Title: Identification of functional single nucleotide polymorphism of Populus trichocarpa PtrEPSP‐TF and determination of its transcriptional effect

Abstract

In plants, the phenylpropanoid pathway is responsible for the synthesis of a diverse array of secondary metabolites that include lignin monomers, flavonoids, and coumarins, many of which are essential for plant structure, biomass recalcitrance, stress defense, and nutritional quality. Our previous studies have demonstrated that Populus trichocarpa PtrEPSP-TF, an isoform of 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, has transcriptional activity and regulates phenylpropanoid biosynthesis in Populus. In this study, we report the identification of single nucleotide polymorphism (SNP) of PtrEPSP-TF that defines its functionality. Populus natural variants carrying this SNP were shown to have reduced lignin content. Here, we demonstrated that the SNP-induced substitution of 142nd amino acid (PtrEPSP-TF^D142E) dramatically impairs the DNA-binding and transcriptional activity of PtrEPSP-TF. When introduced to a monocot species rice (Oryza sativa) in which an EPSP synthase isoform with the DNA-binding helix-turn-helix (HTH) motif is absent, the PtrEPSP-TF, but not PtrEPSP-TF^D142E, activated genes in the phenylpropanoid pathway. More importantly, heterologous expression of PtrEPSP-TF uncovered five new transcriptional regulators of phenylpropanoid biosynthesis in rice. Collectively, this study identifies the key amino acid required for PtrEPSP-TF functionality and provides a strategy to uncover new transcriptional regulators in phenylpropanoid biosynthesis.

Authors:

Xie, Meng ^[1]; Zhang, Jin ^[2]; Singan, Vasanth R. ^[3]; McGranahan, Melissa J. ^[4]; LaFayette, Peter R. ^[4]; Jawdy, Sara S. ^[2]; Engle, Nancy ^[2]; Doeppke, Crissa ^[5]; Tschaplinski, Timothy J. ^[2]; Davis, Mark F. ^[5]; Lindquist, Erika ^[3]; Barry, Kerrie ^[3]; Schmutz, Jeremy ^[6]; Parrott, Wayne A. ^[4]; Chen, Feng ^[7]; Tuskan, Gerald A. ^[2]; Chen, Jin‐Gui ^[2]; Muchero, Wellington ^[2]

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+ Show Author Affiliations

1. Center for Bioenergy Innovation Oak Ridge National Laboratory Oak Ridge TN USA, Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA, Department of Plant Sciences University of Tennessee Knoxville TN USA
2. Center for Bioenergy Innovation Oak Ridge National Laboratory Oak Ridge TN USA, Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
3. U.S. Department of Energy Joint Genome Institute Walnut Creek CA USA
4. Department of Crop and Soil Sciences University of Georgia Athens GA USA
5. Center for Bioenergy Innovation Oak Ridge National Laboratory Oak Ridge TN USA, National Renewable Energy Laboratory Golden CO USA
6. U.S. Department of Energy Joint Genome Institute Walnut Creek CA USA, HudsonAlpha Institute for Biotechnology Huntsville AL USA
7. Department of Plant Sciences University of Tennessee Knoxville TN USA

Publication Date:

Fri Jan 03 00:00:00 EST 2020

Research Org.:

National Renewable Energy Laboratory (NREL), Golden, CO (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division

OSTI Identifier:

1671138

Alternate Identifier(s):

OSTI ID: 1593683; OSTI ID: 1648976

Report Number(s):

NREL/JA-2700-75861
Journal ID: ISSN 2475-4455; e00178

Grant/Contract Number:  

AC36-08GO28308; AC05‐00OR22725; AC02‐05CH11231

Resource Type:

Published Article

Journal Name:

Plant Direct

Additional Journal Information:

Journal Name: Plant Direct Journal Volume: 4 Journal Issue: 1; Journal ID: ISSN 2475-4455

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

United Kingdom

Language:

English

Subject:

09 BIOMASS FUELS; 59 BASIC BIOLOGICAL SCIENCES; DNA binding; EPSP synthase; phenylpropanoid; rice; transcriptional regulation