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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #179100
Title: ARABIDOPSIS PLANTS WITH AN INDUCED RNAI HAIRPIN OR A CONSTITUTIVELY EXPRESSED DOMINANT NEGATIVE ALLELE OF THE LCB2 GENE HAVE ALTERED SPHINGOLIPID CONTENT

Author
item Dietrich, Charles
item CHEN, MING - DONALD DANFORTH PLANT SCI
item Cahoon, Edgar

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2005
Publication Date: 3/18/2005
Citation: Dietrich, C.R., Chen, M., Cahoon, E.B. 2005. Arabidopsis plants with an induced rnai hairpin or a constitutively expressed dominant negative allele of the lcb2 gene have altered sphingolipid content [abstract]. 2005 Midwest American Society of Plant Biologists Sectional Meeting. p. 23.

Interpretive Summary:

Technical Abstract: The first step in sphingolipid biosynthesis is the condensation of palmitoyl-CoA and serine. This reaction is catalyzed by serine palmitoyltransferase (SPT), a pyridoxal 5’ phosphate-dependent enzyme. In yeast, SPT is believed to be a heterodimer consisting of the polypeptides LCB1 and LCB2. Arabidopsis contains one LCB1 homolog and two LCB2 homologs (LCB2a and LCB2b). To help determine the function of sphingolipids in plant growth and development, Arabidopsis T-DNA lines carrying genetic mutations in the AtLCB2 genes were obtained and characterized. A single mutation in either AtLCB2 gene had no effect on plant development, but double mutants of the two AtLCB2 genes were not viable. As an alternative approach for obtaining an AtLCB2 double mutant, an RNAi hairpin cassette to the AtLCB2a gene was placed under the control of an inducible promoter in an AtLCB2b homozygous mutant. Chemical induction of the hairpin resulted in silencing of the AtLCB2a gene, which in turn blocked all LCB2-mediated sphingolipid synthesis and resulted in gradual plant lethality. Arabidopsis lines with non-lethal reductions in sphingolipid content were obtained by over-expression of an AtLCB2a gene containing a mutation within the pyridoxal 5’ phosphate binding domain. These plants display distinct growth phenotypes and altered responses to various stresses. It is anticipated that the detailed characterization of these plants will provide a further understanding of the role of sphingolipids in plant growth and development.