Division of Biological Science, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan.
RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan.
Plant Cell Environ. 2019 Jul;42(7):2198-2214. doi: 10.1111/pce.13547. Epub 2019 Apr 12.
After germination, seedlings undergo growth arrest in response to unfavourable conditions, a critical adaptation enabling plants to survive harsh environments. The plant hormone abscisic acid (ABA) plays a key role in this arrest. To arrest growth, ABA-dependent transcription factors change gene expression patterns in a flexible and reversible manner. Although the control of gene expression has important roles in growth arrest, the epigenetic mechanisms in the response to ABA are not fully understood. Here, we show that the histone demethylases JUMONJI-C domain-containing protein 30 (JMJ30) and JMJ32 control ABA-mediated growth arrest in Arabidopsis thaliana. During the postgermination stage (2-3 days after germination), the ABA-dependent transcription factor ABA-insensitive3 (ABI3) activates the expression of JMJ30 in response to ABA. JMJ30 then removes a repressive histone mark, H3 lysine 27 trimethylation (H3K27me3), from the SNF1-related protein kinase 2.8 (SnRK2.8) promoter, and hence activates SnRK2.8 expression. SnRK2.8 encodes a kinase that activates ABI3 and is responsible for JMJ30- and JMJ32-mediated growth arrest. A feed-forward loop involving the ABI3 transcription factor, JMJ histone demethylases, and the SnRK2.8 kinase fine-tunes ABA-dependent growth arrest in the postgermination phase. Our findings highlight the importance of the histone demethylases in mediating adaptation of plants to the environment.
种子萌发后，幼苗会在不利条件下经历生长停滞，这是植物在恶劣环境中生存的关键适应机制。植物激素脱落酸（ABA）在这种停滞中起着关键作用。为了停止生长，ABA 依赖的转录因子以灵活和可逆的方式改变基因表达模式。尽管基因表达的调控在生长停滞中起着重要作用，但 ABA 响应中的表观遗传机制尚未完全了解。在这里，我们表明组蛋白去甲基酶 JUMONJI-C 结构域蛋白 30（JMJ30）和 JMJ32 控制拟南芥中 ABA 介导的生长停滞。在萌发后阶段（萌发后 2-3 天），ABA 不敏感 3（ABI3）转录因子在 ABA 响应中激活 JMJ30 的表达。JMJ30 随后从 SNF1 相关蛋白激酶 2.8（SnRK2.8）启动子上去除抑制性组蛋白标记 H3 赖氨酸 27 三甲基化（H3K27me3），从而激活 SnRK2.8 的表达。SnRK2.8 编码一种激酶，激活 ABI3，负责 JMJ30 和 JMJ32 介导的生长停滞。涉及 ABI3 转录因子、JMJ 组蛋白去甲基酶和 SnRK2.8 激酶的正反馈回路微调了萌发后阶段 ABA 依赖的生长停滞。我们的研究结果强调了组蛋白去甲基酶在介导植物适应环境中的重要性。
