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Linolenate 9R-Dioxygenase and Allene Oxide Synthase Activities of Lasiodiplodia theobromae.
MedLine Citation:
PMID:  22048860     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Jasmonic acid (JA) is synthesized from linolenic acid (18:3n-3) by sequential action of 13-lipoxygenase, allene oxide synthase (AOS), and allene oxide cyclase. The fungus Lasiodiplodia theobromae can produce large amounts of JA and was recently reported to form the JA precursor 12-oxophytodienoic acid. The objective of our study was to characterize the fatty acid dioxygenase activities of this fungus. Two strains of L. theobromae with low JA secretion (~0.2 mg/L medium) oxygenated 18:3n-3 to 5,8-dihydroxy-9Z,12Z,15Z-octadecatrienoic acid as well as 9R-hydroperoxy-10E,12Z,15Z-octadecatrienoic acid, which was metabolized by an AOS activity into 9-hydroxy-10-oxo-12Z,15Z-octadecadienoic acid. Analogous conversions were observed with linoleic acid (18:2n-6). Studies using [11S-(2)H]18:2n-6 revealed that the putative 9R-dioxygenase catalyzed stereospecific removal of the 11R hydrogen followed by suprafacial attack of dioxygen at C-9. Mycelia from these strains of L. theobromae contained 18:2n-6 as the major polyunsaturated acid but lacked 18:3n-3. A third strain with a high secretion of JA (~200 mg/L) contained 18:3n-3 as a major fatty acid and produced 5,8-dihydroxy-9Z,12Z,15Z-octadecatrienoic acid from added 18:3n-3. This strain also lacked the JA biosynthetic enzymes present in higher plants.
Authors:
Fredrik Jernerén; Felipe Eng; Mats Hamberg; Ernst H Oliw
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-11-3
Journal Detail:
Title:  Lipids     Volume:  -     ISSN:  1558-9307     ISO Abbreviation:  -     Publication Date:  2011 Nov 
Date Detail:
Created Date:  2011-11-3     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0060450     Medline TA:  Lipids     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Department of Pharmaceutical Biosciences, Uppsala Biomedical Center, Uppsala University, P.O. Box 591, 751 24, Uppsala, Sweden.
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