Catalyzes the isomerization of citrate to isocitrate via cis-aconitate. Contributes to oxidative stress tolerance (PubMed:17013749). Modulates cytosolic citrate metabolism during lipid mobilization. Required during seedling growth (PubMed:25061985). citrate = D-threo-isocitrate Binds 1 [4Fe-4S] cluster per subunit. Carbohydrate metabolism; tricarboxylic acid cycle; isocitrate from oxaloacetate: step 2/2. Monomer (By similarity). Interacts with B'GAMMA in the cytosol (PubMed:25307043). Cytosolic localization in 3-day-old seedlings, but mitochondrial in 10-day-old plantlets. Major aconitase isoenzyme in young seedlings (PubMed:25061985). Expressed in roots, leaves, stems and flowers, and, at low levels, in seeds (PubMed:17437406). Transiently induced during germination. Phosphorylated at Ser-91 in the cytoplasm; this phosphorylation requires the presence of B'GAMMA. Reduced cytosolic and mitochondrial aconitase (ACO) activities by 25 and 55 precent, respectively (PubMed:17013749, PubMed:17437406). Increased tolerance to oxidative stress mediated by paraquat, a superoxide-generating agent (PubMed:17013749). Delayed early seedling growth, altered assimilation of acetate feeding and elevated citrate and malate levels (PubMed:25061985). Belongs to the aconitase/IPM isomerase family. Truncated N-terminus.