Changing the role of the TCA cycle and of amino acid metabolism. (a) Expression of genes in the TCA cycle, including the glyoxylate shunt. RPKMs of each gene were compared in mock- (gray bars) and pathogen-infected (black bars) leaves. (b) Expression of genes for amino acid metabolism. RPKMs of each gene were compared as in (a). (c) Roles of glyoxylate shunt and amino acid metabolism in the defense response. Upregulation or downregulation of genes is shown on the metabolic map. The glyoxylate shunt pathway of the TCA cycle skips the CO2-generating steps. Subsequently, phenylalanine [Phe] and tyrosine [Tyr] are synthesized through the shikimate pathway. Phe and Tyr are precursors of various flavonoids and isoquinone alkaloids, respectively. Tyr is also a precursor of the sorghum-specific cyanogenic glycoside, dhurrin. Succinate is suppied from glutamate (Glu). Cysteine (Cys) is suppied from Serine (Ser); Cys serves as a precursor for various sulfur-dependent detoxication.