Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture, College of Horticulture, China Agricultural University, Beijing, 100193, China.
J Exp Bot. 2023 Aug 17;74(15):4489-4502. doi: 10.1093/jxb/erad173.
In cut rose (Rosa hybrida), the flower-opening process is closely associated with vase life. Auxin induces the expression of transcription factor genes that function in petal growth via cell expansion. However, the molecular mechanisms underlying the auxin effect during flower opening are not well understood. Here, we identified the auxin-inducible transcription factor gene RhMYB6, whose expression level is high during the early stages of flower opening. Silencing of RhMYB6 delayed flower opening by controlling petal cell expansion through down-regulation of cell expansion-related genes. Furthermore, we demonstrated that the auxin response factor RhARF2 directly interacts with the promoter of RhMYB6 and represses its transcription. Silencing of RhARF2 resulted in larger petal size and delayed petal movement. We also showed that the expression of genes related to ethylene and petal movement showed substantial differences in RhARF2-silenced petals. Our results indicate that auxin-regulated RhARF2 is a critical player that controls flower opening by governing RhMYB6 expression and mediating the crosstalk between auxin and ethylene signaling.
在切花月季（Rosa hybrida）中，开花过程与瓶插寿命密切相关。生长素通过细胞扩展诱导在花瓣生长中起作用的转录因子基因的表达。然而，生长素在开花过程中的作用的分子机制尚不清楚。在这里，我们鉴定了生长素诱导的转录因子基因 RhMYB6，其在开花早期的表达水平较高。通过下调与细胞扩展相关的基因来控制花瓣细胞扩展，RhMYB6 的沉默会延迟开花。此外，我们证明生长素反应因子 RhARF2 直接与 RhMYB6 的启动子相互作用并抑制其转录。RhARF2 的沉默导致花瓣尺寸更大且花瓣运动延迟。我们还表明，与乙烯和花瓣运动相关的基因的表达在 RhARF2 沉默的花瓣中存在显著差异。我们的结果表明，生长素调节的 RhARF2 通过调节 RhMYB6 的表达和介导生长素和乙烯信号之间的串扰来控制开花，是一个关键的调控因子。
