Evaluation of cPGI repression and fertility in Ri-cpgi, cPGI-co, and p35S::cPGI-YFP cpgi-3^(−/−) lines. A, Starch-excess phenotypes in Ri-cpgi lines. Mature, unshaded leaves were harvested at the end of night (EoN) or 8 h into light (8h-L) from 5-week-old plants grown under a 16-h light/8-h dark regime for iodine staining for starch content. Bar = 1 cm. B, The fertility of the indicated plants was evaluated by calculating the percentage of elongated siliques (seed-containing) over the total siliques scored. The percentage mean ± se is plotted, and the percentage mean of each line is indicated (plant n = 3–8). C, Soluble proteins extracted from rosette leaves and inflorescence apices (floral buds in various sizes) of the same plants as indicated were subjected to nondenaturing polyacrylamide gel electrophoresis for the in-gel PGI activity assay. The PGI enzyme activity was shown as a purple band of formazan precipitation on the gel. The activity of plastidial PGI1, endogenous cPGI, and the cPGI-YFP fusion protein was as indicated. D, Immunoblotting assay using the primary antibodies against cPGI. E, After immunoblotting, to show the abundance of loaded proteins, the blot was stained with Ponceau S, showing the major protein band of Rubisco large subunit as a reference; the same blot region is shown as in (D). The molecular mass of protein markers (M) is indicated in kDa at the left. Relative cPGI enzyme activity (C) or cPGI protein abundance (D) to that of WT levels in floral buds was evaluated by ImageJ quantification.