Plants have a high ability to cope with changing environments and grow continuously throughout life. However, the mechanisms by which plants strike a balance between stress response and organ growth remain elusive. Here, we found that DNA double-strand breaks enhance the accumulation of cytokinin hormones through the DNA damage signaling pathway in the Arabidopsis root tip. Our data showed that activation of cytokinin signaling suppresses the expression of some of the PIN-FORMED genes that encode efflux carriers of another hormone, auxin, thereby decreasing the auxin signals in the root tip and causing cell cycle arrest at G₂ phase and stem cell death. Elevated cytokinin signaling also promotes an early transition from cell division to endoreplication in the basal part of the root apex. We propose that plant hormones spatially coordinate differential DNA damage responses, thereby maintaining genome integrity and minimizing cell death to ensure continuous root growth.

植物有很强的能力来应对不断变化的环境，并在整个生命中不断地生长。然而，植物在应激反应和器官生长之间取得平衡的机制仍然难以捉摸。在这里，我们发现 DNA 双链断裂通过拟南芥根尖中的 DNA 损伤信号通路增强了细胞分裂素激素的积累。我们的数据表明，细胞分裂素信号的激活抑制了一些PIN 形成的基因的表达，这些基因编码另一种激素的外排载体，生长素，从而降低根尖中的生长素信号并导致细胞周期停滞在 G ₂期和干细胞死亡。升高的细胞分裂素信号传导也促进了根尖基部从细胞分裂到核内复制的早期转变。我们建议植物激素在空间上协调不同的 DNA 损伤反应，从而保持基因组完整性并最大限度地减少细胞死亡，以确保持续的根系生长。