Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University, Beijing, 100083, China.
College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China.
New Phytol. 2023 Jan;237(1):192-203. doi: 10.1111/nph.18508. Epub 2022 Oct 17.
Bud dormancy is essential for perennial trees that survive the cold winters and to flower on time in the following spring. Histone modifications have been reported to be involved in the control of the dormancy cycle and DAM/SVPs are considered targets. However, how the histone modification marks are added to the specific gene loci during bud dormancy cycle is still unknown. Using yeast-two hybrid library screening and co-immunoprecipitation assays, we found that PpyABF3, a key protein regulating bud dormancy, recruits Complex of Proteins Associated with Set1-like complex via interacting with PpyWDR5a, which increases the H3K4me3 deposition at DAM4 locus. Chromatin immunoprecipitation-quantitative polymerase chain reaction showed that PpyGA2OX1 was downstream gene of PpyABF3 and it was also activated by H3K4me3 deposition. Silencing of GA2OX1 in pear calli and pear buds resulted in a similar phenotype with silencing of ABF3. Furthermore, overexpression of PpyWDR5a increased H3K4me3 levels at DAM4 and GA2OX1 loci and inhibited the growth of pear calli, whereas silencing of PpyWDR5a in pear buds resulted in a higher bud-break percentage. Our findings provide new insights into how H3K4me3 marks are added to dormancy-related genes in perennial woody plants and reveal a novel mechanism by which ABF3 integrates abscisic acid signaling and gibberellic acid catabolism during bud dormancy maintenance.
芽休眠对于能在寒冷的冬季存活并在下一个春天按时开花的多年生树木至关重要。据报道,组蛋白修饰参与了休眠周期的调控,DAM/SVPs 被认为是其靶标。然而,在芽休眠周期中,组蛋白修饰标记是如何添加到特定的基因座的,目前尚不清楚。通过酵母双杂交文库筛选和共免疫沉淀实验,我们发现,调控芽休眠的关键蛋白 PpyABF3 通过与 PpyWDR5a 相互作用招募与 Set1 样复合物相关的蛋白复合物,从而增加 DAM4 基因座处的 H3K4me3 沉积。染色质免疫沉淀-定量聚合酶链反应显示,PpyGA2OX1 是 PpyABF3 的下游基因,其也受 H3K4me3 沉积的激活。在梨愈伤组织和梨芽中沉默 GA2OX1 导致与沉默 ABF3 相似的表型。此外,过表达 PpyWDR5a 增加了 DAM4 和 GA2OX1 基因座处的 H3K4me3 水平,并抑制了梨愈伤组织的生长,而在梨芽中沉默 PpyWDR5a 则导致更高的芽破眠率。我们的研究结果为组蛋白修饰标记如何添加到多年生木本植物休眠相关基因提供了新的见解,并揭示了 ABF3 在芽休眠维持过程中整合脱落酸信号和赤霉素代谢的新机制。