Poster: Hormones

Abs # 583: Jasmonate metabolism in tobacco BY-2 cells

Presenter:	Swiatek, Agnieszka , agnieszka.swiatek@ua.ac.be
Authors	Swiatek, Agnieszka  (A)   Van Onckelen, Harry  (A)
Affiliations:	(A): University Of Antwerp

Jasmonates play a crucial role in plant development and defense responses. The balance between their biosynthesis and catabolism determines their endogenous levels. While the biosynthetic pathway of jasmonic acid is fully resolved, with the major enzymes characterized genetically and biochemically, its metabolic fate is less studied. Our studies were focused on the uptake and metabolism of jasmonic acid and methyl jasmonate in tobacco BY-2 cells. Treatment of the cell culture with jasmonic acid results in its reversible incorporation in mono-and disaccharide esters and further hydroxylation at C11 or C12 position. Methyl jasmonate, upon its hydrolysis to jasmonic acid, underwent a similar chain of conversions as jasmonic acid. Based on the inter-conversions between subsequent metabolites, we suggest the initial steps of the catabolic pathway of jasmonic acid in tobacco BY-2. We also determined the biological activity of the metabolites of jasmonic acid and found out that, similarly to authentic jasmonic acid and its precursor, a-linolenic acid, they affect sugar metabolism. On the other hand it was shown that only jasmonic acid or methyl jasmonate, probably upon conversion to jasmonic acid, were able to induce cell cycle arrest in synchronized BY-2.