The antagonistic crosstalk between gibberellic acid (GA) and abscisic acid (ABA) plays a pivotal role in modulation of seed germination.However,the molecular mechanism of such phytohormone interaction remains largely elusive.The NUCLEAR FACTOR-Y C proteins (NF-YCs),structurally characterized by a histone-fold domain (HFD) and closely related to the core histone H2A,functionally act as one subunit of the NF-Y heterotrimer transcriptional factor that specifically recognizes the CCAAT-box in eukaryotes.Here we show that three Arabidopsis NF-YC homologues NF-YC3,NF-YC4,and NF-YC9 redundantly modulate GA-and ABA-mediated seed germination,contributing to the integration of GA and ABA signaling through directly interacting with RGA-LIKE 2 (RGL2),a key repressor of GA signaling.The NF-YC-RGL2 module targets ABA INSENSITIVE 5 (ABI5),the gene encoding a core component of ABA signaling,via specific CCAAT elements and collectively regulates a set of GA-and ABA-responsive genes,thus control germination.These results illustrate a novel regulatory model that reveals a central molecular link of NF-YC-RGL2-ABI5 in integration of GA and ABA signaling pathways during seed germination,providing a significant mechanistic understanding on how interaction of GA and ABA signaling is fine-tuned in seed germination.