Tetrapyrrole molecules play essential roles in plant cells, such as chlorophyll, which is involved in photosynthesis, heme, which is involved in redox and electron transport reactions, and bilin, which is the chromophore of photoreceptors. Our laboratory has elucidated the control mechanism of the tetrapyrrole synthesis system and conducted detailed analysis of the functions of each isozyme. Furthermore, by comprehensively controlling the expression of tetrapyrrole biosynthesis and photosynthesis-related genes, we have succeeded in forming chloroplasts in roots, a non-photosynthetic tissue.