Fig. 1. Grain protein characteristics of rice varieties Naveen (NV) and CR Dhan 310 (CRD310). A, Percentage of grain protein content (GPC) and protein fraction estimated in dehusked grain samples of rice varieties NV and CRD310. B, Amino acid profile in dehusked grain samples of NV and CRD310. HIS, Histidine; SER, Serine; ARG, Arginine; GLY, Glycine; ASP, Aspartic acid; GLU, Glutamic acid; THR, Threonine; ALA, Alanine; PRO, Proline; CYS, Cysteine; LYS, Lysine; TYR, Tyrosine; MET, Methionine; VAL, Valine; ILEU, Isoleucine; LEU, Leucine; PHE, Phenylalanine. C. Volcano plot showing the variability of protein abundance in high-protein rice CRD310 and control NV. D-F, Functional classification of differentially abundant proteins (DAPs) between high-protein variety CRD310 and low-protein recurrent parent NV based on molecular functions (D), biological processes (E), and biochemical pathways (F).

Fig. 2. Protein interactions and differential expression in grains of CR Dhan 310 (CRD310) compared with Naveen (NV). A-D, Protein-protein interactions network constructed using STRING database among storage protein (A), transcriptional factors (B), proteins in amino acid metabolism (C), and chaperons (D) which are expressed higher in grains of high protein rice variety CRD310 compared with low protein rice, NV. E-G, Differential RNA expression in high-protein rice CRD310 in comparison with NV for genes related to N-metabolism, including glutamate dehydrogenase 3 (GD3, E), glutamate synthase 2 (GS2, F), and tryptophan aminotransferase 1 (TA1, G) from collected grain samples at different stages. ML, Milky stage; SD, Soft dough stage; D, Dough stage; HD, Hard dough stage; YR, Yellow ripening stage.