Bud endodormancy in perennial plants is a sophisticated system that adapts to seasonal climatic changes. Growth-promoting signals such as low temperature and gibberellins (GAs) are crucial for facilitating budbreak following endodormancy release (EDR). However, the regulatory mechanisms underlying GA-mediated budbreak in tree peony (Paeonia suffruticosa) remain unclear. In tree peony, the expression of PsmiR159b among three differentially expressed miR159 members was inhibited with the prolonged chilling, and overexpression of PsMIR159b delayed budbreak, whereas silencing PsmiR159b promoted budbreak after dormancy. PsMYB65, a downstream transcription factor in the GA pathway, was induced by prolonged chilling and exogenous GA3 treatments. PsMYB65 was identified as a target of PsmiR159b, and promoted budbreak in tree peony. RNA-seq of PsMYB65-slienced buds revealed significant enrichment in the GO terms regulation of “cell cycle” and “DNA replication” among differentially expressed genes. Yeast one-hybrid and electrophoretic mobility shift assays demonstrated that PsMYB65 directly bound to the promoter of the type-D cyclin gene PsCYCD3;1. Dual-luciferase reporter assay indicated that PsMYB65 positively regulate PsCYCD3;1 expression, suggesting that miR159b-PsMYB65 module contributes to budbreak by influencing the cell cycle. Our findings revealed that the PsmiR159b-PsMYB65 module functioned in budbreak after dormancy by regulating cell proliferation, providing valuable insights into the endodormancy release regulation mechanism.

中文翻译：

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PsmiR159b-PsMYB65 模块通过影响牡丹的细胞周期来恢复休眠后的芽生长

多年生植物的芽休眠是一个适应季节性气候变化的复杂系统。低温和赤霉素 (GA) 等促生长信号对于促进内休眠释放 (EDR) 后的发芽至关重要。然而，GA 介导的牡丹 (Paeonia suffruticosa) 发芽的调控机制仍不清楚。在牡丹中，三个差异表达的miR159成员中PsmiR159b的表达随着长时间的低温而受到抑制，并且PsMIR159b的过表达延迟了发芽，而沉默PsmiR159b促进了休眠后的发芽。PsMYB65 是 GA 途径中的下游转录因子，由长期低温和外源 GA3 处理诱导。PsMYB65 被确定为 PsmiR159b 的靶标，可促进牡丹的发芽。PsMYB65 沉默芽的 RNA-seq 显示差异表达基因中“细胞周期”和“DNA 复制”的 GO 术语调控显着富集。酵母单杂交和电泳迁移率变动分析表明，PsMYB65 直接结合至 D 型细胞周期蛋白基因 PsCYCD3 的启动子；1。双荧光素酶报告基因检测表明，PsMYB65 正向调节 PsCYCD3;1 的表达，表明 miR159b-PsMYB65 模块通过影响细胞周期来促进发芽。我们的研究结果表明，PsmiR159b-PsMYB65 模块在休眠后的发芽过程中通过调节细胞增殖发挥作用，为了解休眠释放调节机制提供了有价值的见解。