium red after 1 h of imbibition in 0.5 M EDTA. Bars = 100 μm.

(E) Degree of methylesterification in wild-type Col-0 and uuat1-2 in seed+AM and the soluble mucilage fractions. Error bars represent se (n = 16, from three biological replicates). ANOVA and Tukey tests were performed and compared with wild-type Col-0 (*P < 0.05).

(F) Seed PME activity. Total protein extracts from mature dry seeds of wild-type Col-0 and uuat1-2 were used to measure PME activity. The PME activity was normalized to the average wild-type activity (100). Error bars represent se (n = 16 for SM and n = 12 for seed+AM from three biological replicates).