Title

Functional Analysis of Cellulose Synthase CesA4 and CesA6 Genes in Switchgrass (Panicum virgatum) by Overexpression and RNAi-Mediated Gene Silencing

Source Publication (e.g., journal title)

Frontiers in Plant Science

Authors

Mitra Mazarei, University of Tennessee, Knoxville, Oak Ridge National LaboratoryFollow
Holly L. Baxter, University of Tennessee, Knoxville, Oak Ridge National LaboratoryFollow
Mi Li, Oak Ridge National Laboratory
Ajaya K. Biswal, Oak Ridge National Laboratory, University of Georgia, Athens
Keonhee Kim, University of Tennessee, KnoxvilleFollow
Xianzhi Meng, University of Tennessee, Knoxville, Oak Ridge National Laboratory
Yunqiao Pu, Oak Ridge National Laboratory
Wegi A. Wuddineh, University of Tennessee, Knoxville, Oak Ridge National Laboratory
Ji-Yi Zhang, Oak Ridge National Laboratory, Noble Research Institute
Geoffrey B. Turner, Oak Ridge National Laboratory, National Renewable Energy Laboratory
Robert W. Sykes, Oak Ridge National Laboratory, National Renewable Energy Laboratory
Mark F. Davis, Oak Ridge National Laboratory, National Renewable Energy Laboratory
Michael K. Udvardi, Oak Ridge National Laboratory, Noble Research Institute
Zeng-Yu Wang, Oak Ridge National Laboratory, Noble Research Institute
Debra Mohnen, Oak Ridge National Laboratory, University of Georgia, Athens
Arthur J. Ragauskas, University of Tennessee, Knoxville, Oak Ridge National Laboratory
Nicole Labbé, University of Tennessee, Knoxville
C. Neal Stewart Jr., University of Tennessee, Knoxville, Oak Ridge National LaboratoryFollow

Document Type

Article

Publication Date

8-3-2018

DOI

10.3389/fpls.2018.01114

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.

Comments

This article was published openly thanks to the University of Tennessee Open Publishing Support Fund.

Licensed under a Creative Commons Attribution 4.0 International license.

Recommended Citation

Mazarei M, Baxter HL, Li M, Biswal AK, Kim K, Meng X, Pu Y, Wuddineh WA, Zhang J-Y, Turner GB, Sykes RW, Davis MF, Udvardi MK, Wang Z-Y, Mohnen D, Ragauskas AJ, Labbé N and Stewart CN Jr. (2018) Functional Analysis of Cellulose Synthase CesA4 and CesA6 Genes in Switchgrass (Panicum virgatum) by Overexpression and RNAi-Mediated Gene Silencing. Frontiers in Plant Sci. 9:1114. doi: 10.3389/fpls.2018.01114

Submission Type

Publisher's Version