This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 148/3/1721    most recent pp.108.125757v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Li, J. Articles by Halkier, B. A. Search for Related Content PubMed PubMed Citation Articles by Li, J. Articles by Halkier, B. A. Agricola Articles by Li, J. Articles by Halkier, B. A. Related Collections Biology of Transpiration

SYSTEMS BIOLOGY, MOLECULAR BIOLOGY, AND GENE REGULATION

Subclade of Flavin-Monooxygenases Involved in Aliphatic Glucosinolate Biosynthesis^1,[W]

Plant Biochemistry Laboratory, Department of Plant Biology and Villum Kann Rasmussen Research Centre for Pro-Active Plants, Faculty of Life Sciences, University of Copenhagen, DK–1871 Frederiksberg C, Denmark (J.L., B.G.H., B.A.H.); and Department of Plant Sciences, University of California, Davis, California 95616–8780 (J.A.O., D.J.K.)

Glucosinolates (GSLs) are amino acid-derived secondary metabolites with diverse biological activities dependent on chemical modifications of the side chain. We previously identified the flavin-monooxygenase FMO_GS-OX1 as an enzyme in the biosynthesis of aliphatic GSLs in Arabidopsis (Arabidopsis thaliana) that catalyzes the S-oxygenation of methylthioalkyl to methylsulfinylalkyl GSLs. Here, we report the fine mapping of a quantitative trait locus for the S-oxygenating activity in Arabidopsis. In this region, there are three FMOs that, together with FMO_GS-OX1 and a fifth FMO, form what appears to be a crucifer-specific subclade. We report the identification of these four uncharacterized FMOs, designated FMO_GS-OX2 to FMO_GS-OX5. Biochemical characterization of the recombinant protein combined with the analysis of GSL content in knockout mutants and overexpression lines show that FMO_GS-OX2, FMO_GS-OX3, and FMO_GS-OX4 have broad substrate specificity and catalyze the conversion from methylthioalkyl GSL to the corresponding methylsulfinylalkyl GSL independent of chain length. In contrast, FMO_GS-OX5 shows substrate specificity toward the long-chain 8-methylthiooctyl GSL. Identification of the FMO_GS-OX subclade will generate better understanding of the evolution of biosynthetic activities and specificities in secondary metabolism and provides an important tool for breeding plants with improved cancer prevention characteristics as provided by the methylsulfinylalkyl GSL.

² These authors contributed equally to the article.

³ Present address: Center for Microbial Biotechnology, Department of Systems Biology, Technical University of Denmark, DK–2800 Kgs. Lyngby, Denmark.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Barbara Ann Halkier (bah{at}life.ku.dk).

^[W] The online version of this article contains Web-only data.

www.plantphysiol.org/cgi/doi/10.1104/pp.108.125757

^* Corresponding author; e-mail bah{at}life.ku.dk.

Received July 7, 2008; accepted September 14, 2008; published September 17, 2008.

This article has been cited by other articles:

				DanielJ. Kliebenstein Advancing Genetic Theory and Application by Metabolic Quantitative Trait Loci Analysis PLANT CELL, June 1, 2009; 21(6): 1637 - 1646. [Abstract] [Full Text] [PDF]

				T. Gigolashvili, R. Yatusevich, I. Rollwitz, M. Humphry, J. Gershenzon, and U.-I. Flugge The Plastidic Bile Acid Transporter 5 Is Required for the Biosynthesis of Methionine-Derived Glucosinolates in Arabidopsis thaliana PLANT CELL, June 1, 2009; 21(6): 1813 - 1829. [Abstract] [Full Text] [PDF]