PMID:26889912

Citation	Fromm, S, Braun, HP and Peterhansel, C' (2016) Mitochondrial gamma carbonic anhydrases are required for complex I assembly and plant reproductive development. New Phytol. '
Abstract	Complex I of the mitochondrial electron transport chain (mETC) in plants contains an extra domain that is made up from proteins homologous to prokaryotic gamma-carbonic anhydrases (γCA). This domain has been suggested to participate in complex I assembly or to support transport of mitochondrial CO2 to the chloroplast. Here, we generated mutants lacking CA1 and CA2 - two out of three CA proteins in Arabidopsis thaliana. Double mutants were characterized at the developmental and physiological levels. Furthermore, the composition and activity of the mETC were determined, and mutated CA versions were used for complementation assays. 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 II and complex IV were upregulated concomitant with increased oxygen consumption in mitochondrial respiration. Ectopic expression of inactive CA variants was sufficient to complement the mutant phenotype. Data indicate that CA proteins are structurally required for complex I assembly and that reproductive development is dependent on the presence of complex I.
Links	PubMed Online version:10.1111/nph.13886
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ARATH:GCA2		GO:0005747: mitochondrial respiratory chain complex I	ECO:0000314:		C		Figure 1d	complete CACAO 11799
ARATH:GCA2		GO:2000375: negative regulation of oxygen metabolic process	ECO:0000316:	UniProtKB:Q9FWR5	P		Figure 5 shows that a double mutation in CA1 and CA2 result in increased oxygen consumption.	complete CACAO 11800
ARATH:GCA2		GO:1904959: regulation of cytochrome-c oxidase activity	ECO:0000316:	UniProtKB:Q9FWR5	P		Figure 4d shows that a double mutation in ca1 and ca2 drastically increase cytochrome-c oxidase activity. This suggests that ca2 along with ca1 negatively regulates cytochrome-c oxidase activity	complete CACAO 11804
ARATH:GCA1		GO:2000375: negative regulation of oxygen metabolic process	ECO:0000316:	UniProtKB:Q9C6B3	P		Figure 5 shows that a double mutation in ca1 and ca2 increases energy consumption. This suggests that ca1 negatively regulate oxygen consumption.	complete CACAO 11808
ARATH:GCA1		GO:1904959: regulation of cytochrome-c oxidase activity	ECO:0000316:	UniProtKB:Q9C6B3	P		Figure 4d shows that when a double mutation in ca1 and ca2 occurs, cytochrome-c oxidase activity increases drastically. Thus, the data suggests that ca1 negatively regulates cytochrome-c oxidase activity	complete CACAO 11810

References

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