Enhancing carotenoid biosynthesis in rice endosperm. (a) Schematic representation of the recombinant vectors used for rice transformation. Upper: PC construction containing two genes; Lower: HPC construction containing three genes. (b) Western blot analyses of PC and HPC transgenic seed proteins. W, wild‐type; 1, 2 and 3, different lines with the HPC construction containing three genes; 4, 5 and 6, different lines with the PC construction containing two genes. (c) Genomic Southern blot analyses of HPC (1, 2) and PC (3, 4) transgenic rice plants.(d) Seed carotenoid content and composition of PC and HPC transgenic rice plants (μg/g dry weight) and comparison of representative seed colour phenotypes among nontransgenic wild‐type (W) rice and independent PC and HPC transgenic rice lines at the T4 generation. (e) Expression of endogenous carotenogenic genes in transgenic rice endosperm. Relative transcript levels of endogenous genes in T4 rice endosperms at 25 DAP expressing different transgenic combinations. Values are the means ± SD of three quantitative real‐time PCR replicates. (f) The agronomic traits of PC (1,2,3) and HPC (4,5,6) transgenic rice plants. (g) Scanning electron microscope images of transverse sections of mature rice seeds. W: wild‐type; PC: expressing ZmPSY1 and PaCRTI; HPC: expressing tHMG1, ZmPSY1 and PaCRTI. Scale bars: 50 μm.