Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
UT-ORNL Graduate School of Genome Science and Technology , University of Tennessee, Knoxville, TN 37996, USA.
Development. 2024 Jun 15;151(12). doi: 10.1242/dev.202870. Epub 2024 Jun 24.
The shoot apical meristem (SAM) gives rise to the aboveground organs of plants. The size of the SAM is relatively constant due to the balance between stem cell replenishment and cell recruitment into new organs. In angiosperms, the transcription factor WUSCHEL (WUS) promotes stem cell proliferation in the central zone of the SAM. WUS forms a negative feedback loop with a signaling pathway activated by CLAVATA3 (CLV3). In the periphery of the SAM, the ERECTA family receptors (ERfs) constrain WUS and CLV3 expression. Here, we show that four ligands of ERfs redundantly inhibit the expression of these two genes. Transcriptome analysis confirmed that WUS and CLV3 are the main targets of ERf signaling and uncovered new ones. Analysis of promoter reporters indicated that the WUS expression domain mostly overlaps with the CLV3 domain and does not shift along the apical-basal axis in clv3 mutants. Our three-dimensional mathematical model captured gene expression distributions at the single-cell level under various perturbed conditions. Based on our findings, CLV3 regulates cellular levels of WUS mostly through autocrine signaling, and ERfs regulate the spatial expression of WUS, preventing its encroachment into the peripheral zone.
茎尖分生组织（SAM）产生植物的地上器官。由于干细胞补充和细胞募集到新器官之间的平衡，SAM 的大小相对恒定。在被子植物中，转录因子 WUSCHEL（WUS）促进 SAM 中央区的干细胞增殖。WUS 与 CLAVATA3（CLV3）激活的信号通路形成负反馈回路。在 SAM 的外围，Erecta 家族受体（ERfs）限制 WUS 和 CLV3 的表达。在这里，我们表明 ERfs 的四个配体冗余地抑制这两个基因的表达。转录组分析证实 WUS 和 CLV3 是 ERf 信号的主要靶标，并揭示了新的靶标。启动子报告基因分析表明，WUS 的表达域与 CLV3 域大部分重叠，并且在 clv3 突变体中不会沿着顶端-基部轴移动。我们的三维数学模型在各种扰动条件下捕获了单细胞水平的基因表达分布。基于我们的发现，CLV3 主要通过自分泌信号调节 WUS 的细胞水平，而 ERfs 调节 WUS 的空间表达，防止其侵入外围区域。
