Characterization of Arabidopsis mutant with inactivated gene coding for Fe-S subunit of mitochondrial respiratory chain complex I

The mutant line of Arabidopsis thaliana obtained by insertion mutagenesis of fro gene (at5g67590) encoding the 18-kD Fe-S subunit of mitochondrial respiratory chain complex I was characterized. The homozygous plants carrying the insert were selected by PCR genotyping. The absence in these plants of transcripts corresponding in size to the fro gene was confirmed by gene expression analysis. The homozygous plants obtained were characterized by several phenotypic features, such as late seed germination, retarded growth and development, the increased number and deep-green color of leaves. At variance with earlier data obtained for splicing-defective mutants of the Arabidopsis fro gene, the plants obtained in this study did not exhibit a lower resistance to abiotic stresses. Despite complete inactivation of the fro gene, the mutant plants were similar to the wild-type plants in terms of biomass growth and productivity. It is concluded that regulatory systems for gene expression in mutant Arabidopsis plants with impaired respiratory complex I are able to largely compensate for the respiratory deficiency at the phenotypic level.