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Behar H, Mottiar Y, Chandrasekhar R, Grappadelli AC, Pauly M, Samuels AL, Mansfield SD, Brumer H. Populus endo-glucanase 16 localizes to the cell walls of developing tissues. Plant Direct 2023; 7:e482. [PMID: 36733272 PMCID: PMC9887094 DOI: 10.1002/pld3.482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
The hemicelluloses comprise a group of matrix glycans that interact with cellulose microfibrils in plant cell walls and play important roles in establishing wall architecture. The structures of hemicelluloses are determined by carbohydrate-active enzymes (CAZymes) that synthesize, integrate, and break down these polymers. Specifically, endo-glucanase 16 (EG16) enzymes, which are related to the well-known xyloglucan endotransglycosylase/hydrolase (XTH) gene products in Glycoside Hydrolase Family 16 (GH16), have been implicated in the degradation of the β(1,4)-linked backbone of mixed-linkage β(1,3);β(1,4)-glucans (MLG) and xyloglucans. EG16 members are single-copy genes found in most plant clades but are absent from many eudicots, including the model plant Arabidopsis thaliana. Until recently, EG16 members had only been characterized in vitro, establishing their substrate specificity, protein structure, and phylogenetic history, but their biological function was unknown. Here we used a hybrid polar, Populus alba × Populus grandidentata (P39), as a model to examine EG16 expression, subcellular localization, and pheno- and chemotypes of EG16-downregulated P39 plants. Populus EG16 expression is strong in young tissues, but RNAi-mediated downregulation did not impact plant growth nor the fine structure of the hemicellulose xyloglucan, suggesting a restricted or currently unknown role in angiosperm physiology.
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Affiliation(s)
- Hila Behar
- Michael Smith LaboratoriesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of Biochemistry and Molecular BiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Yaseen Mottiar
- Department of Wood ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Rohan Chandrasekhar
- Department of Wood ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | | | - Markus Pauly
- Institute for Plant Cell Biology and BiotechnologyHeinrich Heine UniversityDüsseldorfGermany
| | - A. Lacey Samuels
- Department of BotanyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of BotanyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Harry Brumer
- Michael Smith LaboratoriesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of Biochemistry and Molecular BiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of BotanyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of ChemistryUniversity of British ColumbiaVancouverBritish ColumbiaCanada
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2
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Mottiar Y, Smith RA, Karlen SD, Ralph J, Mansfield SD. Evolution of p-coumaroylated lignin in eudicots provides new tools for cell wall engineering. New Phytol 2023; 237:251-264. [PMID: 36196006 PMCID: PMC10099755 DOI: 10.1111/nph.18518] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Ester-linked p-coumarate (pCA) is a hallmark feature of the secondary cell walls in commelinid monocot plants. It has been shown that pCA groups arise during lignin polymerisation from the participation of monolignol conjugates assembled by p-coumaroyl-CoA:monolignol transferase (PMT) enzymes, members of the BAHD superfamily of acyltransferases. Herein, we report that a eudicot species, kenaf (Hibiscus cannabinus), naturally contains p-coumaroylated lignin in the core tissues of the stems but not in the bast fibres. Moreover, we identified a novel acyltransferase, HcPMT, that shares <30% amino acid identity with known monocot PMT sequences. Recombinant HcPMT showed a preference in enzyme assays for p-coumaroyl-CoA and benzoyl-CoA as acyl donor substrates and sinapyl alcohol as an acyl acceptor. Heterologous expression of HcPMT in hybrid poplar trees led to the incorporation of pCA in lignin, but no improvement in the saccharification potential of the wood. This work illustrates the value in mining diverse plant taxa for new monolignol acyltransferases. Furthermore, the occurrence of pCA outside monocot lineages may represent another example of convergent evolution in lignin structure. This discovery expands textbook views on cell wall biochemistry and provides a new molecular tool for engineering the lignin of biomass feedstock plants.
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Affiliation(s)
- Yaseen Mottiar
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
- Department of Energy Great Lakes Bioenergy Research CenterUniversity of Wisconsin1552 University AvenueMadisonWI53726USA
| | - Rebecca A. Smith
- Department of Energy Great Lakes Bioenergy Research CenterUniversity of Wisconsin1552 University AvenueMadisonWI53726USA
- Department of BiochemistryUniversity of Wisconsin433 Babcock DriveMadisonWI53706USA
| | - Steven D. Karlen
- Department of Energy Great Lakes Bioenergy Research CenterUniversity of Wisconsin1552 University AvenueMadisonWI53726USA
- Department of BiochemistryUniversity of Wisconsin433 Babcock DriveMadisonWI53706USA
| | - John Ralph
- Department of Energy Great Lakes Bioenergy Research CenterUniversity of Wisconsin1552 University AvenueMadisonWI53726USA
- Department of BiochemistryUniversity of Wisconsin433 Babcock DriveMadisonWI53706USA
| | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
- Department of Energy Great Lakes Bioenergy Research CenterUniversity of Wisconsin1552 University AvenueMadisonWI53726USA
- Department of BotanyUniversity of British Columbia6270 University BoulevardVancouverBCV6T 1Z4Canada
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Mottiar Y, Karlen SD, Goacher RE, Ralph J, Mansfield SD. Metabolic engineering of p-hydroxybenzoate in poplar lignin. Plant Biotechnol J 2023; 21:176-188. [PMID: 36161690 PMCID: PMC9829402 DOI: 10.1111/pbi.13935] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 08/10/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Ester-linked p-hydroxybenzoate occurs naturally in poplar lignin as pendent groups that can be released by mild alkaline hydrolysis. These 'clip-off' phenolics can be separated from biomass and upgraded into diverse high-value bioproducts. We introduced a bacterial chorismate pyruvate lyase gene into transgenic poplar trees with the aim of producing more p-hydroxybenzoate from chorismate, itself a metabolic precursor to lignin. By driving heterologous expression specifically in the plastids of cells undergoing secondary wall formation, this strategy achieved a 50% increase in cell-wall-bound p-hydroxybenzoate in mature wood and nearly 10 times more in developing xylem relative to control trees. Comparable amounts also remained as soluble p-hydroxybenzoate-containing xylem metabolites, pointing to even greater engineering potential. Mass spectrometry imaging showed that the elevated p-hydroxybenzoylation was largely restricted to the cell walls of fibres. Finally, transgenic lines outperformed control trees in assays of saccharification potential. This study highlights the biotech potential of cell-wall-bound phenolate esters and demonstrates the importance of substrate supply in lignin engineering.
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Affiliation(s)
- Yaseen Mottiar
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
- Department of Energy Great Lakes Bioenergy Research CenterMadisonWIUSA
| | - Steven D. Karlen
- Department of Energy Great Lakes Bioenergy Research CenterMadisonWIUSA
| | - Robyn E. Goacher
- Department of Biochemistry, Chemistry, and PhysicsNiagara UniversityNorth TonawandaNYUSA
| | - John Ralph
- Department of Energy Great Lakes Bioenergy Research CenterMadisonWIUSA
- Department of BiochemistryUniversity of WisconsinMadisonWIUSA
| | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
- Department of Energy Great Lakes Bioenergy Research CenterMadisonWIUSA
- Department of BotanyUniversity of British ColumbiaVancouverBCCanada
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Unda F, Mottiar Y, Mahon EL, Karlen SD, Kim KH, Loqué D, Eudes A, Ralph J, Mansfield SD. A new approach to zip-lignin: 3,4-dihydroxybenzoate is compatible with lignification. New Phytol 2022; 235:234-246. [PMID: 35377486 PMCID: PMC9325543 DOI: 10.1111/nph.18136] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 03/17/2022] [Indexed: 06/02/2023]
Abstract
Renewed interests in the development of bioenergy, biochemicals, and biomaterials have elicited new strategies for engineering the lignin of biomass feedstock plants. This study shows, for the first time, that 3,4-dihydroxybenzoate (DHB) is compatible with the radical coupling reactions that assemble polymeric lignin in plants. We introduced a bacterial 3-dehydroshikimate dehydratase into hybrid poplar (Populus alba × grandidentata) to divert carbon flux away from the shikimate pathway, which lies upstream of lignin biosynthesis. Transgenic poplar wood had up to 33% less lignin with p-hydroxyphenyl units comprising as much as 10% of the lignin. Mild alkaline hydrolysis of transgenic wood released fewer ester-linked p-hydroxybenzoate groups than control trees, and revealed the novel incorporation of cell-wall-bound DHB, as well as glycosides of 3,4-dihydroxybenzoic acid (DHBA). Two-dimensional nuclear magnetic resonance (2D-NMR) analysis uncovered DHBA-derived benzodioxane structures suggesting that DHB moieties were integrated into the lignin polymer backbone. In addition, up to 40% more glucose was released from transgenic wood following ionic liquid pretreatment and enzymatic hydrolysis. This work highlights the potential of diverting carbon flux from the shikimate pathway for lignin engineering and describes a new type of 'zip-lignin' derived from the incorporation of DHB into poplar lignin.
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Affiliation(s)
- Faride Unda
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
- Department of EnergyGreat Lakes Bioenergy Research CenterWisconsin Energy InstituteUniversity of Wisconsin‐Madison1552 University AvenueMadisonWI53726USA
| | - Yaseen Mottiar
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
- Department of EnergyGreat Lakes Bioenergy Research CenterWisconsin Energy InstituteUniversity of Wisconsin‐Madison1552 University AvenueMadisonWI53726USA
| | - Elizabeth L. Mahon
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
- Department of EnergyGreat Lakes Bioenergy Research CenterWisconsin Energy InstituteUniversity of Wisconsin‐Madison1552 University AvenueMadisonWI53726USA
| | - Steven D. Karlen
- Department of EnergyGreat Lakes Bioenergy Research CenterWisconsin Energy InstituteUniversity of Wisconsin‐Madison1552 University AvenueMadisonWI53726USA
- Department of BiochemistryUniversity of Wisconsin‐Madison433 Babcock DriveMadisonWI53706USA
| | - Kwang Ho Kim
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
- Clean Energy Research CenterKorea Institute of Science and TechnologySeoul02792Korea
| | - Dominique Loqué
- Joint BioEnergy Institute5885 Hollis StreetEmeryvilleCA94608USA
| | - Aymerick Eudes
- Joint BioEnergy Institute5885 Hollis StreetEmeryvilleCA94608USA
- Environmental Genomics and Systems Biology DivisionLawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - John Ralph
- Department of EnergyGreat Lakes Bioenergy Research CenterWisconsin Energy InstituteUniversity of Wisconsin‐Madison1552 University AvenueMadisonWI53726USA
- Department of BiochemistryUniversity of Wisconsin‐Madison433 Babcock DriveMadisonWI53706USA
| | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
- Department of EnergyGreat Lakes Bioenergy Research CenterWisconsin Energy InstituteUniversity of Wisconsin‐Madison1552 University AvenueMadisonWI53726USA
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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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6
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Mottiar Y, Mansfield SD. Lignin p-Hydroxybenzoylation Is Negatively Correlated With Syringyl Units in Poplar. Front Plant Sci 2022; 13:938083. [PMID: 35937345 PMCID: PMC9355280 DOI: 10.3389/fpls.2022.938083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/13/2022] [Indexed: 05/15/2023]
Abstract
The lignin found in the cell walls of poplar fibres is decorated with ester-linked p-hydroxybenzoate moieties that originate from the participation of acylated monolignols in lignin polymerisation. Although little is known about the biological implications of these cell-wall constituents, it has historically been postulated that acylated monolignols might promote lignification in syringyl lignin-rich species such as poplar. However, cell-wall-bound p-hydroxybenzoate groups were negatively correlated with syringyl units in a collection of 316 unrelated genotypes of black cottonwood (Populus trichocarpa). Based upon this observation, several alternative hypotheses on the occurrence of lignin acylation are presented.
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7
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Mottiar Y, Gierlinger N, Jeremic D, Master ER, Mansfield SD. Atypical lignification in eastern leatherwood (Dirca palustris). New Phytol 2020; 226:704-713. [PMID: 31883117 PMCID: PMC7187453 DOI: 10.1111/nph.16394] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 12/11/2019] [Indexed: 05/30/2023]
Abstract
Lignin is a complex phenolic biopolymer found mainly in the secondary cell walls of vascular plants, where it contributes to mechanical strength, water conduction, and plant defence. We studied the lignin of eastern leatherwood (Dirca palustris) because this slow-growing woody shrub is known for its flexible stems. Various analytical techniques and microscopy methods were employed to examine the composition and distribution of lignin and structural polysaccharides in leatherwood xylem in comparison with trembling aspen (Populus tremuloides) and white spruce (Picea glauca). We found that leatherwood has low overall levels of lignin, a high syringyl lignin content, and a unique distribution of lignin. Most remarkably, the cell corners and middle lamellae remain unlignified in mature xylem. These findings help explain the flexibility of leatherwood and also call into question the classical model of lignification, which purports that lignin polymerization begins in the cell corners and middle lamellae. This atypical lignification regime vividly illustrates the diversity in plant secondary cell wall formation that abounds in nature and casts leatherwood as a new model for the study of lignin biogenesis.
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Affiliation(s)
- Yaseen Mottiar
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
| | - Notburga Gierlinger
- Department of NanobiotechnologyInstitute for BiophysicsUniversity of Natural Resources and Life Sciences ViennaMuthgasse 11Vienna1190Austria
| | - Dragica Jeremic
- Department of Sustainable BioproductsMississippi State UniversityBox 9680StarkvilleMS39759USA
| | - Emma R. Master
- Department of Chemical Engineering & Applied ChemistryUniversity of Toronto200 College StreetTorontoONM5S 3E5Canada
| | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British Columbia2424 Main MallVancouverBCV6T 1Z4Canada
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Kuglerová L, García L, Pardo I, Mottiar Y, Richardson JS. Does leaf litter from invasive plants contribute the same support of a stream ecosystem function as native vegetation? Ecosphere 2017. [DOI: 10.1002/ecs2.1779] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Lenka Kuglerová
- Department of Forest and Conservation Sciences University of British Columbia Vancouver British Columbia V6T 1Z4 Canada
| | - Liliana García
- Departamento de Ecología y Biología Animal Universidad de Vigo Campus As Lagoas – Marcosende 36310 Vigo Spain
| | - Isabel Pardo
- Departamento de Ecología y Biología Animal Universidad de Vigo Campus As Lagoas – Marcosende 36310 Vigo Spain
| | - Yaseen Mottiar
- Department of Wood Science University of British Columbia Vancouver British Columbia V6T 1Z4 Canada
| | - John S. Richardson
- Department of Forest and Conservation Sciences University of British Columbia Vancouver British Columbia V6T 1Z4 Canada
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Mottiar Y, Vanholme R, Boerjan W, Ralph J, Mansfield SD. Designer lignins: harnessing the plasticity of lignification. Curr Opin Biotechnol 2016; 37:190-200. [DOI: 10.1016/j.copbio.2015.10.009] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/14/2015] [Accepted: 10/26/2015] [Indexed: 12/20/2022]
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Cass CL, Peraldi A, Dowd PF, Mottiar Y, Santoro N, Karlen SD, Bukhman YV, Foster CE, Thrower N, Bruno LC, Moskvin OV, Johnson ET, Willhoit ME, Phutane M, Ralph J, Mansfield SD, Nicholson P, Sedbrook JC. Effects of PHENYLALANINE AMMONIA LYASE (PAL) knockdown on cell wall composition, biomass digestibility, and biotic and abiotic stress responses in Brachypodium. J Exp Bot 2015; 66:4317-35. [PMID: 26093023 PMCID: PMC4493789 DOI: 10.1093/jxb/erv269] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The phenylpropanoid pathway in plants synthesizes a variety of structural and defence compounds, and is an important target in efforts to reduce cell wall lignin for improved biomass conversion to biofuels. Little is known concerning the trade-offs in grasses when perturbing the function of the first gene family in the pathway, PHENYLALANINE AMMONIA LYASE (PAL). Therefore, PAL isoforms in the model grass Brachypodium distachyon were targeted, by RNA interference (RNAi), and large reductions (up to 85%) in stem tissue transcript abundance for two of the eight putative BdPAL genes were identified. The cell walls of stems of BdPAL-knockdown plants had reductions of 43% in lignin and 57% in cell wall-bound ferulate, and a nearly 2-fold increase in the amounts of polysaccharide-derived carbohydrates released by thermochemical and hydrolytic enzymic partial digestion. PAL-knockdown plants exhibited delayed development and reduced root growth, along with increased susceptibilities to the fungal pathogens Fusarium culmorum and Magnaporthe oryzae. Surprisingly, these plants generally had wild-type (WT) resistances to caterpillar herbivory, drought, and ultraviolet light. RNA sequencing analyses revealed that the expression of genes associated with stress responses including ethylene biosynthesis and signalling were significantly altered in PAL knocked-down plants under non-challenging conditions. These data reveal that, although an attenuation of the phenylpropanoid pathway increases carbohydrate availability for biofuel, it can adversely affect plant growth and disease resistance to fungal pathogens. The data identify notable differences between the stress responses of these monocot pal mutants versus Arabidopsis (a dicot) pal mutants and provide insights into the challenges that may arise when deploying phenylpropanoid pathway-altered bioenergy crops.
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Affiliation(s)
- Cynthia L Cass
- School of Biological Sciences, Illinois State University, Normal, IL 61790 USA US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA
| | - Antoine Peraldi
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Patrick F Dowd
- USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Crop Bioprotection Research Unit, Peoria, IL 61604, USA
| | - Yaseen Mottiar
- US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA Department of Wood Science, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Nicholas Santoro
- US Department of Energy Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA
| | - Steven D Karlen
- US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA
| | - Yury V Bukhman
- US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA
| | - Cliff E Foster
- US Department of Energy Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA
| | - Nick Thrower
- US Department of Energy Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA
| | - Laura C Bruno
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Oleg V Moskvin
- US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA
| | - Eric T Johnson
- USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Crop Bioprotection Research Unit, Peoria, IL 61604, USA
| | - Megan E Willhoit
- School of Biological Sciences, Illinois State University, Normal, IL 61790 USA US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA
| | - Megha Phutane
- School of Biological Sciences, Illinois State University, Normal, IL 61790 USA US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA
| | - John Ralph
- US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA Department of Biochemistry, Wisconsin Energy Institute, University of Wisconsin, Madison, WI 53706, USA
| | - Shawn D Mansfield
- US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA Department of Wood Science, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Paul Nicholson
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - John C Sedbrook
- School of Biological Sciences, Illinois State University, Normal, IL 61790 USA US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA
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Mottiar Y. Iodine biofortification through plant biotechnology. Nutrition 2013; 29:1431. [DOI: 10.1016/j.nut.2013.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 04/10/2013] [Accepted: 04/11/2013] [Indexed: 10/26/2022]
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Wan S, Mottiar Y, Johnson AM, Goto K, Altosaar I. Expression of the nos operon proteins from Pseudomonas stutzeri in transgenic plants to assemble nitrous oxide reductase. Transgenic Res 2012; 21:593-603. [PMID: 21938458 DOI: 10.1007/s11248-011-9555-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 09/02/2011] [Indexed: 11/27/2022]
Abstract
Nitrous oxide (N(2)O) is a stable greenhouse gas that plays a significant role in the destruction of the ozone layer. Soils are a significant source of atmospheric N(2)O. It is important to explore some innovative and effective biology-based strategies for N(2)O mitigation. The enzyme nitrous oxide reductase (N(2)OR), naturally found in soil bacteria, is responsible for catalysing the final step of the denitrification pathway, conversion of N(2)O to dintrogen gas (N(2)). To transfer this catalytic pathway from soil into plants and amplify the abundance of this essential mechanism (to reduce global warming), a mega-cassette of five coding sequences was assembled to produce transgenic plants heterologously expressing the bacterial nos operon in plant leaves. Both the single-gene transformants (nosZ) and the multi-gene transformants (nosFLZDY) produced active recombinant N(2)OR. Enzymatic activity was detected using the methyl viologen-linked enzyme assay, showing that extracts from both types of transgenic plants exhibited N(2)O-reducing activity. Remarkably, the single-gene strategy produced higher reductase capability than the whole-operon approach. The data indicate that bacterial N(2)OR expressed in plants could convert N(2)O into inert N(2) without involvement of other Nos proteins. Silencing by homologous signal sequences, or cryptic intracellular targeting are possible explanations for the low activities obtained. Expressing N(2)OR from Pseudomonas stutzeri in single-gene transgenic plants indicated that such ag-biotech solutions to climate change have the potential to be easily incorporated into existing genetically modified organism seed germplasm.
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Affiliation(s)
- Shen Wan
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, Centre for Research on Environmental Microbiology, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
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