Fig. 8: Schematic representation of R. delemar cell wall organization.
Illustrative summaries are presented for (a) apo and (b) nikkomycin-treated R. delemar samples. Cell wall thickness has increased from approximately 120 nm to 210 nm. Chitin, organized as rigid fibrillar domains, is deposited external to the plasma membrane, featuring an antiparallel chain arrangement. These fibrils exhibit a substantial degree of deacetylation, resulting in a significant presence of chitosan, which plays a vital role in maintaining the hydration and dynamics of the rigid portion of the cell wall. Some β-glucans (B; cyan) are covalently bonded to chitin and chitosan, especially their type-c allomorphs (Chc and Csc). This polysaccharide complex will be depleted by nikkomycin treatment. Chitin, chitosan, and β-glucans also contribute to the soft and hydrated matrix, which also includes polymers such as mannan, polyfucose, and heteroglycans containing Gal and its amino sugar derivatives. Molecular fractions are considered, although the depicted scheme may not be strictly to scale. The background is colored to show the water gradient within the cell wall.
