Abstract:Chlorophyll is an important pigment in rice photosynthesis, and its synthesis determines the efficiency of photosynthesis, ultimately affecting plant yield and quality. In this study, it was found that the glycogen synthase kinase OsGSK2 overexpressed Go-2 plants exhibited a dark green leaf phenotype at heading date. Compared to the wild type, the contents of chlorophyll a, chlorophyll b, and carotenoids in Go-2 plants significantly increased. The observation results of transmission electron microscopy showed that compared to the wild type, the chloroplast thylakoid layers of Go-2 plants increased. Yeast two hybrid "one-to-one" experiment confirmed the interaction between OsGSK2 and the Golden2-Like transcription factor OsGLK1, and further confirmed the interaction between OsGSK2 and OsGLK1 through bimolecular fluorescence complementarity experiments. By detecting dual luciferase activity in rice protoplasts, it was found that compared to single transgenic OsGLK1, co transfection of OsGSK2 and OsGLK1 significantly increased the expression level of downstream target genes. The fluorescence quantitative PCR results showed that compared to the wild-type, the transcription levels of target genes (OsPORB, OsCAO1, LHCB6, etc) directly regulated by OsGLK1 were significantly up-regulated in Go-2 plants. These results provided preliminarily insights on the molecular mechanism of the interaction between OsGSK2 and OsGLK1 in regulating rice chlorophyll synthesis and chloroplast development, extending the molecular function of rice glycogen synthase kinase, enriching the regulation network of rice leaf color, and providing theoretical basis for high photosynthetic molecular breeding in rice.