Cutin, the structural component of plant cuticle, is a biopolyester composed of hydroxy- and hydroxyepoxy-fatty acids The major monomers are a 16-hydroxy C16 acid, a 10,16-dihydroxy C16 acid toget

Biochemistry and function of cutin and suberin

https://spbftu.ru/site/upload/201511041948_Shorohova_Kapitsa_decomp_2014.pdf

Influence of the substrate and ecosystem attributes on the decomposition rates of coarse woody debris in European boreal forests

In 1665, Robert Hooke was examining suberized cork cells from the bark of Quercus suber when he gave the first description of a cell. Von Hohnel was also examining cork cells from Q. suber more than 200 years later when he described the lamellar structure characteristic of suberin (466). It has become quite clear that suberized walls contain an insoluble polymeric material called suberin, which is associated with a complex mixture of nonpolar compounds collectively called waxes. Electron microscopic examination of suberized walls usually reveals a lamellar structure in which the light and dark bands are probably composed of the soluble waxes and the polymer, respectively. Since suberin is laid down as an insoluble polymer in the cell wall it is not possible to isolate suberin as a pure polymer. It can be isolated only as a suberin-enriched wall fraction containing about 50% cell wall carbohydrate material. The insolubility of this material and the complexity of its structure and composition make chemical and biochemical studies of suberin extremely difficult. From the limited number of studies conducted so far we have some knowledge about the location, composition, structure, biosynthesis, biodegradation, and function of suberized cell walls.

Chemistry, Biochemistry, and Function of Suberin and Associated Waxes

https://www.ucd.ie/cforrep/library/workreports/climfo/Decomp%20of%20stumps%20vs%20burning%20Shorohova%20et%20al%202008.pdf

Decomposition of stumps in a chronosequence after clear-felling vs. clear-felling with prescribed burning in a southern boreal forest in Finland

Fusarium solani pisi isolate T-8 was found to grow with suberin from potato tuber periderm as the sole source of carbon. The extracellular fluid from such cultures catalysed the hydrolysis of p-nitrophenyl butyrate and radioactive apple cutin. The major portion of this esterase was bound to the suberin-containing mycelial mat from which the activity could be washed out with a 0·4% Triton X-100 solution. All of this esterase activity was contained in two isozymes which were purified by a passage of the Triton wash through QAE-Sephadex followed by ion exchange chromatography with SP-Sephadex. Both isozymes were homogeneous as judged by polyacrylamide gel electrophoresis with or without SDS. Each showed a molecular weight of 23 000. Analysis of the aliphatic components released by the esterase from suberin by combined GLC/MS showed that all classes of monomers were released by the esterase. The two enzymes were very similar in their catalytic properties and amino acid composition to two isozymes of cutinase isolated from the extracellular fluid of the same fungus grown on apple cutin. The esterases had one disulphide bridge and no free SH group just as previously noted for fungal cutinases. Ouchterlony double diffusion analyses showed that the two esterases isolated from suberin-grown cells cross-reacted with complete fusion of the precipitin lines when tested with antibodies generated against the two cutinases generated by cutin-grown cells. These results strongly suggest that F. solani pisi generates extremely similar, if not identical, polyesterases to degrade cutin and suberin when these polymers constitute the sole carbon source.

Suberin-Grown Fusarium-Solani F-Sp Pisi Generates a Cutinase-Like Esterase Which Depolymerizes the Aliphatic Components of Suberin

The degradation of beech bark by three wood-decaying fungi has been analyzed at the ultra-structural level and the micromorphological changes occurring in the walls of the diverse cell types compared with the decay pattern in wood cells.

W. Liese

Papers

Ultrastructural aspects of beech bark degradation by fungi