Format

Send to

Choose Destination
Curr Biol. 2012 Jul 10;22(13):1207-12. doi: 10.1016/j.cub.2012.04.064. Epub 2012 Jun 14.

AtABCG29 is a monolignol transporter involved in lignin biosynthesis.

Author information

1
Institute of Plant Biology, University of Zurich, 8008 Zurich, Switzerland. saalmar333@hotmail.com

Abstract

Lignin is the defining constituent of wood and the second most abundant natural polymer on earth. Lignin is produced by the oxidative coupling of three monolignols: p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol. Monolignols are synthesized via the phenylpropanoid pathway and eventually polymerized in the cell wall by peroxidases and laccases. However, the mechanism whereby monolignols are transported from the cytosol to the cell wall has remained elusive. Here we report the discovery that AtABCG29, an ATP-binding cassette transporter, acts as a p-coumaryl alcohol transporter. Expression of AtABCG29 promoter-driven reporter genes and a Citrine-AtABCG29 fusion construct revealed that AtABCG29 is targeted to the plasma membrane of the root endodermis and vascular tissue. Moreover, yeasts expressing AtABCG29 exhibited an increased tolerance to p-coumaryl alcohol by excreting this monolignol. Vesicles isolated from yeasts expressing AtABCG29 exhibited a p-coumaryl alcohol transport activity. Loss-of-function Arabidopsis mutants contained less lignin subunits and were more sensitive to p-coumaryl alcohol. Changes in secondary metabolite profiles in abcg29 underline the importance of regulating p-coumaryl alcohol levels in the cytosol. This is the first identification of a monolignol transporter, closing a crucial gap in our understanding of lignin biosynthesis, which could open new directions for lignin engineering.

PMID:
22704988
DOI:
10.1016/j.cub.2012.04.064
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center