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Vincent L. Chiang

Bio: Vincent L. Chiang is an academic researcher from Northeast Forestry University. The author has contributed to research in topics: Monolignol & Lignin. The author has an hindex of 54, co-authored 183 publications receiving 11764 citations. Previous affiliations of Vincent L. Chiang include North Carolina State University & University of British Columbia.


Papers
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Journal ArticleDOI
TL;DR: In this article, the expression of a lignin biosynthetic pathway gene Pt4CL1 encoding 4-coumarate:coenzyme A ligase (4CL) has been downregulated by antisense inhibition.
Abstract: Because lignin limits the use of wood for fiber, chemical, and energy production, strategies for its downregulation are of considerable interest. We have produced transgenic aspen (Populus tremuloides Michx.) trees in which expression of a lignin biosynthetic pathway gene Pt4CL1 encoding 4-coumarate:coenzyme A ligase (4CL) has been downregulated by antisense inhibition. Trees with suppressed Pt4CL1 expression exhibited up to a 45% reduction of lignin, but this was compensated for by a 15% increase in cellulose. As a result, the total lignin-cellulose mass remained essentially unchanged. Leaf, root, and stem growth were substantially enhanced, and structural integrity was maintained both at the cellular and whole-plant levels in the transgenic lines. Our results indicate that lignin and cellulose deposition could be regulated in a compensatory fashion, which may contribute to metabolic flexibility and a growth advantage to sustain the long-term structural integrity of woody perennials.

718 citations

05 Mar 2001
TL;DR: It is indicated that lignin and cellulose deposition could be regulated in a compensatory fashion, which may contribute to metabolic flexibility and a growth advantage to sustain the long-term structural integrity of woody perennials.
Abstract: Because lignin limits the use of wood for fiber, chemical, and energy production, strategies for its downregulation are of considerable interest. We have produced transgenic aspen (Populus tremuloides Michx.) trees in which expression of a lignin biosynthetic pathway gene Pt4CL1 encoding 4-coumarate:coenzyme A ligase (4CL) has been downregulated by antisense inhibition. Trees with suppressed Pt4CL1 expression exhibited up to a 45% reduction of lignin, but this was compensated for by a 15% increase in cellulose. As a result, the total lignin–cellulose mass remained essentially unchanged. Leaf, root, and stem growth were substantially enhanced, and structural integrity was maintained both at the cellular and whole-plant levels in the transgenic lines. Our results indicate that lignin and cellulose deposition could be regulated in a compensatory fashion, which may contribute to metabolic flexibility and a growth advantage to sustain the long-term structural integrity of woody perennials.

717 citations

Journal ArticleDOI
TL;DR: A simple and sensitive real-time PCR method for quantifying the expression of plant miRNAs and revealed miRNA tissue-specific expression patterns that cannot be resolved by Northern blot analysis and may therefore be widely useful for characterizing miRNA expression in plants as well as in animals.
Abstract: MicroRNAs (miRNAs) are 20-24 nucleotide RNAs that are predicted to play regulatory roles in animals and plants. Here we report a simple and sensitive real-time PCR method for quantifying the expression of plant miRNAs. Total RNA, including miRNAs, was polyadenylated and reverse-transcribed with a poly(T) adapter into cDNAs for real-time PCR using the miRNA-specific forward primer and the sequence complementary to the poly(T) adapter as the reverse primer. Several Arabidopsis miRNA sequences were tested using SYBR Green reagent, demonstrating that this method, using as little as 100 pg total RNA, could readily discriminate the expression of miRNAs having asfew as one nucleotide sequence difference. This method also revealed miRNA tissue-specific expression patterns that cannot be resolved by Northern blot analysis and may therefore be widely useful for characterizing miRNA expression in plants as well as in animals.

700 citations

Journal ArticleDOI
TL;DR: It is shown that plant miRNAs can be induced by mechanical stress and may function in one of the most critical defense systems for structural and mechanical fitness.
Abstract: MicroRNAs (miRNAs) are small, noncoding RNAs that can play crucial regulatory roles in eukaryotes by targeting mRNAs for silencing. To test whether miRNAs play roles in the regulation of wood development in tree species, we isolated small RNAs from the developing xylem of Populus trichocarpa stems and cloned 22 miRNAs. They are the founding members of 21 miRNA gene families for 48 miRNA sequences, represented by 98 loci in the Populus genome. A majority of these miRNAs were predicted to target developmental- and stress/defense-related genes and possible functions associated with the biosynthesis of cell wall metabolites. Of the 21 P. trichocarpa miRNA families, 11 have sequence conservation in Arabidopsis thaliana but exhibited species-specific developmental expression patterns, suggesting that even conserved miRNAs may have different regulatory roles in different species. Most unexpectedly, the remaining 10 miRNAs, for which 17 predicted targets were experimentally validated in vivo, are absent from the Arabidopsis genome, suggesting possible roles in tree-specific processes. In fact, the expression of a majority of the cloned miRNAs was upregulated or downregulated in woody stems in a manner consistent with tree-specific corrective growth against tension and compression stresses, two constant mechanical loads in trees. Our results show that plant miRNAs can be induced by mechanical stress and may function in one of the most critical defense systems for structural and mechanical fitness.

604 citations

Journal ArticleDOI
TL;DR: The cloning of small RNAs from abiotic stressed tissues of Populus trichocarpa (Ptc) and the identification of 68 putative miRNA sequences that can be classified into 27 families based on sequence homology are reported, which suggests that the members of a family may have different functions.
Abstract: MicroRNAs (miRNAs), a group of small non-coding RNAs, have recently become the subject of intense study. They are a class of post-transcriptional negative regulators playing vital roles in plant development and growth. However, little is known about their regulatory roles in the responses of trees to the stressful environments incurred over their long-term growth. Here, we report the cloning of small RNAs from abiotic stressed tissues of Populus trichocarpa (Ptc) and the identification of 68 putative miRNA sequences that can be classified into 27 families based on sequence homology. Among them, nine families are novel, increasing the number of the known Ptc-miRNA families from 33 to 42. A total of 346 targets was predicted for the cloned Ptc-miRNAs using penalty scores of

479 citations


Cited by
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Journal ArticleDOI
27 Jan 2006-Science
TL;DR: The integration of agroenergy crops and biorefinery manufacturing technologies offers the potential for the development of sustainable biopower and biomaterials that will lead to a new manufacturing paradigm.
Abstract: Biomass represents an abundant carbon-neutral renewable resource for the production of bioenergy and biomaterials, and its enhanced use would address several societal needs. Advances in genetics, biotechnology, process chemistry, and engineering are leading to a new manufacturing concept for converting renewable biomass to valuable fuels and products, generally referred to as the biorefinery. The integration of agroenergy crops and biorefinery manufacturing technologies offers the potential for the development of sustainable biopower and biomaterials that will lead to a new manufacturing paradigm.

5,344 citations

Journal ArticleDOI
TL;DR: This work has shown that the regulation of miRNA metabolism and function by a range of mechanisms involving numerous protein–protein and protein–RNA interactions has an important role in the context-specific functions of miRNAs.
Abstract: MicroRNAs (miRNAs) are a large family of post-transcriptional regulators of gene expression that are ~21 nucleotides in length and control many developmental and cellular processes in eukaryotic organisms. Research during the past decade has identified major factors participating in miRNA biogenesis and has established basic principles of miRNA function. More recently, it has become apparent that miRNA regulators themselves are subject to sophisticated control. Many reports over the past few years have reported the regulation of miRNA metabolism and function by a range of mechanisms involving numerous protein-protein and protein-RNA interactions. Such regulation has an important role in the context-specific functions of miRNAs.

4,123 citations

Journal ArticleDOI
TL;DR: Limiting discussion to stress-induced phenylpropanoids eliminates few of the structural classes, because many compounds that are constitutive in one plant species or tissue can be induced by various stresses in another species or in another tissue of the same plant.
Abstract: Phenylpropanoid compounds encompass a wide range of structural classes and biological functions. Limiting discussion to stress-induced phenylpropanoids eliminates few of the structural classes, because many compounds thst are constitutive in one plant species or tissue can be induced by various stresses in another species or in another tissue of the same plant (Beggs et al., 1987; Christie et al., 1994).

4,046 citations

Journal ArticleDOI
Gerald A. Tuskan1, Gerald A. Tuskan2, Stephen P. DiFazio1, Stephen P. DiFazio3, Stefan Jansson4, Joerg Bohlmann5, Igor V. Grigoriev6, Uffe Hellsten6, Nicholas H. Putnam6, Steven G. Ralph5, Stephane Rombauts7, Asaf Salamov6, Jacquie Schein, Lieven Sterck7, Andrea Aerts6, Rishikeshi Bhalerao4, Rishikesh P. Bhalerao8, Damien Blaudez9, Wout Boerjan7, Annick Brun9, Amy M. Brunner10, Victor Busov11, Malcolm M. Campbell12, John E. Carlson13, Michel Chalot9, Jarrod Chapman6, G.-L. Chen1, Dawn Cooper5, Pedro M. Coutinho14, Jérémy Couturier9, Sarah F. Covert15, Quentin C. B. Cronk5, R. Cunningham1, John M. Davis16, Sven Degroeve7, Annabelle Déjardin9, Claude W. dePamphilis13, John C. Detter6, Bill Dirks17, Inna Dubchak18, Inna Dubchak6, Sébastien Duplessis9, Jürgen Ehlting5, Brian E. Ellis5, Karla C Gendler19, David Goodstein6, Michael Gribskov20, Jane Grimwood21, Andrew Groover22, Lee E. Gunter1, Björn Hamberger5, Berthold Heinze, Yrjö Helariutta23, Yrjö Helariutta24, Yrjö Helariutta8, Bernard Henrissat14, D. Holligan15, Robert A. Holt, Wenyu Huang6, N. Islam-Faridi22, Steven J.M. Jones, M. Jones-Rhoades25, Richard A. Jorgensen19, Chandrashekhar P. Joshi11, Jaakko Kangasjärvi23, Jan Karlsson4, Colin T. Kelleher5, Robert Kirkpatrick, Matias Kirst16, Annegret Kohler9, Udaya C. Kalluri1, Frank W. Larimer1, Jim Leebens-Mack15, Jean-Charles Leplé9, Philip F. LoCascio1, Y. Lou6, Susan Lucas6, Francis Martin9, Barbara Montanini9, Carolyn A. Napoli19, David R. Nelson26, C D Nelson22, Kaisa Nieminen23, Ove Nilsson8, V. Pereda9, Gary F. Peter16, Ryan N. Philippe5, Gilles Pilate9, Alexander Poliakov18, J. Razumovskaya1, Paul G. Richardson6, Cécile Rinaldi9, Kermit Ritland5, Pierre Rouzé7, D. Ryaboy18, Jeremy Schmutz21, J. Schrader27, Bo Segerman4, H. Shin, Asim Siddiqui, Fredrik Sterky, Astrid Terry6, Chung-Jui Tsai11, Edward C. Uberbacher1, Per Unneberg, Jorma Vahala23, Kerr Wall13, Susan R. Wessler15, Guojun Yang15, T. Yin1, Carl J. Douglas5, Marco A. Marra, Göran Sandberg8, Y. Van de Peer7, Daniel S. Rokhsar17, Daniel S. Rokhsar6 
15 Sep 2006-Science
TL;DR: The draft genome of the black cottonwood tree, Populus trichocarpa, has been reported in this paper, with more than 45,000 putative protein-coding genes identified.
Abstract: We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in Populus than in Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average from 1.4 to 1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.

4,025 citations

Journal ArticleDOI
16 May 2014-Science
TL;DR: Recent developments in genetic engineering, enhanced extraction methods, and a deeper understanding of the structure of lignin are yielding promising opportunities for efficient conversion of this renewable resource to carbon fibers, polymers, commodity chemicals, and fuels.
Abstract: Background Lignin, nature’s dominant aromatic polymer, is found in most terrestrial plants in the approximate range of 15 to 40% dry weight and provides structural integrity. Traditionally, most large-scale industrial processes that use plant polysaccharides have burned lignin to generate the power needed to productively transform biomass. The advent of biorefineries that convert cellulosic biomass into liquid transportation fuels will generate substantially more lignin than necessary to power the operation, and therefore efforts are underway to transform it to value-added products. Production of biofuels from cellulosic biomass requires separation of large quantities of the aromatic polymer lignin. In planta genetic engineering, enhanced extraction methods, and a deeper understanding of the structure of lignin are yielding promising opportunities for efficient conversion of this renewable resource to carbon fibers, polymers, commodity chemicals, and fuels. [Credit: Oak Ridge National Laboratory, U.S. Department of Energy] Advances Bioengineering to modify lignin structure and/or incorporate atypical components has shown promise toward facilitating recovery and chemical transformation of lignin under biorefinery conditions. The flexibility in lignin monomer composition has proven useful for enhancing extraction efficiency. Both the mining of genetic variants in native populations of bioenergy crops and direct genetic manipulation of biosynthesis pathways have produced lignin feedstocks with unique properties for coproduct development. Advances in analytical chemistry and computational modeling detail the structure of the modified lignin and direct bioengineering strategies for targeted properties. Refinement of biomass pretreatment technologies has further facilitated lignin recovery and enables catalytic modifications for desired chemical and physical properties. Outlook Potential high-value products from isolated lignin include low-cost carbon fiber, engineering plastics and thermoplastic elastomers, polymeric foams and membranes, and a variety of fuels and chemicals all currently sourced from petroleum. These lignin coproducts must be low cost and perform as well as petroleum-derived counterparts. Each product stream has its own distinct challenges. Development of renewable lignin-based polymers requires improved processing technologies coupled to tailored bioenergy crops incorporating lignin with the desired chemical and physical properties. For fuels and chemicals, multiple strategies have emerged for lignin depolymerization and upgrading, including thermochemical treatments and homogeneous and heterogeneous catalysis. The multifunctional nature of lignin has historically yielded multiple product streams, which require extensive separation and purification procedures, but engineering plant feedstocks for greater structural homogeneity and tailored functionality reduces this challenge.

2,958 citations