Knockout of OsGAPDHC7 Gene Encoding Cytosolic Glyceraldehyde-3-Phosphate Dehydrogenase Affects Energy Metabolism in Rice Seeds

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a major glycolytic enzyme that plays an important role in several cellular processes, including plant hormone signaling, plant development, and transcriptional regulation. In this study, we divided it into four groups through structural analysis of eight <i>GAPDH</i> genes identified in the rice genome. Among them, the expression level of five genes of cytosolic <i>GAPDH</i> was shown to be different for each organ. The mutation induction of the <i>GAPDHC7</i> gene by the CRISPR/Cas9 system revealed that the 7 bp and 2 bp deletion, early end codon, was used in protein production. In addition, the selected mutants showed lower plant heights compared to the wild-type plants. To investigate the effect on carbohydrate metabolism, the expression of the genes of starch-branched enzyme I (<i>SbeI</i>), sucrose synthase (SS), and 3-phosphoglycer phosphokinase (PGK) increased the expression of the <i>SBeI</i> gene threefold in the knockout lines compared to the wild-type (WT) plant, while the expression of the <i>SS</i> and <i>PGK</i> genes decreased significantly. And the starch and soluble sugar content of the knockout lines increased by more than 60% compared to the WT plant. Also, the free amino acid content was significantly increased in the Gln and Asn contents of the knockout lines compared to the WT plants, while the contents of Gly and Ser were decreased. Our results suggest that <i>OsGAPDHC7</i> has a great influence on energy metabolism, such as pre-harvested sprouting and amino acid content.