Our research interests center on understanding the biosynthesis of plant phenylpropanoids, the molecular mechanisms
underlying their metabolic regulation, as well as the biogenesis of cell wall lignocelluloses.
Phenylpropanoids represent a large family of secondary metabolites. Their biosyntheses in terrestrial plants lead to
the formation of a variety of phenolics and polyphenolics with diverse biological activities. For example, as a cell
wall component, lignin imparts structural integrity to plant vasculature for water conductance and plant strength; as
signaling molecules or phytoalexins, flavonoids and isoflavonoids modulate plant-environmental interactions or defense
against phytopathogen infection; as cross-linker, phenolic esters bound to the cell wall non-cellulosic polymers or to
the lipophilic polyesters contribute to cell wall structural stability, or constitute physical barriers to control
water- and solute-permeability. These phenolics and polyphenolics in vascular plant represent a major sink of the
reduced carbon that, in some species, accounts for up to 30% photosynthetic carbon. The majority of phenylpropanoid
units, as building blocks, are deposited in the cell wall, forming a complex aromatic polymer, lignin. The cell-wall
polysaccharides and lignin constitute the most abundant renewable biomass (lignocelluloses) on earth. However, the
presence of intractable lignin in the cell wall is a formidable obstacle in producing renewable biofuels.
Through the integrated approaches of biochemistry, structural biology, protein engineering, and molecular genetics, our
group is undertaking four lines of research: 1) Exploring the molecular mechanisms of post-translational regulation,
and the macromolecular organization of phenylpropanoid-lignin biosynthesis. 2) Deciphering molecular mechanisms of
deposition or sequestration of lignin precursors and the “wall-bound” phenolics. And identifying transporter proteins
involved in cell wall lignification. 3) Employing X-ray crystallographic strategies to study the structure-function
of the key enzymes in the pathways and utilizing the structural information of the related enzymes to design and create
novel catalysts to modulate phenylpropanoid-lignin biosynthesis. 4) Characterizing the key enzymes and regulatory
elements involved in the synthesis and modification of hydroxycinnamate esters, particularly the wall-bound phenolics.
The goal of our studies is to obtain a deep understanding of the biosyntheses of phenylpropanoids, their precursor
translocation and sequestration, and their metabolic regulation. We then will apply our knowledge to reduce the
recalcitrance of lignocellulosic biomass toward the efficient, sustainable biofuel production, and to engineer the
value-added chemicals for plant- and human- health, and for various industrial applications.
- Zhang K., Novak O., Wei Z., Gou M., Zhang X., Yu Y., Yang H., Cai Y., Strnad M., and Liu C.-J.
Arabidopsis ABCG14 protein controls the acropetal translocation of root-synthesized cytokinins.
Nature Communications, 5:3274 (2014).
- Feng H., Qian Y., Gallagher F.J., Wu M., Zhang W., Yu L., Zhu Q., Zhang K., Liu C.-J., and Tappero R.
Lead accumulation and association with Fe on Typha latifolia root from an urban brownfield site.
Environmental Science and Pollution Research International, 20(6):3743-3750 (2013).
- Xu B., Gou J.-Y., Li F.G., Shangguan X.X., Zhao B., Yang C.Q., Wang L.J., Yuan S., Liu C.-J., and Chen X.Y.
A cotton BURP domain protein interacts with α-expansin and their co-expression promotes plant growth
and fruit production. Molecular Plant, 6(3):945-958 (2013).
- Zhang K., Halitschke R., Yin C., Liu C.-J., and Gan S.S. Salicylic acid 3-hydroxylase regulates
Arabidopsis leaf longevity by mediating salicylic acid catabolism. Proc. Natl. Acad. Sci. USA,
- Zhang X., Gou M., and Liu C.-J. Arabidopsis kelch repeat F-box proteins regulate phenylpropanoid
biosynthesis via controlling the turnover of phenylalanine ammonia-lyase. The Plant Cell, 25(12):4994-5010
- Cheng A.X., Gou J.Y., Yu X.H., Yang H., Fang X., Chen X.Y.,and Liu C.J.
Characterization and ectopic expression of a Populus hydroxyacid hydroxycinnamoyltransferase.
Mol. Plant, 6(6):1889-1903 (2013).
- Rimando A.M., Pan Z., Polashock J.J., Dayan F.E., Mizuno C.S., Snook M.E.,
Liu C.-J., and Baerson S.R. In planta production of the highly potent resveratrol
analogue pterostilbene via stilbene synthase and O-methyltransferase co-expression.
Plant Biotech. J., 10(3):269-283 (2012).
- Zhang K., Bhuiya M.W., Pazo J.R., Miao Y., Kim H., Ralph J., and Liu C.-J.
An engineered monolignol 4-O-methyltransferase depresses lignin biosynthesis
and confers novel metabolic capability in Arabidopsis.
Plant Cell, 24(7):3135-3152 (2012).
Gou J.Y., Miller L.A., Hou G., Yu X.-H., Chen X.-Y. and Liu C.-J.
Acetylesterase-mediated deacetylation of pectin impairs cell elongation,
pollen germination, and plant reproduction.
Plant Cell, 24(1):50-65 (2012).
Deciphering the enigma of lignification: Precursor transport, oxidation, and the
topochemistry of lignin assembly.
Mol. Plant, 5(2):304–317 (2012).
Manjasetty B.A., Yu X.-H., Panjikar S., Taguchi G., Chance M.R. and Liu C.-J.
Structural basis for modification of flavonol- and naphthol-glucoconjugates by
Nicotiana tabacum malonyltransferase (NtMaT1).
Planta, 236(3):781–793 (2012).
Zhang K.W., Bhuiya M.W., Pazo J.R., Miao Y., Kim H., Ralph J. and Liu C.-J.
An engineered monolignol 4-O-methyltransferase Depresses lignin polymerization and confers novel metabolic capability in Arabidopsis.
Plant Cell 24(7):3135-3152 (2012).
Gou J.Y., Felippes F.F., Liu C.-J., Weigel D. and Wang J.W.
Negative Regulation of Anthocyanin Biosynthesis in Arabidopsis by a miR156-Targeted SPL Transcription Factor.
Plant Cell, 23(4):1512-1522 (2011).
Liu C.-J., Miao Y.C. and Zhang K.W.
Sequestration and transport of lignin monomeric precursors.
Molecules, 16(1):710-727 (2011).
Bhuiya M.W. and Liu C.-J.
Engineering monolignol 4-O-methyltransferases to modulate lignin biosynthesis.
J. Biol. Chem., 285(1):277-285 (2010).
Biosynthesis of hydroxycinnamate conjugates: Implications for sustainable biomass and biofuel production.
Biofuels, 1(5):745-761 (2010).
Miao Y.-C. and Liu C.-J.
ATP-binding cassette-like transporters are involved in the transport of lignin precursors across plasma and vacuolar membranes.
Proc. Natl. Acad. Sci. USA,107(52):22728-22733 (2010).
Bhuiya M.W. and Liu C.-J.
A cost-effective colorimetric assay for phenolic O methyltransferases and characterization of caffeate 3-O-methyltransferases from Populus trichocarpa.
Analytical Biochemistry, 384(1): 151-158 (2009).
Gou J.-Y., Yu X.-H. and Liu C.-J.
A hydroxycinnamoyltransferase responsible for synthesizing suberin aromatics in Arabidopsis.
Proc. Natl. Acad. Sci. USA, 106:18855-18860 (2009).
Yu, X.-H., Gou, J.-Y. and Liu C.-J.
BAHD superfamily of acyl-CoA dependent acyltransferases in Populus and Arabidopsis: Bioinformatics and gene expression.
Plant Mol Biol., 70(4):421-442 (2009).
Baerson S.R., Dayan F.E., Rimando A.M., Dhammika Nanayakkara N.P., Liu C.J., Schroder J., Fishbein M., Pan Z., Kagan I.A., Pratt, L.H.,
Cordonnier-Pratt M.-M. and Duke S.O.
A functional genomics investigation of allelochemical biosynthesis in Sorghum biocolor root hairs.
J. Biol. Chem., 283(6):3231-47 (2008).
Gou J., Park S., Yu X.-H., Miller L.M. and Liu C.-J.
Compositional characterization and imaging of “wall-bound” acylesters of Populus trichocarpa reveal differential accumulation of acyl molecules in normal and reactive woods.
Planta, 229(1):15-24 (2008).
Yu X-H., Chen M.-H. and Liu C.-J.
Nucleocytoplasmic-localized acyltransferases catalyze the malonylation of 7-O-glycosidic (iso)flavones in Medicago truncatula.
Plant Journal, 55(3):382-396 (2008).
Naoumkina M., Farag M.A., Sumner L.W., Tang Y., Liu C.-J. and Dixon, R.A.
Different mechanisms for phytoalexin induction by pathogen and wound signals in Medicago truncatula.
Proc. Natl. Acad. Sci. USA, 104(46):17909-17915 (2007).
Deavours B.E., Liu C.-J., Naoumkina M., Tang Y., Farag M.A., Sumner L.W., Noel J.P. and Dixon R.A.
Functional analysis of members of the isoflavone and isoflavanone O-methyltransferase enzyme
families from the model legume Medicago truncatula.
Plant Mol Biol., 62(4-5):715-733 (2006).
Coiner H., Schröder G., Wehinger E., Liu C.-J., Noel J.P., Schwab W. and Schröder J.
Methylation of sulfhydryl groups: a new function in a family of small molecule plant
Plant J, 46(2):193-205 (2006).
Liu C.-J., Deavours B.E., Richard S.B., Ferrer J.L., Blount J.W., Huhman D., Dixon R.A. and Noel J.P.
Structural basis for dual functionality of isoflavonoid O-methyltransferases in the evolution
of plant defense responses.
Plant Cell, 18(12):3656-3669 (2006).
Liu C.-J. and Noel J.P.
Flavonoids: recent advances in molecular biology, biochemistry, pharmaceutical
applications and metabolic engineering.
In: Plant Genetic Engineering Vol. 7: Metabolic Engineering and Molecular Farming, (Ed. Jaiwal P.K.)
Studium Press, Houston, pp 225-259 (2006).
Yu X.-H. and Liu C.-J.
Development of an analytical method for genome-wide functional identification of plant acyl-coenzyme A-dependent acyltransferases.
Anal Biochem, 358(1):146-148 (2006).
Liu C.-J., Huhman D., Sumner L.W. and Dixon R.A.
Regiospecific hydroxylation of isoflavones by CYP81E enzymes in Medicago truncatula.
Plant J., 36:471-484 (2003).
Liu C.-J., Blount J.W., Steele C.L. and Dixon R.A.
Bottlenecks for the metabolic engineering of isoflavone glycoconjugates in Arabidopsis.
Proc Natl Acad Sci USA, 99:14578-14583 (2002).
Liu C.-J., Heinstein P. and Chen X.Y.
Expression pattern of genes encoding farnesyl diphosphate synthase and sesquiterpene cyclase
in cotton suspension-cultured cells treated with fungal elicitors.
Mol Plant Microbe Interact, 12(12):1095-1104 (1999).