The antagonistic crosstalk between gibberellic acid (GA) and abscisic acid (ABA) plays a pivotal role in the modulation of seed germination. However, the molecular mechanism of such phytohormone interaction remains largely elusive. Here we show that three Arabidopsis NUCLEAR FACTOR-Y C (NF-YC) homologues NF-YC3, NF-YC4 and NF-YC9 redundantly modulate GA- and ABA-mediated seed germination. These NF-YCs interact with the DELLA protein RGL2, a key repressor of GA signalling. The NF-YC-RGL2 module targets ABI5, a gene encoding a core component of ABA signalling, via specific CCAAT elements and collectively regulates a set of GA- and ABA-responsive genes, thus controlling germination. These results suggest that the NF-YC-RGL2-ABI5 module integrates GA and ABA signalling pathways during seed germination.

中文翻译：

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NF-YC-RGL2模块整合了GA和ABA信号，以调节拟南芥中的种子发芽。

赤霉素（GA）和脱落酸（ABA）之间的拮抗作用在调节种子发芽中起关键作用。但是，这种植物激素相互作用的分子机制仍然很难捉摸。在这里，我们显示了三个拟南芥核因子-Y C（NF-YC）同源物NF-YC3，NF-YC4和NF-YC9冗余地调节了GA和ABA介导的种子发芽。这些NF-YC与DELLA蛋白RGL2（GA信号的关键阻遏物）相互作用。NF-YC-RGL2模块通过特定的CCAAT元件靶向ABI5（一种编码ABA信号转导的核心成分的基因），并共同调节一组GA和ABA响应基因，从而控制发芽。这些结果表明，NF-YC-RGL2-ABI5模块在种子发芽过程中整合了GA和ABA信号通路。