Gao Feng, Segbo Silas, Huang Xiao, Zhou Pengyu, Ma Chengdong, Ma Yufan, Lin Ximeng, Bai Yang, Tan Wei, Coulibaly Daouda, Ouma Kenneth Omondi, Iqbal Shahid, Ni Zhaojun, Shi Ting, Gao Zhihong
Laboratory of Fruit Tree Biotechnology, College of Horticulture, Nanjing Agricultural University, Nanjing, China.
Laboratory of Forestry Research, Xing'an League Institute of Forestry, Ulanhot, China.
Plant Cell Environ. 2025 May;48(5):3415-3430. doi: 10.1111/pce.15356. Epub 2025 Jan 5.
Temperate fruit trees rely on environmental and endogenous signals to trigger dormancy release and flowering. However, the knowledge of DELLA protein PmRGL2, a Prunus mume homolog of REPRESSOR OF GA-Like 2 (RGL2), which serves as an important inhibitory factor in gibberellin (gibberellin acid [GA]) signalling, is limited related to on its regulatory effects on dormancy release and flowering. In our study, the protein-protein interaction assays showed an interaction between PmRGL2 and PmFRL3, a Prunus mume homolog of FRIGIDA-LIKE (FRL). The FRL protein regulates flowering induction by binding to chaperone proteins. To understand the transcriptional regulation of PmRGL2 in Prunus mume, in detail's we constructed a ChIP-Seq library at four key stages of flower bud development. Genome-wide analysis screened a MCM1-AGAMOUSDEFICIENS Serum Response Factor box (MADS box) protein for two SHORT VEGETATIVE PHASEs (SVPs). Genetic analysis showed that overexpressing PmSVP in Arabidopsis thaliana reduced the GA content and delayed flowering, whereas PmSVP-like overexpression increased the GA content and promoted flowering. Protein-DNA binding assays revealed that the PmRGL2/PmFRL3 protein complex promoted PmSVP transcription while repressing PmSVP-like transcription, which inhibited the flowering process. As chilling requirements increased, the PmFRL3 protein was degraded. ThePmRGL2/PmFRL3 protein complex is disrupted. With the increase in the GA content within the flower buds, the PmRGL2 protein was degraded in response to GA signalling, and the function of PmSVP-like was released. It dominated flowering, leading to this process in Prunus mume. Therefore, we propose a mechanism by which the PmRGL2/PmFRL3 protein complex responds to GA and low-temperature signalling to regulate PmSVP and PmSVP-like synergistically and thus Prunus mume flowering time.
温带果树依靠环境和内源信号来触发休眠解除和开花。然而，关于DELLA蛋白PmRGL2（一种梅花中与赤霉素信号抑制因子（RGL2）同源的蛋白），其作为赤霉素（赤霉酸[GA]）信号传导中的重要抑制因子，对休眠解除和开花的调控作用的了解有限。在我们的研究中，蛋白质 - 蛋白质相互作用分析表明PmRGL2与梅花中与FRIGIDA样（FRL）同源的PmFRL3之间存在相互作用。FRL蛋白通过与伴侣蛋白结合来调节开花诱导。为了详细了解PmRGL2在梅花中的转录调控，我们在花芽发育的四个关键阶段构建了ChIP-Seq文库。全基因组分析筛选出了两个SHORT VEGETATIVE PHASEs（SVPs）的MCM1-AGAMOUSDEFICIENS血清反应因子盒（MADS盒）蛋白。遗传分析表明，在拟南芥中过表达PmSVP会降低GA含量并延迟开花，而过表达PmSVP样蛋白则会增加GA含量并促进开花。蛋白质 - DNA结合分析表明，PmRGL2/PmFRL3蛋白复合物促进PmSVP转录，同时抑制PmSVP样转录，从而抑制开花过程。随着需冷量增加，PmFRL3蛋白被降解。PmRGL2/PmFRL3蛋白复合物被破坏。随着花芽内GA含量的增加，PmRGL2蛋白响应GA信号而被降解，PmSVP样蛋白的功能被释放。它主导开花，导致梅花的这一过程。因此，我们提出了一种机制，即PmRGL2/PmFRL3蛋白复合物响应GA和低温信号，协同调节PmSVP和PmSVP样蛋白，从而调控梅花的开花时间。
