Improving the Rice Photosynthetic Efficiency and Yield by Editing via CRISPR/Cas9 System.

Rice ( L.) is an important food crop species in China. Cultivating high-yielding rice varieties that have a high photosynthetic efficiency is an important goal of rice breeding in China. In recent years, due to the continual innovation of molecular breeding methods, many excellent genes have been applied in rice breeding, which is highly important for increasing rice yields. In this paper, the hexokinase gene was knocked out via the CRISPR/Cas9 gene-editing method in the rice varieties Huanghuazhan, Meixiangzhan, and Wushansimiao, and -CRISPR/Cas9 lines were obtained. According to the results of a phenotypic analysis and agronomic trait statistics, the -CRISPR/Cas9 plants presented increased light saturation points, stomatal conductance, light tolerance, photosynthetic products, and rice yields. Moreover, transcriptome analysis showed that the expression of photosynthesis-related genes significantly increased. Taken together, our results revealed that knocking out via the CRISPR/Cas9 gene-editing method could effectively lead to the cultivation of high-photosynthetic efficiency and high-yielding rice varieties. They also revealed the important roles of in the regulation of rice yield and photosynthesis.