Progressive chromatin silencing of ABA biosynthesis genes permits seed germination in Arabidopsis

第一作者：Deyue Yang

第一单位：南方科技大学

通讯作者：Zhe Wu

 Abstarct 

背景回顾：Seed germination represents a major developmental switch in plants that is vital to agriculture, but how this process is controlled at the chromatin level remains obscure. 

种子萌发是植物生活史中一个非常关键的发育转变，对于农业来说尤其重要，但是其在染色质的层面上是如何被调控的还不清楚。

主要发现：Here we demonstrate that successful germination in Arabidopsis thaliana requires a chromatin mechanism that progressively silences 9-CIS-EPOXYCAROTENOID DIOXYGENASE 6 (NCED6), which encodes a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, through the cooperative action of the RNA-binding protein RZ-1 and the polycomb repressive complex 2 (PRC2). 

本文中，作者发现拟南芥的种子成功萌发需要一种逐步沉默ABA生物合成限速酶编码基因NCED6的染色质调控机制，该过程需要RNA结合蛋白RZ-1和多梳抑制复合体PRC2的协同作用。

结果1-RZ-1和PRC2作用于种子萌发和NCEDs表达：Simultaneous inactivation of RZ-1 and PRC2 blocked germination and synergistically derepressed NCEDs and hundreds of genes. 

同时失活RZ-1和PRC2蛋白会导致种子萌发失败，并且协同去抑制NCEDs和数百个基因的表达。

结果2-RZ-1抑制NCED6表达：At NCED6, in part by promoting H3 deacetylation and suppressing H3K4me3, RZ-1 facilitates transcriptional silencing and also an H3K27me3 accumulation process that occurs during seed germination and early seedling growth.

在NCED6基因位点上，RZ-1蛋白部分通过促进H3去乙酰化和抑制H3K4me3，从而促进种子萌发过程和早期幼苗发育过程中NCED6的转录沉默和H3K27me3的积累。

结果3-RZ-1互补并协同PRC2：Genome-wide analysis revealed that RZ-1 is preferentially required for transcriptional silencing of many PRC2 targets early during seed germination, when H3K27me3 is not yet established. 

全基因组范围的分析显示，在种子萌发早期，当H3K27me3尚未建立时，很多由PRC2介导沉默的靶点其转录沉默需要RZ-1蛋白。

结论：We propose RZ-1 confers a novel silencing mechanism to compensate for and synergize with PRC2. Our work highlights the progressive chromatin silencing of ABA biosynthesis genes via the RNA-binding protein RZ1 and PRC2 acting in synergy, a process that is vital for seed germination.

因此，作者提出RZ-1介导了一种新的沉默机制，从而互补并与PRC2一起协同作用于靶向基因的沉默。本文的研究结果揭示了RNA结合蛋白RZ-1和PRC2蛋白协同作用于ABA合成基因的逐步染色质沉默，从而保证种子的顺利萌发。

** 吴 柘 **

doi: https://doi.org/10.1093/plcell/koac134

Journal: The Plant Cell

 Published date: May 06, 2022

CITE

Deyue Yang, Fengli Zhao, Danling Zhu, Xi Chen, Xiangxiong Kong, Yufeng Wu, Min Chen, Jiamu Du, Li-Jia Qu, Zhe Wu, Progressive chromatin silencing of ABA biosynthesis genes permits seed germination in Arabidopsis. The Plant Cell, 2022. DOI: https://doi.org/10.1093/plcell/koac134.​