不定根(AR)的形成是苹果砧木大量繁殖的瓶颈,和水的压力严重限制了它。苹果无性系中不同的激素和糖信号通路决定了水分胁迫下AR的形成,但是这些并不完全理解。为了识别它们,GL-3茎插条在聚乙二醇(PEG)处理上培养。通过增加脱落酸(ABA)的内源含量,与无PEG对照(CK)插条相比,AR的形成显着降低。玉米素核苷(ZR),和茉莉酸甲酯(JA-me),并降低吲哚-3-乙酸(IAA)和赤霉酸3(GA3)的含量。我们进行了转录组学分析以鉴定表型背后的反应。在CK和PEG之间共鉴定出3204个差异表达基因(DEGs),1702个上调基因和1502个下调基因。调查显示,大约312个DEGs强烈富含激素信号,糖代谢,根系发育,和细胞周期相关途径。因此,他们因可能参与不定根而被选中。然而,ABA的积累越多,ZR,和JA-me含量及其相关基因的上调,以及糖代谢相关基因的下调,导致ARs的抑制。这些结果表明,AR的形成是一个复杂的生物学过程,主要受多种激素信号通路和糖代谢的影响。这是第一个证明PEG如何抑制苹果植物中AR形成的研究。
Adventitious root (AR) formation is a bottleneck for the mass propagation of apple rootstocks, and water stress severely restricts it. Different hormones and sugar signaling pathways in apple clones determine AR formation under water stress, but these are not entirely understood. To identify them, GL-3 stem cuttings were cultured on polyethylene glycol (PEG) treatment. The AR formation was dramatically decreased compared with the PEG-free control (CK) cuttings by increasing the endogenous contents of abscisic acid (ABA), zeatin riboside (ZR), and methyl jasmonate (JA-me) and reducing the indole-3-acetic acid (IAA) and gibberellic acid 3 (GA3) contents. We performed a transcriptomic analysis to identify the responses behind the phenotype. A total of 3204 differentially expressed genes (DEGs) were identified between CK and PEG, with 1702 upregulated and 1502 downregulated genes. Investigation revealed that approximately 312 DEGs were strongly enriched in hormone signaling, sugar metabolism, root development, and cell cycle-related pathways. Thus, they were selected for their possible involvement in adventitious rooting. However, the higher accumulation of ABA, ZR, and JA-me contents and the upregulation of their related genes, as well as the downregulation of sugar metabolism-related genes, lead to the inhibition of ARs. These results indicate that AR formation is a complicated biological process chiefly influenced by multiple hormonal signaling pathways and sugar metabolism. This is the first study to demonstrate how PEG inhibits AR formation in apple plants.