Jing-Ke Weng, Xu Li, Jake Stout, and Clint Chapple*
-Author Affiliations
Department of Biochemistry, Purdue University, 175 South University Street, West Lafayette, IN 47907
Edited by Richard A. Dixon, The Samuel Roberts Noble Foundation, Ardmore, OK, and approved April 1, 2008 (received for review February 20, 2008)
Abstract
Lycophytes arose in the early Silurian (≈400 Mya) and represent a major lineage of vascular plants that has evolved in parallel with the ferns, gymnosperms, and angiosperms. A hallmark of vascular plants is the presence of the phenolic lignin heteropolymer in xylem and other sclerified cell types. Although syringyl lignin is often considered to be restricted in angiosperms, it has been detected in lycophytes as well. Here we report the characterization of a cytochrome P450-dependent monooxygenase from the lycophyte Selaginella moellendorffii. Gene expression data, cross-species complementation experiments, and in vitroenzyme assays indicate that this P450 is a ferulic acid/coniferaldehyde/coniferyl alcohol 5-hydroxylase (F5H), and is capable of diverting guaiacyl-substituted intermediates into syringyl lignin biosynthesis. Phylogenetic analysis indicates that the Selaginella F5H represents a new family of plant P450s and suggests that it has evolved independently of angiosperm F5Hs.
convergent evolution DFRC F5H P450 Selaginella
Footnotes
*To whom correspondence should be addressed. E-mail: chapple@purdue.edu
Author contributions: J.-K.W. and C.C. designed research; J.-K.W., X.L., and J.S. performed research; and J.-K.W. and C.C. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
© 2008 by The National Academy of Sciences of the USA
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