Silencing Folylpolyglutamate Synthetase1 (FPGS1) in Switchgrass (Panicum virgatum L.) Improves Lignocellulosic Biofuel Production

Frontiers in Plant Science

卷:11

Holly L. Baxter¹  Miguel Rodriguez²  Brian H. Davison²  Jace M. Natzke²  Alexandru Dumitrache²  Geoffrey B. Turner⁴  Robert W. Sykes⁴  Mark F. Davis⁴  Zeng-Yu Wang⁵  Hongli Xie⁵  Guifen Li⁵  Michael K. Udvardi⁵  Ji-Yi Zhang⁵  Elison B. Blancaflor⁵  Avinash Srivastava⁵  Yuhong Tang⁵  Charles Neal Stewart⁶  Mitra Mazarei⁶ 

[1] BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States;

[2] Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States;

[3] Department of Plant Sciences, The University of Tennessee, Knoxville, TN, United States;

[4] National Renewable Energy Laboratory, Golden, CO, United States;

[5] Noble Research Institute, Ardmore, OK, United States;

[6] The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States;

关键词: folylpolyglutamate synthetase;    switchgrass;    RNAi-gene silencing;    PvFPGS1;    lignocellulosic;    biofuel;   

DOI  :  10.3389/fpls.2020.00843

来源: DOAJ

【 摘 要 】

Switchgrass (Panicum virgatum L.) is a lignocellulosic perennial grass with great potential in bioenergy field. Lignocellulosic bioenergy crops are mostly resistant to cell wall deconstruction, and therefore yield suboptimal levels of biofuel. The one-carbon pathway (also known as C1 metabolism) is critical for polymer methylation, including that of lignin and hemicelluloses in cell walls. Folylpolyglutamate synthetase (FPGS) catalyzes a biochemical reaction that leads to the formation of folylpolyglutamate, an important cofactor for many enzymes in the C1 pathway. In this study, the putatively novel switchgrass PvFPGS1 gene was identified and its functional role in cell wall composition and biofuel production was examined by RNAi knockdown analysis. The PvFPGS1-downregulated plants were analyzed in the field over three growing seasons. Transgenic plants with the highest reduction in PvFPGS1 expression grew slower and produced lower end-of-season biomass. Transgenic plants with low-to-moderate reduction in PvFPGS1 transcript levels produced equivalent biomass as controls. There were no significant differences observed for lignin content and syringyl/guaiacyl lignin monomer ratio in the low-to-moderately reduced PvFPGS1 transgenic lines compared with the controls. Similarly, sugar release efficiency was also not significantly different in these transgenic lines compared with the control lines. However, transgenic plants produced up to 18% more ethanol while maintaining congruent growth and biomass as non-transgenic controls. Severity of rust disease among transgenic and control lines were not different during the time course of the field experiments. Altogether, the unchanged lignin content and composition in the low-to-moderate PvFPGS1-downregulated lines may suggest that partial downregulation of PvFPGS1 expression did not impact lignin biosynthesis in switchgrass. In conclusion, the manipulation of PvFPGS1 expression in bioenergy crops may be useful to increase biofuel potential with no growth penalty or increased susceptibility to rust in feedstock.

【 授权许可】

Unknown