Abstract
Knockdown (KD) expression of GAlactUronosylTransferase 4 (GAUT4) in switchgrass improves sugar yield and ethanol production from the biomass. The reduced recalcitrance of GAUT4-KD transgenic biomass is associated with reduced cell wall pectic homogalacturonan and rhamnogalacturonan II content and cross-linking, and the associated increases in accessibility of cellulose to enzymatic deconstruction. To further probe the molecular basis for the reduced recalcitrance of GAUT4-KD biomass, potential recalcitrance-related factors including the physicochemical properties of lignin and hemicellulose are investigated. We show that the transgenic switchgrass have a lower abundance of ferulate and lignin-carbohydrate complex cross-linkages, reduced amounts of residual arabinan and xylan in lignin-enriched fractions after enzymatic hydrolysis, and greater coalescence and migration of lignin after hydrothermal pretreatment in comparison to the wild-type switchgrass control. The results reveal the roles of both decreased lignin-polymer and pectin cross-links in the reduction of recalcitrance in PvGAUT4-KD switchgrass.
| Original language | English |
|---|---|
| Article number | 22 |
| Journal | Communications Biology |
| Volume | 2 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2019 |
Funding
This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory (ORNL), which is managed by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. This study was supported and performed as part of the BioEnergy Science Center (BESC) and the Center for Bioenergy Innovation (CBI). The BESC and CBI are US Department of Energy Bioenergy Research Centers supported by the Office of Biological and Environmental Research in the DOE Office of Science. The research was also partially funded by the Department of Energy funded Center for Plant and Microbial Complex Carbohydrates grant DESC0015662 (DE-FG02-93ER20097). The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.
| Funders | Funder number |
|---|---|
| BioEnergy Science Center | |
| DOE Office of Science | |
| Department of Energy funded Center for Plant and Microbial Complex Carbohydrates | DE-FG02-93ER20097, DESC0015662 |
| Office of Biological and Environmental Research | |
| US Department of Energy | |
| Biological and Environmental Research | DE-AC05-00OR22725 |
| Oak Ridge National Laboratory | |
| Center for Bioenergy Innovation |
