Mitochondrial gamma carbonic anhydrases are required for complex I assembly and plant reproductive development

作者：Fromm Steffanie; Braun Hans Peter; Peterhansel Christoph

来源：NEW PHYTOLOGIST, 2016, 211(1): 194-207.

DOI：10.1111/nph.13886

<jats:title>Summary</jats:title><jats:p>
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<jats:list-item><jats:p>Complex I of the mitochondrial electron transport chain (<jats:styled-content style="fixed-case">mETC</jats:styled-content>) in plants contains an extra domain that is made up from proteins homologous to prokaryotic gamma‐carbonic anhydrases (γ<jats:styled-content style="fixed-case">CA</jats:styled-content>). This domain has been suggested to participate in complex I assembly or to support transport of mitochondrial <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub> to the chloroplast.</jats:p></jats:list-item>

<jats:list-item><jats:p>Here, we generated mutants lacking <jats:styled-content style="fixed-case">CA</jats:styled-content>1 and <jats:styled-content style="fixed-case">CA</jats:styled-content>2 – two out of three <jats:styled-content style="fixed-case">CA</jats:styled-content> proteins in <jats:italic>Arabidopsis thaliana</jats:italic>. Double mutants were characterized at the developmental and physiological levels. Furthermore, the composition and activity of the <jats:styled-content style="fixed-case">mETC</jats:styled-content> were determined, and mutated <jats:styled-content style="fixed-case">CA</jats:styled-content> versions were used for complementation assays.</jats:p></jats:list-item>

<jats:list-item><jats:p>Embryo development of double mutants was strongly delayed and seed development stopped before maturation. Mutant plants could only be rescued on sucrose media, showed severe stress symptoms and never produced viable seeds. By contrast, callus cultures were only slightly affected in growth. Complex I was undetectable in the double mutants, but complex <jats:styled-content style="fixed-case">II</jats:styled-content> and complex <jats:styled-content style="fixed-case">IV</jats:styled-content> were upregulated concomitant with increased oxygen consumption in mitochondrial respiration. Ectopic expression of inactive <jats:styled-content style="fixed-case">CA</jats:styled-content> variants was sufficient to complement the mutant phenotype.</jats:p></jats:list-item>

<jats:list-item><jats:p>Data indicate that <jats:styled-content style="fixed-case">CA</jats:styled-content> proteins are structurally required for complex I assembly and that reproductive development is dependent on the presence of complex I.</jats:p></jats:list-item>
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• 出版日期2016-7