Abstract
In mammals, the electron-transfer flavoprotein (ETF) is a heterodimeric protein composed of two subunits, α and β, which is responsible for the oxidation of at least nine mitochondrial matrix flavoprotein dehydrogenases. Electrons accepted by ETF are further transferred to the main respiratory chain via the electron transfer flavoprotein ubiquinone oxidereductase (ETFQO). There are the unique homologues of two subunits of ETF in Arabidopsis genome. Isolation and characterization of two independent T-DNA insertional Arabidopsis mutants of the ETFβ revealed early death phenotype compared to wild type during extended darkness. Furthermore the etfb mutants demonstrated a significant accumulation of several amino acids, isovaleryl-CoA, and phytanoyl-CoA during dark-induced carbohydrate deprivation. These phenotypic characters of etfb mutants are a phenocopy of those that we observed previously in Arabidopsis etfqo mutants, suggesting functional association between ETF and ETFQO in Arabidopsis, and confirming the essential roles of the ETF/ETFQO electron transfer complex during dark-induced carbohydrate deprivation.
