The control of cell-cell communication via plasmodesmata (PD) plays a key role in plant development. In tree buds, low-temperature conditions (LT) induce a switch in plasmodesmata from a closed to an open state, which restores cell-to-cell communication in the shoot apex and releases dormancy. Using genetic and cell-biological approaches, we have identified a previously uncharacterized transcription factor, Low-temperature-Induced MADS-box 1 (LIM1), as an LT-induced, direct upstream activator of the gibberellic acid (GA) pathway. The LIM1-GA module mediates low temperature-induced plasmodesmata opening, by negatively regulating callose accumulation to promote dormancy release. LIM1 also activates expression of FT1 (FLOWERING LOCUS T), another LT-induced factor, with LIM1-FT1 forming a coherent feedforward loop converging on low-temperature regulation of gibberellin signaling in dormancy release. Mathematical modeling and experimental validation suggest that negative feedback regulation of LIM1 by gibberellin could play a crucial role in maintaining the robust temporal regulation of bud responses to low temperature. These results reveal genetic factors linking temperature control of cell-cell communication with regulation of seasonally-aligned growth crucial for adaptation of trees.

中文翻译：

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介导细胞间通讯温度控制的调节模块促进了树芽休眠的释放。


通过胞间连丝 （PD） 控制细胞间通讯在植物发育中起着关键作用。在树芽中，低温条件 （LT） 诱导胞间连丝从关闭状态切换到开放状态，从而恢复芽顶端的细胞间通讯并释放休眠。使用遗传和细胞生物学方法，我们已经确定了一种以前未表征的转录因子，低温诱导的 MADS-box 1 （LIM1），作为赤霉酸 （GA） 通路的 LT 诱导的直接上游激活剂。LIM1-GA 模块通过负向调节胼胝质积累以促进休眠释放，介导低温诱导的胞间连丝打开。LIM1 还激活另一种 LT 诱导因子 FT1 （FLOWERING LOCUS T） 的表达，LIM1-FT1 形成一个连贯的前馈环，在休眠释放中赤霉素信号的低温调节上收敛。数学建模和实验验证表明，赤霉素对 LIM1 的负反馈调节可能在维持芽对低温反应的稳健时间调节中发挥关键作用。这些结果揭示了将细胞间通讯的温度控制与季节性对齐生长调节联系起来的遗传因素，这对树木的适应至关重要。