Unlike annual flowering plants that exhibit a single reproductive cycle encompassing vegetative growth, flowering, and senescence within a single year, perennial woody trees undergo a transition between vegetative and reproductive growth every year after a long juvenile phase. Most woody fruit trees bloom when it turns warm in spring, and the fruit ripens in summer or autumn. However, as a member of the Maloideae subfamily, the loquat tree blooms in the cold autumn and winter, and the fruit matures in the spring. To explore the regulatory mechanism of loquat flowering, we characterized two homologous genes in loquat, and . qRT-PCR results revealed that and exhibited nearly opposite expression patterns in various tissues. was mainly expressed in young tissues; was mainly expressed in mature leaves, open flowers, and fruits. exhibited an obvious circadian rhythm and was regulated by EjCO. After the trees were exposed to short-day conditions or sprayed with exogenous GA, the expression of was strongly inhibited, and the loquat tree did not produce floral buds. Furthermore, the yeast two-hybrid, bimolecular fluorescence complementation, and Dual-luciferase assay experiments revealed that both EjFT1 and EjFT2 interacted with EjFD, with the EjFT2-EjFD protein complex enhancing the activity of EjAP1-1 and promoters, while EjFT1-EjFD inhibited the activity of the promoter. Protein structural analysis of EjFT1 and EjFT2 suggested that differences in amino acid residues at Val/Leu, Ser/Ala, and Val/Ala may be the reason for their functional differences. Our results showed that EjFT1 and EjFT2 may cooperatively regulate the floral bud differentiation of loquat by competitively binding with EjFD. regulates the onset of loquat floral bud differentiation by responding to photoperiod and gibberellin signals, while is involved in the vegetative growth of loquat. These findings provide important clues for the investigation of the regulatory mechanism of loquat flowering and advance the exploration into the multiple roles of homologous genes in regulating the reproductive transformation and vegetative growth of flowering plants.

中文翻译：

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两个FT基因协同调控枇杷生殖转变


与一年生开花植物在一年内表现出单一生殖周期（包括营养生长、开花和衰老）不同，多年生木本树木在漫长的幼年期后，每年都会经历营养生长和生殖生长之间的过渡。大多数木本果树在春季温暖时开花，在夏季或秋季果实成熟。然而，作为枇杷亚科的一员，枇杷树在寒冷的秋冬开花，在春季果实成熟。为了探索枇杷开花的调控机制，我们对枇杷中的两个同源基因进行了表征。 qRT-PCR 结果显示 和 在不同组织中表现出几乎相反的表达模式。主要在年轻组织中表达；主要表现在成熟的叶子、开放的花朵和果实中。表现出明显的昼夜节律并受到EjCO的调节。树木暴露于短日照条件或喷施外源GA后， 的表达受到强烈抑制，枇杷树不产生花芽。此外，酵母双杂交、双分子荧光互补和双荧光素酶测定实验表明，EjFT1和EjFT2均与EjFD相互作用，EjFT2-EjFD蛋白复合物增强EjAP1-1和启动子的活性，而EjFT1-EjFD抑制EjAP1-1和启动子的活性。启动子的活性。 EjFT1和EjFT2的蛋白质结构分析表明Val/Leu、Ser/Ala和Val/Ala氨基酸残基的差异可能是其功能差异的原因。结果表明，EjFT1和EjFT2可能通过与EjFD竞争性结合来协同调控枇杷花芽分化。 通过响应光周期和赤霉素信号调节枇杷花芽分化的开始，同时参与枇杷的营养生长。这些发现为枇杷开花调控机制的研究提供了重要线索，推进了同源基因在调控开花植物生殖转化和营养生长中多重作用的探索。