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The mitochondrial electron transfer flavoprotein complex is essential for survival of Arabidopsis in extended darkness
Author(s) -
Ishizaki Kimitsune,
Schauer Nicolas,
Larson Tony R.,
Graham Ian A.,
Fernie Alisdair R.,
Leaver Christopher J.
Publication year - 2006
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2006.02826.x
Subject(s) - arabidopsis , biology , flavoprotein , mutant , biochemistry , arabidopsis thaliana , protein subunit , gene , genetics , enzyme
Summary In mammals, the electron transfer flavoprotein (ETF) is a heterodimeric protein composed of two subunits, α and β , that 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 ETF ubiquinone oxide reductase (ETFQO). Sequence analysis of the unique Arabidopsis homologues of two subunits of ETF revealed their high similarity to both subunits of the mammalian ETF. Yeast two‐hybrid experiments showed that the Arabidopsis ETF α and ETF β can form a heteromeric protein. Isolation and characterization of two independent T‐DNA insertional Arabidopsis mutants of the ETF β gene revealed accelerated senescence and early death compared to wild‐type during extended darkness. Furthermore in contrast to wild‐type, the etfb mutants demonstrated a significant accumulation of several amino acids, isovaleryl CoA and phytanoyl CoA during dark‐induced carbohydrate deprivation. These phenotypic characteristics of etfb mutants are broadly similar to 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 in the catabolism of leucine and involvement in the chlorophyll degradation pathway activated during dark‐induced carbohydrate deprivation.