Abstract
Cell wall recalcitrance is the major obstacle for plant biomass conversion to biofuels. In this study, we functionally characterized a serine hydroxymethyltransferase (SHMT) from Populus and evaluated its potential for developing lignocellulosic feedstocks. SHMT is an enzyme that plays an important role in cellular one-carbon pathways. However, little is known about its function in plant cell wall-related processes. Among nine SHMT genes in the Populus genome, PtSHMT2 was highly expressed in the developing xylem and was co-expressed with secondary cell wall biosynthetic genes. In Populus transgenic plants overexpressing PdSHMT2, the biomass yield and sugar (glucose and xylose) release were increased whereas the lignin content was decreased. Transcriptomics and metabolomics analyses revealed that genes and metabolites related to secondary cell wall biosynthesis were affected by PdSHMT2 overexpression. Based on the transcription factor binding sites of differentially expressed genes in PdSHMT2 overexpression lines, a total of 27 hub transcription factors were identified. We proposed a regulatory model of action of PdSHMT2 with transcriptional master switches of secondary cell wall biosynthesis. Collectively, these results suggest that PdSHMT2 is a promising candidate for genetic engineering to improve feedstock characteristics to enhance biofuel conversion and reduce the cost of lignocellulosic biofuel production.
Original language | English |
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Pages (from-to) | 195-207 |
Number of pages | 13 |
Journal | Sustainable Energy and Fuels |
Volume | 3 |
Issue number | 1 |
DOIs | |
State | Published - 2019 |
Funding
A special thanks to Clark M. Mindy and Zach L. Zeigler for growing and maintaining plants in ORNL greenhouses. This research was supported by the BioEnergy Science Center (BESC) and the Center for Bioenergy Innovation (CBI). BESC and CBI are supported by the Office of Biological and Environmental Research (BER) in the U.S. Department of Energy Office of Science. Oak Ridge National Laboratory is managed by UT-Battelle, LLC for the U.S. Department of Energy under Contract Number DE-AC05-00OR22725. The work conducted by the U.S. Department of Energy Joint Genome Institute is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. 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).