Design C2 rice for increasing carbon fixation and productivity

Photosynthesis is known as a major reaction to capture most of atmospheric CO2 on Earth. Its primary metabolite is C3 carbohydrates, which is used to produce carbohydrates for supporting growth and development. While a primary C2 metabolite, as known as acetyl-coA, is produced via decarboxylation of C3 in which 1/3 of CO2 is released. In addition, rubisco oxygenation causes 25% carbon loss via recycling glycolate (C2) to glycerate (C3) pathway. The synthetic McG cycle can convert a PEP (C3) and a CO2 (C1) to form two acetyl-coA or a glycolate to an acetyl-coA without net carbon loss. Introduction of complete McG cycle into Arabidopsis plants targeted to the chloroplasts remarkably increasing their carbon fixation rates, biomasses, seed production, and oil contents in leaves and seeds. Furthermore, the McG plants had higher quantum use efficiency in biochemistry (phiPSII), protein abundance in photosystem, and more thylakoid grana per chloroplast compared to the Arabidposis WT.To study the effects of McG in crop plants, we introduced the McG cycle into rice (Oryza sativa L. ssp Japonica TNG67 and Kitaake). Multiple T0 transgenic rice plants showed higher tiller numbers and contained more lipids in their leaves. Consequently, they produced more grains.