Model map for the role of CIPK9 in regulating seed oil content as well as source and sink organ size. CIPK9 can participate in the regulation of glucose homeostasis. In the cipk9 mutant, the CIPK9 protein loses its function and diminishes the sensitivity to high glucose in plant tissues. Therefore, the cipk9 mutant becomes less sensitive to high glucose, which enhances sucrose and glucose biosynthesis. To reduce the high glucose level, the hormone signaling is triggered, which can enhance the sugar consumption by activating anabolic processes. In the source organs, the enhanced sugar metabolism and improved IAA or GA result in larger leaves and longer siliques. In the sink organs and seed, the synchronically enhanced glucose and sucrose biosynthesis along with improved ABA biosynthesis lead to more active oil metabolism by improving the fatty acid biosynthesis in seeds. ABA, abscisic acid; IAA, indoleacetic acid; GA, gibberellin; FA, fatty acid; PUFA, polyunsaturated fatty acid; MUFA, monounsaturated fatty acid; SPP, SUC-PHOSPHATE PHOSPHATASE; SPS, SUC-PHOSPHATE SYNTHASE; INV, INVERTASE; SUS, SUCROSE SYNTHASE; ABAs, ABA DEFICIENT; ABIs, ABA INSENSITIVE; CIPK9, calcineurin B-like interacting protein kinase 9; HXK1, HEXOKINASE 1; RGS1, regulators of G protein signaling 1.