A mutation of the mitochondrial ABC transporter Sta1 leads to dwarfism andchlorosis in the Arabidopsis mutant starik

A mutation in the Arabidopsis gene STARIK leads to dwarfism and chlorosis o f plants with an altered morphology of leaf and cell nuclei. We show that t he STARIK gene encodes the mitochondrial ABC transporter Stal that belongs to a subfamily of Arabidopsis half-ABC transporters. The severity of the st arik phenotype is suppressed by the ectopic expression of the STA2 homolog; thus, Stal function is partially redundant, Stal supports the maturation o f cytosolic Fe/S protein in Delta atm1 yeast, substituting for the ABC tran sporter Atm1p, Similar to Atm1p-deficient yeast, mitochondria of the starik mutant accumulated more nonheme, nonprotein iron than did wild-type organe lles, We further show that plant mitochondria contain a putative L-cysteine desulfurase. Taken together, our results suggest that plant mitochondria p ossess an evolutionarily conserved Fe/S cluster biosynthesis pathway, which is linked to the intracellular iron homeostasis by the function of Atm1p-l ike ABC transporters.