The mitochondrial electron transfer flavoprotein complex is essential for survival of Arabidopsis in extended darkness

TY - JOUR

T1 - The mitochondrial electron transfer flavoprotein complex is essential for survival of Arabidopsis in extended darkness

AU - Ishizaki, Kimitsune

AU - Schauer, Nicolas

AU - Larson, Tony R.

AU - Graham, Ian A.

AU - Fernie, Alisdair R.

AU - Leaver, Christopher J.

N1 - Open access copy available from the journal web site.

PY - 2006/9

Y1 - 2006/9

N2 - In mammals, the electron transfer flavoprotein (ETF) is a heterodimeric protein composed of two subunits, alpha and beta, 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 alpha and ETF beta can form a heteromeric protein. Isolation and characterization of two independent T-DNA insertional Arabidopsis mutants of the ETF beta 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.

AB - In mammals, the electron transfer flavoprotein (ETF) is a heterodimeric protein composed of two subunits, alpha and beta, 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 alpha and ETF beta can form a heteromeric protein. Isolation and characterization of two independent T-DNA insertional Arabidopsis mutants of the ETF beta 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.

KW - Arabidopsis thaliana

KW - electron transfer flavoprotein (ETF)

KW - carbohydrate deprivation

KW - mitochondria

KW - isovaleryl CoA

KW - phytanoyl CoA

KW - ACYL-COA DEHYDROGENASES

KW - UBIQUINONE OXIDOREDUCTASE

KW - RESPIRATORY-CHAIN

KW - GENE-EXPRESSION

KW - ACID CATABOLISM

KW - BETA-OXIDATION

KW - CELL-DEATH

KW - THALIANA

KW - PROTEINS

KW - PLANTS

U2 - 10.1111/j.1365-313X.2006.02826.x

DO - 10.1111/j.1365-313X.2006.02826.x

M3 - Article

SN - 0960-7412

VL - 47

SP - 751

EP - 760

JO - Plant Journal

JF - Plant Journal

IS - 5

ER -