Auxin Response Factors promote organogenesis by chromatin-mediated repression of the pluripotency gene SHOOTMERISTEMLESS

First author: Yuhee Chung; Affiliations: University of Pennsylvania (宾夕法尼亚大学): Philadelphia, USA

Corresponding author: Doris Wagner 

Specification of new organs from transit amplifying cells is critical for higher eukaryote development. In plants, a central stem cell pool maintained by the pluripotency factor SHOOTMERISTEMLESS (STM), is surrounded by transit amplifying cells competent to respond to auxin hormone maxima by giving rise to new organs. Auxin triggers flower initiation through Auxin Response Factor (ARF) MONOPTEROS (MP) and recruitment of chromatin remodelers to activate genes promoting floral fate. The contribution of gene repression to reproductive primordium initiation is poorly understood. Here we show that downregulation of the STM pluripotency gene promotes initiation of flowers and uncover the mechanism for STM silencing. The ARFs ETTIN (ETT) and ARF4 promote organogenesis at the reproductive shoot apex in parallel with MP via histone-deacetylation mediated transcriptional silencing of STM. ETT and ARF4 directly repress STM, while MP acts indirectly, through its target FILAMENTOUS FLOWER (FIL). Our data suggest that – as in animals- downregulation of the pluripotency program is important for organogenesis in plants.

从过渡-扩增细胞到新器官的特化对于高等真核生物的发育至关重要。在植物中，由STM所维持的植物中心干细胞池被过渡-扩增细胞所包裹以响应生长素极点，进而产生新的器官。生长素通过生长素响应因子MP和染色质重塑因子的招募以激活那些能够促进成花命运相关基因的表达，从而诱导成花起始。目前有关基因抑制对于生殖原基起始的作用还不清楚。本文研究显示STM基因的下调促进成花起始，并且揭示了STM沉默的分子机制。生长素响应因子ETT和ARF4与MP平行作用，通过组蛋白去乙酰化介导的STM转录沉默促进生殖芽尖的器官发生。ETT和ARF4直接抑制STM基因，而MP通过其靶基因FIL间接发挥作用。本文的数据显示，正如动物中的情况，植物的多能性下调对于器官发生是非常重要的。

通讯：Doris Wagner (https://www.bio.upenn.edu/people/doris-wagner)

个人简介：1995年，加州大学伯克利分校，博士。

研究方向：植物发育状态转变和响应环境信号时的细胞重编程。

doi: https://doi.org/10.1038/s41467-019-08861-3

Journal: Nature Communications

Published date: February 21, 2019