An Ze-Shan, Zuo Cun-Wu, Mao Juan, Ma Zong-Huan, Li Wen-Fang, Chen Bai-Hong
College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China.
Plants (Basel). 2024 Oct 18;13(20):2928. doi: 10.3390/plants13202928.
Bud-notching in pear varieties with weak-branches enhances branch development, hormone distribution, and germination, promoting healthier growth and improving early yield. To examine the regulatory mechanisms of endogenous hormones on lateral bud germination in spp. (cv. 'Huangguan') ( Rehd.), juvenile buds were collected from 2-year-old pear trees. Then, a comprehensive study, including assessments of endogenous hormones, germination and branching rates, RNA-seq analysis, and gene function analysis in these lateral buds was conducted. The results showed that there was no significant difference in germination rate between the control and bud-notching pear trees, but the long branch rate was significantly increased in bud-notching pear trees compared to the control ( < 0.05). After bud-notching, there was a remarkable increase in IAA and BR levels in the pruned section of shoots, specifically by 141% and 93%, respectively. However, the content of ABA in the lateral buds after bud-notching was not significantly different from the control. Based on RNA-seq analysis, a notable proportion of the differentially expressed genes (DEGs) were linked to the plant hormone signal transduction pathway. Notably, the brassinosteroid signaling pathway seemed to have the closest connection with the branching ability of pear with the related genes encoding and , which showed significant differences between lateral buds. Finally, the heterologous expression of has a positive regulatory effect on the increased growth and branching numbers. Therefore, the was identified as an up-regulated gene that is induced via brassinosteroid (BR) and could act as a conduit, transforming bud-notching cues into proliferative signals, thereby governing lateral branching mechanisms in pear trees.
对弱枝梨品种进行芽刻伤可促进枝条发育、激素分布和萌发，促进更健康的生长并提高早期产量。为了研究内源激素对梨属植物（品种‘皇冠’）侧芽萌发的调控机制，从2年生梨树中采集幼芽。然后，对这些侧芽进行了一项综合研究，包括内源激素评估、萌发和分枝率评估、RNA测序分析以及基因功能分析。结果表明，对照梨树和芽刻伤梨树的萌发率没有显著差异，但芽刻伤梨树的长枝率与对照相比显著增加（P<0.05）。芽刻伤后，新梢修剪部位的生长素（IAA）和油菜素内酯（BR）水平显著增加，分别增加了141%和93%。然而，芽刻伤后侧芽中脱落酸（ABA）的含量与对照没有显著差异。基于RNA测序分析，相当一部分差异表达基因（DEGs）与植物激素信号转导途径有关。值得注意的是，油菜素内酯信号通路似乎与梨的分枝能力关系最为密切，相关基因编码[具体基因名称未给出]，在侧芽之间表现出显著差异。最后，[具体基因名称未给出]的异源表达对[具体植物名称未明确写出]的生长增加和分枝数具有正向调控作用。因此，[具体基因名称未给出]被鉴定为一个通过油菜素内酯（BR）诱导上调的基因，它可以作为一个传导途径，将芽刻伤信号转化为增殖信号，从而调控梨树的侧枝分枝机制。
