PDF(Pubmed)
Abstract：
BACKGROUND: Flower load in peach is an important determinant of final fruit quality and is subjected to cost-effective agronomical practices, such as the thinning, to finely balance the sink-source relationships within the tree and drive the optimal amount of assimilates to the fruits. Floral transition in peach buds occurs as a result of the integration of specific environmental signals, such as light and temperature, into the endogenous pathways that induce the meristem to pass from vegetative to reproductive growth. The cross talk and integration of the different players, such as the genes and the hormones, are still partially unknown. In the present research, transcriptomics and hormone profiling were applied on bud samples at different developmental stages. A gibberellin treatment was used as a tool to identify the different phases of floral transition and characterize the bud sensitivity to gibberellins in terms of inhibition of floral transition.
RESULTS: Treatments with gibberellins showed different efficacies and pointed out a timeframe of maximum inhibition of floral transition in peach buds. Contextually, APETALA1 gene expression was shown to be a reliable marker of gibberellin efficacy in controlling this process. RNA-Seq transcriptomic analyses allowed to identify specific genes dealing with ROS, cell cycle, T6P, floral induction control and other processes, which are correlated with the bud sensitivity to gibberellins and possibly involved in bud development during its transition to the reproductive stage. Transcriptomic data integrated with the quantification of the main bioactive hormones in the bud allowed to identify the main hormonal regulators of floral transition in peach, with a pivotal role played by endogenous gibberellins and cytokinins.
CONCLUSIONS: The peach bud undergoes different levels of receptivity to gibberellin inhibition. The stage with maximum responsiveness corresponded to a transcriptional and hormonal crossroad, involving both flowering inhibitors and inductors. Endogenous gibberellin levels increased only at the latest developmental stage, when floral transition was already partially achieved, and the bud was less sensitive to exogenous treatments. A physiological model summarizes the main findings and suggests new research ideas to improve our knowledge about floral transition in peach.
RESULTS: Treatments with gibberellins showed different efficacies and pointed out a timeframe of maximum inhibition of floral transition in peach buds. Contextually, APETALA1 gene expression was shown to be a reliable marker of gibberellin efficacy in controlling this process. RNA-Seq transcriptomic analyses allowed to identify specific genes dealing with ROS, cell cycle, T6P, floral induction control and other processes, which are correlated with the bud sensitivity to gibberellins and possibly involved in bud development during its transition to the reproductive stage. Transcriptomic data integrated with the quantification of the main bioactive hormones in the bud allowed to identify the main hormonal regulators of floral transition in peach, with a pivotal role played by endogenous gibberellins and cytokinins.
CONCLUSIONS: The peach bud undergoes different levels of receptivity to gibberellin inhibition. The stage with maximum responsiveness corresponded to a transcriptional and hormonal crossroad, involving both flowering inhibitors and inductors. Endogenous gibberellin levels increased only at the latest developmental stage, when floral transition was already partially achieved, and the bud was less sensitive to exogenous treatments. A physiological model summarizes the main findings and suggests new research ideas to improve our knowledge about floral transition in peach.
摘要：
背景：桃中的花负荷是最终果实质量的重要决定因素，并且受到具有成本效益的农艺实践的影响，比如变薄，精细平衡树内的汇-源关系，并驱动最佳量的同化物的果实。桃芽中的花转变是由于特定环境信号的整合而发生的，比如光和温度，进入诱导分生组织从营养生长到生殖生长的内源性途径。不同玩家的串扰和融合，比如基因和荷尔蒙，仍然部分未知。在目前的研究中,转录组学和激素谱分析应用于不同发育阶段的芽样品。赤霉素处理被用作识别花转变的不同阶段的工具，并在抑制花转变方面表征芽对赤霉素的敏感性。
结果：用赤霉素处理显示出不同的功效，并指出了最大抑制桃芽中花过渡的时间范围。上下文中,APETALA1基因表达被证明是控制该过程的赤霉素功效的可靠标记。RNA-Seq转录组学分析允许鉴定处理ROS的特定基因，细胞周期,T6P,花卉诱导控制和其他过程，这与芽对赤霉素的敏感性相关，并且可能在其向生殖阶段过渡期间参与芽的发育。转录组数据与芽中主要生物活性激素的定量相结合，可以确定桃花过渡的主要激素调节剂，内源性赤霉素和细胞分裂素起关键作用。
结论：桃芽经历不同程度的赤霉素抑制的接受性。具有最大反应性的阶段对应于转录和激素的十字路口，涉及开花抑制剂和诱导剂。内源性赤霉素水平仅在最新的发育阶段增加，当花卉过渡已经部分实现时，芽对外源处理不太敏感。生理模型总结了主要发现，并提出了新的研究思路，以提高我们对桃花过渡的认识。
结果：用赤霉素处理显示出不同的功效，并指出了最大抑制桃芽中花过渡的时间范围。上下文中,APETALA1基因表达被证明是控制该过程的赤霉素功效的可靠标记。RNA-Seq转录组学分析允许鉴定处理ROS的特定基因，细胞周期,T6P,花卉诱导控制和其他过程，这与芽对赤霉素的敏感性相关，并且可能在其向生殖阶段过渡期间参与芽的发育。转录组数据与芽中主要生物活性激素的定量相结合，可以确定桃花过渡的主要激素调节剂，内源性赤霉素和细胞分裂素起关键作用。
结论：桃芽经历不同程度的赤霉素抑制的接受性。具有最大反应性的阶段对应于转录和激素的十字路口，涉及开花抑制剂和诱导剂。内源性赤霉素水平仅在最新的发育阶段增加，当花卉过渡已经部分实现时，芽对外源处理不太敏感。生理模型总结了主要发现，并提出了新的研究思路，以提高我们对桃花过渡的认识。
