Figure 5.

Expression of Calvin cycle and pentose phosphate pathway genes. The Calvin cycle (green) and pentose phosphate pathway (orange) interlock; because their shared reactions (purple) run in opposite directions, the cycles cannot productively run at the same time. Gas shock expression data (thumbnail plots) for each gene in these pathways suggests that, as expected, CO₂ starvation broadly downregulates the carbon-fixing Calvin cycle, while leaving the reductive pentose phosphate pathway largely intact. Data points are the geometric means of two biological replicates. Fold change is relative to t=0 for each condition. All thumbnail plots share the same layout and axis scales; for details, see sample plot at lower right. Data in sample plot (see Key) is simulated for illustration. The region between each time course and the baseline used for significance testing (for the air control, expression at t=0; for experimental conditions, the parallel time course in air) is shaded according to the outcome of that test: a significant change in expression in air with respect to t=0, blue; a significantly different time course in an experimental condition than in air, red; no significant effect, gray. Genes: cbbA, fructose-1,6-bis-P/sedoheptulose-1,7-bis-P aldolase; cp12, regulator CP12; gap2, glyceraldehyde-3-phosphate dehydrogenase; glpX, fructose-1,6/sedoheptulose-1,7-bisphosphatase; gnd, 6-phosphogluconate dehydrogenase; opcA, putative glucose-6-phosphate dehydrogenase effector; pgi, P-glucose isomerase; pgk, P-glycerate kinase; pgl, 6-P-gluconolactonase; prkB, P-ribulokinase; rbcLS, ribulose-1,5-bis-P carboxylase/oxygenase large and small subunits; rbcR, putative Rubisco transcriptional regulator; rpe, ribulose-5-P epimerase; rpiA, ribulose-5-P isomerase; talB, transaldolase; tktA, transketolase; tpi, triose-P isomerase; zwf, glucose-6-phosphate dehydrogenase. Substrates: BPG, 2,3-bis-P-glycerate; DHAP, dihydroxyacetone P; E4P, erythrose-4-P; FBP, fructose-1,6-bis-P; F6P, fructose-6-P; GAP, glyceraldehyde-3-P; G6P, glucose-6-P; PGA, 3-P-glyceric acid; R5P, ribose-5-P; RuBP, ribulose-1,5-bis-P; Ru5P, ribulose-5-P; SBP, sedoheptulose-1,7-bis-P; 6PG, 6-P-gluconate; 6PGL, 6-P-gluconolactone; S7P, sedoheptulose-7-P; and X5P, xylulose-5-P.