Carbon flux repartitioning at mid-stage meiosis. Pie charts show fractions of acetate-derived (blue) and glycogen-derived (red) carbon found in the metabolites. Asterisks indicate that these fractions were calculated (see Additional file 2). Metabolic flux analysis quantified the relative contribution of glycogen- and acetate-derived carbon to spore wall formation. (The fraction of acetate-derived carbon assimilated via Krebs and glyoxylate cycle was not quantified). Thickness of the arrows and depicted values correspond to the carbon flux over each reaction normalized to the overall carbon flux into spore wall formation (upper value = carbon flux derived from glycogen; lower value = carbon flux derived from acetate). Dashed and black lines indicate that no estimation of the exact flux can be provided. (Abbreviations: 6PG = 6P-gluconate, Sed-7P = sedoheptulose-7P, 2-OG = 2-oxoglutarate).