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Biosynthesis of new divinyl ether oxylipins in Ranunculus plants

2002; Wiley; Volume: 37; Issue: 4 Linguagem: Inglês

10.1007/s1145-002-0911-5

1558-9307

Mats Hámberg,

Botanical Research and Chemistry

Abstract [1‐ 14 C]Linolenic acid was incubated with homogenates of leaves from the aquatic plants Ranunculus lingua (greater spearwort) or R. peltatus (pond water‐crowfoot). Analysis by reversed‐phase high‐performance liquid radiochromatography demonstrated the formation of a new divinyl ether FA, i.e., 12‐[1′( E ), 3′( Z )‐hexadienyloxy]‐9( Z ), 11( Z )‐dodecadienoic acid [11( Z )‐etherolenic acid] as well as a smaller proportion of ω5( Z )‐etherolenic acid previously identified in terrestrial Ranunculus plants. The same divinyl ethers were formed upon incubation of 13( S )‐hydroperoxy‐9( Z ), 11( E ), 15( Z )‐octadecatrienoic acid, a lipoxygenase metabolite of linolenic acid, whereas the isomeric hydroperoxide, 9( S )‐hydroperoxy‐10( E ), 12( Z ), 15( Z )‐octadecatrienoic acid, was not converted into divinyl ethers in R. lingua or R. peltatus . Incubation of [1‐ 14 C]linoleic acid or 13( S )‐hydroperoxy‐9( Z ), 11( E )‐octadecadienoic acid produced the divinyl ether 12‐[1′( E )‐hexenyloxy]‐9( Z ), 11( Z )‐dodecadienoic acid [11( Z )‐etheroleic acid] and a smaller amount of ω5( Z )‐etheroleic acid. The experiments demonstrated the existence in R. lingua and R. peltatus of a divinyl ether synthase distinct from those previously encountered in higher plants and algae.