The speed of flower opening is closely related to their ornamental period. Ethylene functions as a negative regulator involved in the regulation of the petal expansion process. In this study, we isolated a NF-YC transcription factor gene, RhNF-YC9, from rose petals. RhNF-YC9 expression was induced at the early stages of flower opening but was inhibited by ethylene treatment. Silencing RhNF-YC9 decreased the speed of petal expansion from stage 2 to stage 5. The expressions of 11 cell expansion-related genes involved in cell wall loosening, cell turgor modulation, and cytoskeleton remodeling were significantly down-regulated in RhNF-YC9-silenced petals. We also found that silencing RhNF-YC9 decreased the expression of gibberellin acid (GA) biosynthetic gene RhGA20ox while significantly increasing the transcripts of GA catabolic gene RhGA2ox, reducing the accumulation of GA₄ and GA₇. The influence of ethylene treatment on the expression of RhGA20ox and RhGA2ox showed the same trend. These results together suggested that RhNF-YC9 positively regulated the speed of petal expansion and mediated the crosstalk between ethylene and GA. Our findings revealed a new insight into the function of NF-YC transcription factors involved in ethylene-regulated petal expansion.

开花的速度与其观赏期密切相关。乙烯充当负调节剂，参与花瓣膨胀过程的调节。在这项研究中，我们从玫瑰花瓣中分离出了NF-YC转录因子基因RhNF-YC9。RhNF-YC9表达在开花初期被诱导，但受到乙烯处理的抑制。沉默RhNF-YC9降低花瓣扩张的速度从阶段2到阶段5的参与细胞壁松动，细胞的膨胀调制，和细胞骨架重构11细胞扩张相关基因的表达均显著下调RhNF-YC9沉默的花瓣。我们还发现沉默RhNF-YC9降低赤霉素（GA）生物合成基因RhGA20ox的表达，同时显着增加GA分解代谢基因RhGA2ox的转录本，减少GA ₄和GA ₇的积累。乙烯处理对RhGA20ox和RhGA2ox表达的影响趋势相同。这些结果共同表明，RhNF-YC9积极调节花瓣的扩张速度，并介导乙烯和GA之间的串扰。我们的发现揭示了对参与乙烯调控的花瓣扩张的NF-YC转录因子功能的新见解。