This Article Full Text Full Text (PDF) A correction has been published All Versions of this Article: 15/10/2383    most recent tpc.015529v1 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 ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (21) Citing Articles via Google Scholar Google Scholar Articles by Nandi, A. Articles by Shah, J. Search for Related Content PubMed PubMed Citation Articles by Nandi, A. Articles by Shah, J. Agricola Articles by Nandi, A. Articles by Shah, J.

Arabidopsis sfd Mutants Affect Plastidic Lipid Composition and Suppress Dwarfing, Cell Death, and the Enhanced Disease Resistance Phenotypes Resulting from the Deficiency of a Fatty Acid Desaturase

^a Division of Biology, Kansas State University, Manhattan, Kansas 66506
^b Molecular, Cellular, and Developmental Biology Program, Kansas State University, Manhattan, Kansas 66506
^c Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008

² To whom correspondence should be addressed. E-mail shah{at}ksu.edu; fax 785-532-6653

A loss-of-function mutation in the Arabidopsis SSI2/FAB2 gene, which encodes a plastidic stearoyl–acyl-carrier protein desaturase, has pleiotropic effects. The ssi2 mutant plant is dwarf, spontaneously develops lesions containing dead cells, accumulates increased salicylic acid (SA) levels, and constitutively expresses SA-mediated, NPR1-dependent and -independent defense responses. In parallel, jasmonic acid–regulated signaling is compromised in the ssi2 mutant. In an effort to discern the involvement of lipids in the ssi2-conferred developmental and defense phenotypes, we identified suppressors of fatty acid (stearoyl) desaturase deficiency (sfd) mutants. The sfd1, sfd2, and sfd4 mutant alleles suppress the ssi2-conferred dwarfing and lesion development, the NPR1-independent expression of the PATHOGENESIS-RELATED1 (PR1) gene, and resistance to Pseudomonas syringae pv maculicola. The sfd1 and sfd4 mutant alleles also depress ssi2-conferred PR1 expression in NPR1-containing sfd1 ssi2 and sfd4 ssi2 plants. By contrast, the sfd2 ssi2 plant retains the ssi2-conferred high-level expression of PR1. In parallel with the loss of ssi2-conferred constitutive SA signaling, the ability of jasmonic acid to activate PDF1.2 expression is reinstated in the sfd1 ssi2 npr1 plant. sfd4 is a mutation in the FAD6 gene that encodes a plastidic 6-desaturase that is involved in the synthesis of polyunsaturated fatty acid–containing lipids. Because the levels of plastid complex lipid species containing hexadecatrienoic acid are depressed in all of the sfd ssi2 npr1 plants, we propose that these lipids are involved in the manifestation of the ssi2-conferred phenotypes.

This article has been cited by other articles:

				A. C. Chandra-Shekara, S. C. Venugopal, S. R. Barman, A. Kachroo, and P. Kachroo Plastidial fatty acid levels regulate resistance gene-dependent defense signaling in Arabidopsis PNAS, April 24, 2007; 104(17): 7277 - 7282. [Abstract] [Full Text] [PDF]

				G. Bonaventure, X. Bao, J. Ohlrogge, and M. Pollard Metabolic Responses to the Reduction in Palmitate Caused by Disruption of the FATB Gene in Arabidopsis Plant Physiology, July 1, 2004; 135(3): 1269 - 1279. [Abstract] [Full Text] [PDF]

				A. Nandi, R. Welti, and J. Shah The Arabidopsis thaliana Dihydroxyacetone Phosphate Reductase Gene SUPPRESSOR OF FATTY ACID DESATURASE DEFICIENCY1 Is Required for Glycerolipid Metabolism and for the Activation of Systemic Acquired Resistance PLANT CELL, February 1, 2004; 16(2): 465 - 477. [Abstract] [Full Text] [PDF]