Negatively Regulates Early Rice Seedling Development by Interfering with Starch Metabolism via the GA and Pathways.

encodes SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 14 (SPL14) with a pleiotropic effect on regulating rice development and biotic stress responses. To investigate the role of in early seedling development, we developed a pair of /-NILs and found that seed germination and early seedling growth were retarded in the -NIL. Analysis of the soluble sugar content, activity of amylase, and expression of the -amylase genes revealed that the starch metabolism was weakened in the -NIL germinating seeds. Additionally, the content of bioactive gibberellin (GA) was significantly lower than that in the -NIL seeds at 48 h of imbibition. Meanwhile, the expression of GA synthesis-related gene was downregulated, whereas the expression of GA inactivation-related genes was upregulated in -NIL seeds. In addition, the expression of and was significantly upregulated in -NIL seeds. Using transient dual-luciferase and yeast one-hybrid assays, IPA1 was found to directly activate the expression of and , which would interfere with the binding affinity of GA-induced transcription factor OsGAMYB to inhibit the expression of -amylase genes. In summary, our results suggest that negatively regulates seed germination and early seedling growth by interfering with starch metabolism via the GA and pathways.