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The metabolic acclimation of Arabidopsis thaliana to arsenate is sensitized by the loss of mitochondrial LIPOAMIDE DEHYDROGENASE2, a key enzyme in oxidative metabolism
Author(s) -
CHEN WEIHUA,
TAYLOR NICOLAS L.,
CHI YINGJUN,
MILLAR A. HARVEY,
LAMBERS HANS,
FINNEGAN PATRICK M.
Publication year - 2014
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12187
Subject(s) - arsenite , arsenate , biochemistry , mitochondrion , oxidative phosphorylation , arabidopsis thaliana , biology , pyruvate dehydrogenase lipoamide kinase isozyme 1 , mutant , chemistry , dehydrogenase , enzyme , branched chain alpha keto acid dehydrogenase complex , arsenic , gene , organic chemistry
Mitochondrial lipoamide dehydrogenase is essential for the activity of four mitochondrial enzyme complexes central to oxidative metabolism. The reduction in protein amount and enzyme activity caused by disruption of mitochondrial LIPOAMIDE DEHYDROGENASE2 enhanced the arsenic sensitivity of Arabidopsis thaliana . Both arsenate and arsenite inhibited root elongation, decreased seedling size and increased anthocyanin production more profoundly in knockout mutants than in wild‐type seedlings. Arsenate also stimulated lateral root formation in the mutants. The activity of lipoamide dehydrogenase in isolated mitochondria was sensitive to arsenite, but not arsenate, indicating that arsenite could be the mediator of the observed phenotypes. Steady‐state metabolite abundances were only mildly affected by mutation of mitochondrial LIPOAMIDE DEHYDROGENASE2 . In contrast, arsenate induced the remodelling of metabolite pools associated with oxidative metabolism in wild‐type seedlings, an effect that was enhanced in the mutant, especially around the enzyme complexes containing mitochondrial lipoamide dehydrogenase. These results indicate that mitochondrial lipoamide dehydrogenase is an important protein for determining the sensitivity of oxidative metabolism to arsenate in Arabidopsis .