Transgenic Poplar Designed for Biofuels

Bryant, Nathan; Pu, Yunqiao; Tschaplinski, Timothy J.; Tuskan, Gerald A.; Muchero, Wellington; Kalluri, Udaya C.; Yoo, Chang Geun; Ragauskas, Arthur J.

doi:10.1016/j.tplants.2020.03.008

Cited by 52 publications

(30 citation statements)

References 82 publications

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“…During the past three decades, several types of genetically modified plants, including xylanase- or xyloglucanase-overexpressing poplars (reviewed by Donev et al, 2018 ), and poplars with various kinds of lignin and cellulose or general cell wall modifications (reviewed by Chanoca et al, 2019 ; Bryant et al, 2020 ) have shown substantial improvements in wood-processing properties. However, there have been relatively few field trial studies of these lines.…”

Section: Perspectivesmentioning

confidence: 99%

Saccharification Potential of Transgenic Greenhouse- and Field-Grown Aspen Engineered for Reduced Xylan Acetylation

et al. 2021

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High acetylation of xylan in hardwoods decreases their value as biorefinery feedstocks. To counter this problem, we have constitutively suppressed RWA genes encoding acetyl-CoA transporters using the 35S promoter, or constitutively and wood-specifically (using the WP promoter) expressed fungal acetyl xylan esterases of families CE1 (AnAXE1) and CE5 (HjAXE), to reduce acetylation in hybrid aspen. All these transformations improved the saccharification of wood from greenhouse-grown trees. Here, we describe the chemical properties and saccharification potential of the resulting lines grown in a five-year field trial, and one type of them (WP:AnAXE1) in greenhouse conditions. Chemically, the lignocellulose of the field- and greenhouse-field-grown plants slightly differed, but the reductions in acetylation and saccharification improvement of engineered trees were largely maintained in the field. The main novel phenotypic observation in the field was higher lignification in lines with the WP promoter than those with the 35S promoter. Following growth in the field, saccharification glucose yields were higher from most transformed lines than from wild-type (WT) plants with no pretreatment, but there was no improvement in saccharification with acid pretreatment. Thus, acid pretreatment removes most recalcitrance caused by acetylation. We found a complex relationship between acetylation and glucose yields in saccharification without pretreatment, suggesting that other variables, for example, the acetylation pattern, affect recalcitrance. Bigger gains in glucose yields were observed in lines with the 35S promoter than in those with the WP promoter, possibly due to their lower lignin content. However, better lignocellulose saccharification of these lines was offset by a growth penalty and their glucose yield per tree was lower. In a comparison of the best lines with each construct, WP:AnAXE1 provided the highest glucose yield per tree from saccharification, with and without pretreatment, WP:HjAXE yields were similar to those of WT plants, and yields of lines with other constructs were lower. These results show that lignocellulose properties of field-grown trees can be improved by reducing cell wall acetylation using various approaches, but some affect productivity in the field. Thus, better understanding of molecular and physiological consequences of deacetylation is needed to obtain quantitatively better results.

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Section: Perspectivesmentioning

confidence: 99%

Saccharification Potential of Transgenic Greenhouse- and Field-Grown Aspen Engineered for Reduced Xylan Acetylation

et al. 2021

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“…Woody biomass makes up 57% of all carbon biomass on earth (Bar‐On et al ., 2018). The abundance of woody biomass availability, combined with fast‐growth, makes short‐rotation forest trees, such as Populus , Salix , Eucalyptus , and their hybrids, promising feedstock sources to meet the world's demands for sustainable bioenergy (Bryant et al ., 2020).…”

Section: Plant Biomass Feedstocks With Industrial Potentialmentioning

confidence: 99%

“…Therefore, much effort has been made to overcome the recalcitrant barrier of lignocellulosic biomass for bio‐based fuels and chemical production. Feedstock pretreatment can facilitate delignification or disruption of lignin‐cellulose linkages to improve the accessibility of enzymes and cell‐wall digestive microbes to cellulose and hemicelluloses (Bryant et al ., 2020; Straub et al ., 2020a). Common biomass pretreatments encompass physical methods (e.g., pyrolysis and mechanical particle‐size reduction), chemical methods (e.g., acid, alkaline, ionic liquids, and ozonolysis), and physical–chemical methods (e.g., steam, carbon dioxide, and ammonia fibre explosion) (Li et al ., 2014).…”

Section: Plant Biomass Feedstocks With Industrial Potentialmentioning

confidence: 99%

Thermophilic microbial deconstruction and conversion of natural and transgenic lignocellulose

Bing

Sulis

Wang

et al. 2021

Environ Microbiol Rep

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The potential to convert renewable plant biomasses into fuels and chemicals by microbial processes presents an attractive, less environmentally intense alternative to conventional routes based on fossil fuels. This would best be done with microbes that natively deconstruct lignocellulose and concomitantly form industrially relevant products, but these two physiological and metabolic features are rarely and simultaneously observed in nature. Genetic modification of both plant feedstocks and microbes can be used to increase lignocellulose deconstruction capability and generate industrially relevant products. Separate efforts on plants and microbes are ongoing, but these studies lack a focus on optimal, complementary combinations of these disparate biological systems to obtain a convergent technology. Improving genetic tools for plants have given rise to the generation of low-lignin lines that are more readily solubilized by microorganisms. Most focus on the microbiological front has involved thermophilic bacteria from the genera Caldicellulosiruptor and Clostridium, given their capacity to degrade lignocellulose and to form bio-products through metabolic engineering strategies enabled by ever-improving molecular genetics tools. Bioengineering plant properties to better fit the deconstruction capabilities of candidate consolidated bioprocessing microorganisms has potential to achieve the efficient lignocellulose deconstruction needed for industrial relevance.

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“…Poplar is an important energy and timber species with a fast growth rate, easy asexual reproduction, relatively small genome, and easy transformation [19,20]. With the successful sequencing of the P. trichocarpa genome, poplar has become an ideal model for the study of woody plants [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Genome-Wide Identification and Characterization of the FAR1/FHY3 Family in Populus trichocarpa Torr. & Gray and Expression Analysis in Light Response

Zhang

et al. 2021

Forests

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Light is an important environmental factor for plant growth, and in higher plants, phytochrome A (phyA) is the predominant far-red photoreceptor, involved in various photoresponses. The FAR1/FHY3 transcription factor family, derived from transposases, is able to regulate plant development in response to multiple photosensitizers phytochrome. In total, 51 PtrFRSs were identified in the poplar genome, and were divided into 4 subfamilies. Among them, 47 PtrFRSs are located on 17 chromosomes. Upstream cis-acting elements of the PtrFRS genes were classified into three categories: growth and metabolism, stress and hormone, and the hormone and stress categories contained most of the cis-acting elements. Analysis of the regulatory networks and expression patterns showed that most PtrFRSs responded to changes in light intensity and were involved in the regulation of phytochromes. In this study, 51 PtrFRSs were identified and comprehensively bioinformatically analyzed, and preliminary functional analysis and prediction of PtrFRSs was carried out.

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Transgenic Poplar Designed for Biofuels

Cited by 52 publications

References 82 publications

Saccharification Potential of Transgenic Greenhouse- and Field-Grown Aspen Engineered for Reduced Xylan Acetylation

Saccharification Potential of Transgenic Greenhouse- and Field-Grown Aspen Engineered for Reduced Xylan Acetylation

Thermophilic microbial deconstruction and conversion of natural and transgenic lignocellulose

Genome-Wide Identification and Characterization of the FAR1/FHY3 Family in Populus trichocarpa Torr. & Gray and Expression Analysis in Light Response

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