The expression and methylation of promoters of the genes encoding succinate dehydrogenase, fumarase, and NAD-malate dehydrogenase in maize (Zea maysL.) leaves depending on the light regime were studied. The genes encoding the catalytic subunits of succinate dehydrogenase showed suppression of expression upon irradiation by red light, which was abolished by far-red light. This was accompanied by an increase in promoter methylation of the geneSdh1-2encoding the flavoprotein subunit A, while methylation was low forSdh2-3encoding the iron-sulfur subunit B under all conditions. The expression ofSdh3-1andSdh4encoding the anchoring subunits C and D was not affected by red light. The expression ofFum1encoding the mitochondrial form of fumarase was regulated by red and far-red light via methylation of its promoter. Only one gene encoding the mitochondrial NAD-malate dehydrogenase gene (mMdh1) was regulated by red and far-red light, while the second gene (mMdh2) did not respond to irradiation, and neither gene was controlled by promoter methylation. It is concluded that the dicarboxylic branch of the tricarboxylic acid cycle is regulated by light via the phytochrome mechanism, and promoter methylation is involved with the flavoprotein subunit of succinate dehydrogenase and the mitochondrial fumarase.