Axillary meristems (AMs) give rise to lateral shoots and are critical to plant architecture. Understanding how developmental cues and environmental signals impact AM development will enable the improvement of plant architecture in agriculture. Here, we show that ARGONAUTE10 (AGO10), which sequesters miR165/166, promotes AM development through the miR165/166 target gene REVOLUTA. We reveal that AGO10 expression is precisely controlled temporally and spatially by auxin, brassinosteroids, and light to result in AM initiation only in the axils of leaves at a certain age. AUXIN RESPONSE FACTOR 5 (ARF5) activates while BRASSINAZOLE-RESISTANT 1 (BZR1) and PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) repress AGO10 transcription directly. In axils of young leaves, BZR1 and PIF4 repress AGO10 expression to prevent AM initiation. In axils of older leaves, ARF5 upregulates AGO10 expression to promote AM initiation. Our results uncover the spatiotemporal control of AM development through the cooperation of hormones and light converging on a regulator of microRNA.

腋生分生组织 (AMs) 产生侧枝，对植物结构至关重要。了解发育线索和环境信号如何影响 AM 发育将有助于改善农业植物结构。在这里，我们展示了隔离 miR165/166 的 ARGONAUTE10 (AGO10) 通过 miR165/166 靶基因REVOLUTA促进 AM 发育。我们发现AGO10表达在时间和空间上受到生长素、油菜素类固醇和光的精确控制，导致 AM 仅在特定年龄的叶腋中启动。AUXIN RESPONSE Factor 5 ( ARF5 ) 激活而BRASSINAZOLE-RESISTANT 1 ( BZR1 ) 和光敏色素相互作用因子 4 ( PIF4 )直接抑制AGO10转录。在年轻的叶腋，BZR1和PIF4再加压AGO10表达，防止AM开始。在老叶的腋下，ARF5上调AGO10表达以促进 AM 启动。我们的研究结果揭示了通过激素和光在 microRNA 调节器上的协同作用对 AM 发展的时空控制。