Knock-Down of Galacturonosyltransferase-4 Gene Leads to Reduction in Lignin-Carbohydrate Crosslinking in Switchgrass

The Science

Investigate downregulation of a pectin biosynthetic gene, GAUT4, on the structures of lignin and their importance to the recalcitrance of switchgrass.

The Impact

  • GAUT4-KD lines have a lower abundance of ferulate and lignin-carbohydrate complex cross-linkages, reduced hemicellulose molecular weights, and reduced amounts of residual arabinan and xylan in lignin-enriched fractions, in comparison to the wildtype (WT).
  • These structural changes in lignin and hemicellulose lead to a greater coalescence and migration of lignin after hydrothermal pretreatment. The results reveal the roles of both decreased lignin-polymer and pectin cross-links in the reduction of recalcitrance in GAUT4-KD switchgrass.


Chromatographic and NMR analyses of the molecular structure of lignin and hemicellulose as well as the level of lignin-carbohydrate crosslinking in GAUT4-downregulated switchgrass.

Principal Investigator(s)

Mi Li
Oak Ridge National Laboratory


Li, M. et al. “Downregulation of pectin biosynthesis gene GAUT4 leads to reduced ferulate and lignin-carbohydrate cross-linking in switchgrass.” Communications Biology 2, 22 (2019). [DOI:10.1038/s42003-018-0265-6]