Frontiers in Plant Science (Aug 2018)
Functional Analysis of Cellulose Synthase CesA4 and CesA6 Genes in Switchgrass (Panicum virgatum) by Overexpression and RNAi-Mediated Gene Silencing
- Mitra Mazarei,
- Mitra Mazarei,
- Holly L. Baxter,
- Holly L. Baxter,
- Mi Li,
- Mi Li,
- Ajaya K. Biswal,
- Ajaya K. Biswal,
- Keonhee Kim,
- Xianzhi Meng,
- Xianzhi Meng,
- Yunqiao Pu,
- Yunqiao Pu,
- Wegi A. Wuddineh,
- Wegi A. Wuddineh,
- Ji-Yi Zhang,
- Ji-Yi Zhang,
- Geoffrey B. Turner,
- Geoffrey B. Turner,
- Robert W. Sykes,
- Robert W. Sykes,
- Mark F. Davis,
- Mark F. Davis,
- Michael K. Udvardi,
- Michael K. Udvardi,
- Zeng-Yu Wang,
- Zeng-Yu Wang,
- Debra Mohnen,
- Debra Mohnen,
- Arthur J. Ragauskas,
- Arthur J. Ragauskas,
- Arthur J. Ragauskas,
- Nicole Labbé,
- C. Neal Stewart,
- C. Neal Stewart
Affiliations
- Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Mitra Mazarei
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Holly L. Baxter
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Holly L. Baxter
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Mi Li
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Mi Li
- Biosciences Division, Joint Institute for Biological Science, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Ajaya K. Biswal
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Ajaya K. Biswal
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
- Keonhee Kim
- Center for Renewable Carbon, University of Tennessee, Knoxville, Knoxville, TN, United States
- Xianzhi Meng
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Knoxville, TN, United States
- Yunqiao Pu
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Yunqiao Pu
- Biosciences Division, Joint Institute for Biological Science, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Wegi A. Wuddineh
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Wegi A. Wuddineh
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Ji-Yi Zhang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Ji-Yi Zhang
- Noble Research Institute, Ardmore, OK, United States
- Geoffrey B. Turner
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Geoffrey B. Turner
- National Renewable Energy Laboratory, Golden, CO, United States
- Robert W. Sykes
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Robert W. Sykes
- National Renewable Energy Laboratory, Golden, CO, United States
- Mark F. Davis
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Mark F. Davis
- National Renewable Energy Laboratory, Golden, CO, United States
- Michael K. Udvardi
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Michael K. Udvardi
- Noble Research Institute, Ardmore, OK, United States
- Zeng-Yu Wang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Zeng-Yu Wang
- Noble Research Institute, Ardmore, OK, United States
- Debra Mohnen
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Debra Mohnen
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
- Arthur J. Ragauskas
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Arthur J. Ragauskas
- Biosciences Division, Joint Institute for Biological Science, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Arthur J. Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Knoxville, TN, United States
- Nicole Labbé
- Center for Renewable Carbon, University of Tennessee, Knoxville, Knoxville, TN, United States
- C. Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- C. Neal Stewart
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- DOI
- https://doi.org/10.3389/fpls.2018.01114
- Journal volume & issue
-
Vol. 9
Abstract
Switchgrass (Panicum virgatum L.) is a leading lignocellulosic bioenergy feedstock. Cellulose is a major component of the plant cell walls and the primary substrate for saccharification. Accessibility of cellulose to enzymatic breakdown into fermentable sugars is limited by the presence of lignin in the plant cell wall. In this study, putatively novel switchgrass secondary cell wall cellulose synthase PvCesA4 and primary cell wall PvCesA6 genes were identified and their functional role in cellulose synthesis and cell wall composition was examined by overexpression and knockdown of the individual genes in switchgrass. The endogenous expression of PvCesA4 and PvCesA6 genes varied among including roots, leaves, stem, and reproductive tissues. Increasing or decreasing PvCesA4 and PvCesA6 expression to extreme levels in the transgenic lines resulted in decreased biomass production. PvCesA6-overexpressing lines had reduced lignin content and syringyl/guaiacyl lignin monomer ratio accompanied by increased sugar release efficiency, suggesting an impact of PvCesA6 expression levels on lignin biosynthesis. Cellulose content and cellulose crystallinity were decreased, while xylan content was increased in PvCesA4 and PvCesA6 overexpression or knockdown lines. The increase in xylan content suggests that the amount of non-cellulosic cell wall polysaccharide was modified in these plants. Taken together, the results show that the manipulation of the cellulose synthase genes alters the cell wall composition and availability of cellulose as a bioprocessing substrate.
Keywords