Abstract
Proanthocyanidins (PAs) are the second most abundant plant polyphenolic compounds after lignin. PAs affect taste, mouth feel and astringency of many fruits, wines and beverages1,2, have been associated with reduced risks of cardiovascular disease, cancer and Alzheimer's disease3–5, can improve nutrition and prevent bloat in ruminant animals6 and enhance soil nitrogen retention7. PAs are oligomers and polymers of flavan-3-ols, primarily (–)-epicatechin and (+)-catechin, but the mechanism by which the monomers polymerize and become insoluble is currently unknown. Leucoanthocyanidin reductase (LAR) has been shown to convert leucocyanidin to (+)-catechin8,9. Here, we report that loss of function of LAR in the model legume Medicago truncatula leads unexpectedly to loss of soluble epicatechin-derived PAs, increased levels of insoluble PAs, and accumulation of 4β-(S-cysteinyl)-epicatechin, which provides the 4→8 linked extension units during non-enzymatic PA polymerization. LAR converts 4β-(S-cysteinyl)-epicatechin back to epicatechin, the starter unit in PAs, thereby regulating the relative proportions of starter and extension units and consequently the degree of PA oligomerization.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 digital issues and online access to articles
$119.00 per year
only $9.92 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Gonzalo-Diago, A., Dizy, M. & Fernández-Zurbano, P. Taste and mouthfeel properties of red wines proanthocyanidins and their relation to the chemical composition. J. Agric. Food Chem. 61, 8861–8870 (2013).
Lesschaeve, I. & Noble, A. C. Polyphenols: factors influencing their sensory properties and their effects on food and beverage preferences. Am. J. Clin. Nutr. 81, 330s–335s (2005).
Bagchi, D. et al. Free radicals and grape seed proanthocyanidin extract: importance in human health and disease prevention. Toxicology 148, 187–197 (2000).
Cos, P. et al. Proanthocyanidins in health care: current and new trends. Curr. Med. Chem. 11, 1345–1359 (2004).
Middleton, E. Jr, Kandaswami, C. & Theoharides, T. C. The effects of plant flavonoids on mammalian cells: implications for inflammation, heart disease, and cancer. Pharmacol. Rev. 52, 673–751 (2000).
Lees, G. L. Condensed tannins in some forage legumes: their role in the prevention of ruminant pasture bloat. Basic Life Sci. 59, 915–934 (1992).
Joanisse, G. D., Bradley, R. L., Preston, C. M. & Bending, G. D. Sequestration of soil nitrogen as tannin-protein complexes may improve the competitive ability of sheep laurel (Kalmia angustifolia) relative to black spruce (Picea mariana). New Phytol. 181, 187–198 (2009).
Pang, Y., Peel, G. J., Wright, E., Wang, Z. & Dixon, R. A. Early steps in proanthocyanidin biosynthesis in the model legume Medicago truncatula. Plant Physiol. 145, 601–615 (2007).
Tanner, G. J. et al. Proanthocyanidin biosynthesis in plants. Purification of legume leucoanthocyanidin reductase and molecular cloning of its cDNA. J. Biol. Chem. 278, 31647–31656 (2003).
Devic, M. et al. The BANYULS gene encodes a DFR-like protein and is a marker of early seed coat development. Plant J. 19, 387–398 (1999).
Xie, D. Y., Sharma, S. B., Paiva, N. L., Ferreira, D. & Dixon, R. A. Role of anthocyanidin reductase, encoded by BANYULS in plant flavonoid biosynthesis. Science 299, 396–399 (2003).
Bogs, J. et al. Proanthocyanidin synthesis and expression of genes encoding leucoanthocyanidin reductase and anthocyanidin reductase in developing grape berries and grapevine leaves. Plant Physiol. 139, 652–663 (2005).
Liu, Y., Shi, Z., Maximova, S., Payne, M. J. & Guiltinan, M. J. Proanthocyanidin synthesis in Theobroma cacao: genes encoding anthocyanidin synthase, anthocyanidin reductase, and leucoanthocyanidin reductase. BMC Plant Biol. 13, 202 (2013).
Tadege, M. et al. Large-scale insertional mutagenesis using the Tnt1 retrotransposon in the model legume Medicago truncatula. Plant J. 54, 335–347 (2008).
Kiatgrajai, P., Wellons, J. D., Gollob, L. & White, J. D. Kinetics of epimerization of (+)-catechin and its rearrangement to catechinic acid. J. Org. Chem. 47, 2910–2912 (1982).
Pang, Y., Peel, G. J., Sharma, S. B., Tang, Y. & Dixon, R. A. A transcript profiling approach reveals an epicatechin-specific glucosyltransferase expressed in the seed coat of Medicago truncatula. Proc. Natl Acad. Sci. USA 105, 14210–14215 (2008).
Mauge, C. et al. Crystal structure and catalytic mechanism of leucoanthocyanidin reductase from Vitis vinifera. J. Mol. Biol. 397, 1079–1091 (2010).
Liu, C., Jun, J. H. & Dixon, R. A. MYB5 and MYB14 play pivotal roles in seed coat polymer biosynthesis in Medicago truncatula. Plant Physiol. 165, 1424–1439 (2014).
Callemien, D. & Collin, S. Use of RP-HPLC-ESI(–)MS/MS to differentiate various proanthocyanidin isomers in lager beer extracts. J. Am. S. Brewing Chem. 66, 109–115 (2008).
Torres, J. L. et al. Cysteinyl-flavan-3-ol conjugates from grape procyanidins. Antioxidant and antiproliferative properties. Bioorg. Med. Chem. 10, 2497–2509 (2002).
Torres, J. L., Lozano, C. & Maher, P. Conjugation of catechins with cysteine generates antioxidant compounds with enhanced neuroprotective activity. Phytochemistry 66, 2032–2037 (2005).
Jiang, X. et al. Analysis of accumulation patterns and preliminary study on the condensation mechanism of proanthocyanidins in the tea plant [Camellia sinensis]. Sci. Rep. 5, 8742 (2015).
Dixon, R. A., Xie, D. Y. & Sharma, S. B. Proanthocyanidins—a final frontier in flavonoid research? New Phytol. 165, 9–28 (2005).
Hemingway, R. W. & Foo, L. Y. Condensed tannins: quinone methide intermediates in procyanidin synthesis. J. Chem. Soc. Chem. Commun. 1035–1036 (1983).
Yan, Y., Li, Z. & Koffas, M. A. High-yield anthocyanin biosynthesis in engineered Escherichia coli. Biotechnol. Bioeng. 100, 126–140 (2008).
Lim, C. G. et al. Development of a recombinant Escherichia coli strain for overproduction of the plant pigment anthocyanin. Appl. Environ. Microbiol. 81, 6276–6284 (2015).
Wellmann, F. et al. Anthocyanidin synthase from Gerbera hybrida catalyzes the conversion of (+)-catechin to cyanidin and a novel procyanidin. FEBS Lett. 580, 1642–1648 (2006).
Ferraro, K. et al. Characterization of proanthocyanidin metabolism in pea (Pisum sativum) seeds. BMC Plant Biol. 14, 1–17 (2014).
Huang, Y.-F. et al. Dissecting genetic architecture of grape proanthocyanidin composition through quantitative trait locus mapping. BMC Plant Biol. 12, 1–19 (2012).
Akagi, T., Katayama-Ikegami, A. & Yonemori, K. Proanthocyanidin biosynthesis of persimmon (Diospyros kaki Thunb.) fruit. Sci. Hort. 130, 373–380 (2011).
Liao, L. et al. Molecular characterization of genes encoding leucoanthocyanidin reductase involved in proanthocyanidin biosynthesis in apple. Frontiers Plant Sci. 6, 243 (2015).
Acknowledgements
This work was supported by the University of North Texas and Forage Genetics International. We thank J. Wen and X. Chen for screening for M. truncatula Tnt1 insertion mutants.
Author information
Authors and Affiliations
Contributions
C.L. and R.A.D. conceived and designed the project, C.L. carried out the experiments, V.S. provided assistance for UPLC/MS analysis, X.W. carried out molecular modelling and docking analyses and C.L. and R.A.D. wrote the paper.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Information
Supplementary Figures 1–23, Supplementary Methods, Supplementary References. (PDF 1336 kb)
Rights and permissions
About this article
Cite this article
Liu, C., Wang, X., Shulaev, V. et al. A role for leucoanthocyanidin reductase in the extension of proanthocyanidins. Nature Plants 2, 16182 (2016). https://doi.org/10.1038/nplants.2016.182
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/nplants.2016.182
This article is cited by
-
An unconventional proanthocyanidin pathway in maize
Nature Communications (2023)
-
Synthesis, characterization and application of oligomeric proanthocyanidin-rich dual network hydrogels
Scientific Reports (2023)
-
Transcriptional regulation of proanthocyanidin biosynthesis pathway genes and transcription factors in Indigofera stachyodes Lindl. roots
BMC Plant Biology (2022)
-
A role for ascorbate conjugates of (+)-catechin in proanthocyanidin polymerization
Nature Communications (2022)
-
Exploring Nrf2 as a therapeutic target in testicular dysfunction
Cell and Tissue Research (2022)