Loosening Xyloglucan Accelerates the Enzymatic Degradation of Cellulose in Wood

Mol Plant. 2009 Sep;2(5):904-9. doi: 10.1093/mp/ssp060. Epub 2009 Aug 20.

Abstract

In order to create trees in which cellulose, the most abundant component in biomass, can be enzymatically hydrolyzed highly for the production of bioethanol, we examined the saccharification of xylem from several transgenic poplars, each overexpressing either xyloglucanase, cellulase, xylanase, or galactanase. The level of cellulose degradation achieved by a cellulase preparation was markedly greater in the xylem overexpressing xyloglucanase and much greater in the xylems overexpressing xylanase and cellulase than in the xylem of the wild-type plant. Although a high degree of degradation occurred in all xylems at all loci, the crystalline region of the cellulose microfibrils was highly degraded in the xylem overexpressing xyloglucanase. Since the complex between microfibrils and xyloglucans could be one region that is particularly resistant to cellulose degradation, loosening xyloglucan could facilitate the enzymatic hydrolysis of cellulose in wood.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cellulases / genetics
  • Cellulases / metabolism
  • Cellulose / metabolism*
  • Endo-1,4-beta Xylanases / genetics
  • Endo-1,4-beta Xylanases / metabolism
  • Glucans / metabolism*
  • Glycoside Hydrolases / genetics
  • Glycoside Hydrolases / metabolism
  • Microscopy, Atomic Force
  • Plants, Genetically Modified / enzymology
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / ultrastructure
  • Populus / enzymology
  • Populus / genetics
  • Populus / ultrastructure
  • Wood / metabolism*
  • X-Ray Diffraction
  • Xylans / metabolism*
  • Xylem / enzymology
  • Xylem / ultrastructure
  • beta-Galactosidase / genetics
  • beta-Galactosidase / metabolism

Substances

  • Glucans
  • Xylans
  • xyloglucan
  • Cellulose
  • Cellulases
  • Glycoside Hydrolases
  • xyloglucan endo(1-4)-beta-D-glucanase
  • beta-Galactosidase
  • Endo-1,4-beta Xylanases