Poster: Metabolic Engineering

Abs # 1013: Disruption of plE2, the gene for the E2 subunit of the plastid pyruvate dehydrogenase complex, in arabidopsis causes an early embryo lethal phenotype

Presenter:	Lin, Ming , minglin@iastate.edu
Authors	Lin, Ming  (A)   Behal, Robert H (A)   Oliver, David J (A)
Affiliations:	(A): Iowa State University

The pyruvate dehydrogenase multienzyme complex is the major source of acetyl-CoA formation in the plastids of plants and is composed of multiple copies of four different subunits, E1(E1a,E1b) E2, and E3. A T-DNA insertion into the gene for the plastidic E2 (dihydrolipoyl acetyltransferase) subunit, plE2, of the complex in Arabidopsis destroys the expression of that gene. The resulting mutation has no apparent phenotype in the heterozygous state, but the homozygous mutation is lethal. Haploid sperm and eggs which contain only the disrupted plE2 gene function normally resulting in the formation of an embryo that is homozygous for the mutation. This embryo only develops to an early stage before the development arrests resulting in an early embryo lethal phenotype. While the mutation could not be complemented using the cDNA for the plE2 gene under control of the 35S, the AtSERK1, or the napin promoter, it could be complemented using the endogenous plE2 promoter to drive expression of the plE2 cDNA. This cerifies the essential nature of the plastidic pyruvate dehydrogenase complex and its role in embryo formation.