Alterations in cell-wall glycosyl linkage structure of Arabidopsis murus mutants

Abstract

Methylation (glycosyl-linkage) analyses of the cell walls from Arabidopsis (Arabidopsis thaliana L., Heynh.) murus mutants revealed variations in the linkage structure compared to wild type. Linkage analyses revealed new features for mutations whose defective gene has not been identified. For example, the low-rhamnose mur8 mutant also shows deficiencies in 4-GalA linkages. No change in the 2-Rha to 2,4-Rha ratio indicates the mutant had lower amounts of rhamnogalacturonan I, but no alteration in its fine structure. For all mur mutants, methylation analysis revealed that changes in other polysaccharides occur indirectly as a result of mutation. All mutants were resolved by Principal Components Analyses applied to normalized mole% values for the total set of linkage groups. The 'loadings' responsible for discrimination of mutant and wild type revealed variation in linkage groups otherwise difficult to discern and, in certain instances when the gene is known, resolved the specific deficiency from indirect effects altering other sugar linkage distributions.