College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, China.
State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong, China.
J Exp Bot. 2020 Jun 22;71(12):3512-3523. doi: 10.1093/jxb/eraa119.
In a previous study we identified EARLY BUD BREAK 1 (EBB1), an ERF transcription factor, in peach (Prunus persica var. nectarina cultivar Zhongyou 4); however, little is known of how PpEBB1 may regulate bud break. To verify the function of PpEBB1 in bud break, PpEBB1 was transiently transformed into peach buds, resulting in early bud break. Bud break occurred earlier in PpEBB1-oe poplar (Populus trichocarpa) obtained by heterologous transformation than in wild type (WT), consistent with the peach bud results, indicating that PpEBB1 can promote bud break. To explore how PpEBB1 affects bud break, differentially expressed genes (DEGs) between WT and PpEBB1-oe poplar plants were identified by RNA-sequencing. The expression of DEGs associated with hormone metabolism, cell cycle, and cell wall modifications changed substantially according to qRT-PCR. Auxin, ABA, and total trans-zeatin-type cytokinin levels were higher in the PpEBB1-oe plants than in WT plants, while the total N6-(Δ 2-isopentenyl)-adenine-type cytokinins was lower. Yeast two-hybrid and bimolecular fluorescence complementation assays verified that a cell wall modification-related protein (PpEXBL1) interacted with PpEBB1 suggesting that PpEBB1 could interact with these cell wall modification proteins directly. Overall, our study proposed a multifaceted explanation for how PpEBB1 regulates bud break and showed that PpEBB1 promotes bud break by regulating hormone metabolism, the cell cycle, and cell wall modifications.
在之前的研究中，我们在桃（Prunus persica var. nectarina 栽培品种 Zhongyou 4）中鉴定了 EARLY BUD BREAK 1（EBB1），一种 ERF 转录因子；然而，关于 PpEBB1 如何调节芽休眠的信息知之甚少。为了验证 PpEBB1 在芽休眠中的功能，我们将 PpEBB1 瞬时转化到桃芽中，导致芽提前休眠。通过异源转化获得的 PpEBB1-oe 杨树（Populus trichocarpa）比野生型（WT）的芽休眠提前，与桃芽的结果一致，表明 PpEBB1 可以促进芽休眠。为了探索 PpEBB1 如何影响芽休眠，我们通过 RNA-seq 鉴定了 WT 和 PpEBB1-oe 杨树之间差异表达的基因（DEGs）。根据 qRT-PCR，与激素代谢、细胞周期和细胞壁修饰相关的 DEGs 的表达发生了显著变化。PpEBB1-oe 植物中的生长素、ABA 和总 trans-玉米素型细胞分裂素水平高于 WT 植物，而总 N6-（Δ 2-异戊烯基）-腺嘌呤型细胞分裂素水平较低。酵母双杂交和双分子荧光互补测定验证了细胞壁修饰相关蛋白（PpEXBL1）与 PpEBB1 相互作用，表明 PpEBB1 可以直接与这些细胞壁修饰蛋白相互作用。总体而言，我们的研究提出了 PpEBB1 调节芽休眠的多方面解释，并表明 PpEBB1 通过调节激素代谢、细胞周期和细胞壁修饰来促进芽休眠。
