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de Vries L, MacKay HA, Smith RA, Mottiar Y, Karlen SD, Unda F, Muirragui E, Bingman C, Vander Meulen K, Beebe ET, Fox BG, Ralph J, Mansfield SD. pHBMT1, a BAHD-family monolignol acyltransferase, mediates lignin acylation in poplar. Plant Physiol 2022; 188:1014-1027. [PMID: 34977949 PMCID: PMC8825253 DOI: 10.1093/plphys/kiab546] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/26/2021] [Indexed: 05/13/2023]
Abstract
Poplar (Populus) lignin is naturally acylated with p-hydroxybenzoate ester moieties. However, the enzyme(s) involved in the biosynthesis of the monolignol-p-hydroxybenzoates have remained largely unknown. Here, we performed an in vitro screen of the Populus trichocarpa BAHD acyltransferase superfamily (116 genes) using a wheatgerm cell-free translation system and found five enzymes capable of producing monolignol-p-hydroxybenzoates. We then compared the transcript abundance of the five corresponding genes with p-hydroxybenzoate concentrations using naturally occurring unrelated genotypes of P. trichocarpa and revealed a positive correlation between the expression of p-hydroxybenzoyl-CoA monolig-nol transferase (pHBMT1, Potri.001G448000) and p-hydroxybenzoate levels. To test whether pHBMT1 is responsible for the biosynthesis of monolignol-p-hydroxybenzoates, we overexpressed pHBMT1 in hybrid poplar (Populus alba × P. grandidentata) (35S::pHBMT1 and C4H::pHBMT1). Using three complementary analytical methods, we showed that there was an increase in soluble monolignol-p-hydroxybenzoates and cell-wall-bound monolignol-p-hydroxybenzoates in the poplar transgenics. As these pendent groups are ester-linked, saponification releases p-hydroxybenzoate, a precursor to parabens that are used in pharmaceuticals and cosmetics. This identified gene could therefore be used to engineer lignocellulosic biomass with increased value for emerging biorefinery strategies.
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Affiliation(s)
- Lisanne de Vries
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA
| | - Heather A MacKay
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Rebecca A Smith
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Yaseen Mottiar
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA
| | - Steven D Karlen
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Faride Unda
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA
| | - Emilia Muirragui
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Craig Bingman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Kirk Vander Meulen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Emily T Beebe
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Brian G Fox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - John Ralph
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Shawn D Mansfield
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin 53726, USA
- Author for communication:
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