This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 151/3/1421    most recent pp.109.145094v1 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 CrossRef Google Scholar Articles by Bannenberg, G. Articles by Castresana, C. PubMed PubMed Citation Articles by Bannenberg, G. Articles by Castresana, C. Agricola Articles by Bannenberg, G. Articles by Castresana, C.

DEVELOPMENT AND HORMONE ACTION

Functional Analysis of -DOX2, an Active -Dioxygenase Critical for Normal Development in Tomato Plants^1,[W]

Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain (G.B., M.M., M.J.R., M.A.L., C.C.); Departamento Biología Molecular, Instituto de Investigaciones Biológicas Clemente Estable, 11600 Montevideo, Uruguay (I.P.L.); and Department of Medical Biochemistry and Biophysics, Division of Physiological Chemistry II, Karolinska Institutet, 17177 Stockholm, Sweden (M.H.)

Plant -dioxygenases initiate the synthesis of oxylipins by catalyzing the incorporation of molecular oxygen at the -methylene carbon atom of fatty acids. Previously, -DOX1 has been shown to display -dioxygenase activity and to be implicated in plant defense. In this study, we investigated the function of a second -dioxygenase isoform, -DOX2, in tomato (Solanum lycopersicum) and Arabidopsis (Arabidopsis thaliana). Recombinant Sl-DOX2 and At-DOX2 proteins catalyzed the conversion of a wide range of fatty acids into 2(R)-hydroperoxy derivatives. Expression of Sl-DOX2 and At-DOX2 was found in seedlings and increased during senescence induced by detachment of leaves. In contrast, microbial infection, earlier known to increase the expression of -DOX1, did not alter the expression of Sl-DOX2 or At-DOX2. The tomato mutant divaricata, characterized by early dwarfing and anthocyanin accumulation, carries a mutation at the Sl-DOX2 locus and was chosen for functional studies of -DOX2. Transcriptional changes in such mutants showed the up-regulation of genes playing roles in lipid and phenylpropanoid metabolism, the latter being in consonance with the anthocyanin accumulation. Transgenic expression of At-DOX2 and Sl-DOX2 in divaricata partially complemented the compromised phenotype in mature plants and fully complemented it in seedlings, thus indicating the functional exchangeability between -DOX2 from tomato and Arabidopsis. However, deletion of At-DOX2 in Arabidopsis plants did not provoke any visible phenotypic alteration indicating that the relative importance of -DOX2 in plant physiology is species specific.

² These authors contributed equally to the article.

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: Carmen Castresana (ccastresana{at}cnb.csic.es).

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

www.plantphysiol.org/cgi/doi/10.1104/pp.109.145094

^* Corresponding author; e-mail ccastresana{at}cnb.csic.es.

Received July 21, 2009; accepted September 14, 2009; published September 16, 2009.