Evolution of buffering in a genetic circuit controlling plant stem cell proliferation

First author: Daniel Rodriguez-Leal; Affiliations: Cold Spring Harbor Laboratory (冷泉港实验室): NY, USA

Corresponding author: Zachary B. Lippman

Precise control of plant stem cell proliferation is necessary for the continuous and reproducible development of plant organs. The peptide ligand CLAVATA3 (CLV3) and its receptor protein kinase CLAVATA1 (CLV1) maintain stem cell homeostasis within a deeply conserved negative feedback circuit. In Arabidopsis, CLV1 paralogs also contribute to homeostasis, by compensating for the loss of CLV1 through transcriptional upregulation. Here, we show that compensation operates in diverse lineages for both ligands and receptors, but while the core CLV signaling module is conserved, compensation mechanisms have diversified. Transcriptional compensation between ligand paralogs operates in tomato, facilitated by an ancient gene duplication that impacted the domestication of fruit size. In contrast, we found little evidence for transcriptional compensation between ligands in Arabidopsis and maize, and receptor compensation differs between tomato and Arabidopsis. Our findings show that compensation among ligand and receptor paralogs is critical for stem cell homeostasis, but that diverse genetic mechanisms buffer conserved developmental programs.

植物干细胞增殖具有非常精细的调控机制，这对于植物器官连续并且可再生发育是非常重要的。多肽配基CLV3以及其受体蛋白激酶CLV1以一个非常保守的负反馈循环维持干细胞的内稳态。在拟南芥中，CLV1基因的旁系同源基因能够在CLV1基因功能缺失时转录上调，作为一种补偿机制来替代CLV1作用于干细胞的内稳态。本文，作者的研究显示在不同的植物谱系中对于配基和受体都存在补偿机制，虽然核心的CLV信号模块在不同物种间会比较保守，但补偿机制却很多样化。配基同源物的转录补偿在西红柿中存在，由一个古老的基因复制产物所促进，该基因还作用于西红柿驯化过程中的果实大小。相反，作者并未发现拟南芥和玉米中存在配基间的转录补偿，并且受体补偿在西红柿和拟南芥中存在差异。本文的研究结果显示配基和受体同源物的补偿机制对于干细胞内稳态的位置至关重要，但多样化的遗传机制保护了这种保守的发育进程。

通讯：Zachary Lippman  (https://www.cshl.edu/research/faculty-staff/zachary-lippman/#news)

研究方向：决定植物何时、何处开花以及花数量的调控因子。

doi: https://doi.org/10.1038/s41588-019-0389-8

Journal: Nature Genetics

Published date: April 15, 2019