Evidence for oxylipin synthesis and induction of a new polyunsaturated fatty acid hydroxylase activity in Chondrus crispus in response to methyljasmonate.
Signaling cascades involving oxygenated derivatives (oxylipins) of polyunsaturated fatty acids (PUFAs) are known to operate in response to external stimuli. The marine red alga Chondrus crispus uses both oxygenated derivatives of C18 (octadecanoids) and C20 (eicosanoids) PUFAs as developmental or defense hormones. The present study demonstrates that methyljasmonate (MeJA) triggers a cascade of oxidation of PUFAs leading to the synthesis of prostaglandins and other oxygenated fatty acids. As a result of a lipoxygenase-like activation, MeJA induces a concomitant accumulation of 13-hydroxy-9Z,11E-octadecadienoic acid (13-HODE) and 13-oxo-9Z,11E-octadecadienoic acid (13-oxo-ODE) in a dose-dependent manner in C. crispus. Furthermore, MeJA increases the level of mRNA encoding a gluthatione S-transferase and induces the activity of a new enzyme catalyzing the regio- and stereoselective bisallylic hydroxylation of polyunsaturated fatty acids from C(18) to C(22). The enzyme selectively oxidized the omega minus 7 carbon position (omega-7) and generated the stereoselective (R)-hydroxylated metabolites with a large enantiomeric excess. The enzyme specificity for the fatty acid recognition was not dependent of the position of double bonds but at least requires a methylene interrupted double bond 1,4-pentadiene motif involving the omega-7 carbon.
Gaquerel
Emmanuel
E
Centre National de la Recherche Scientifique, Université Pierre et Marie Curie-Paris6, Laboratoire International Associé-Dispersal and Adaptation in Marine Species, Unité Mixte de Recherche 7139, Station Biologique, F-29682 Roscoff Cedex, France.
Hervé
Cécile
C
Labrière
Christophe
C
Boyen
Catherine
C
Potin
Philippe
P
Salaün
Jean-Pierre
JP
D000085:Acetates / Q000494:pharmacology*; D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism*; D044723:Chondrus / Q000187:drug effects / Q000201:enzymology*; D003517:Cyclopentanes / Q000494:pharmacology*; D017931:DNA Primers; D015232:Dinoprostone / Q000031:analogs & derivatives / Q000096:biosynthesis; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D019787:Linoleic Acid / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D054883:Oxylipins; D016133:Polymerase Chain Reaction; D011454:Prostaglandins A / Q000096:biosynthesis; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D013379:Substrate Specificity
D000085:Acetates; D020418:Algal Proteins; D003517:Cyclopentanes; D017931:DNA Primers; D005231:Fatty Acids, Unsaturated; D054883:Oxylipins; D011454:Prostaglandins A; C026346:15-ketoprostaglandin E2; D012313:RNA; C011006:jasmonic acid; C072239:methyl jasmonate; D019787:Linoleic Acid; D006899:Mixed Function Oxygenases; C100008:prostaglandin A2; D015232:Dinoprostone