Plant Molecular Science and Centre of Systems and Synthetic Biology, Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
Center for Sustainable Resource Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan.
BMC Biol. 2022 Apr 11;20(1):83. doi: 10.1186/s12915-022-01273-8.
Jasmonates (JAs) mediate trade-off between responses to both biotic and abiotic stress and growth in plants. The Arabidopsis thaliana HISTONE DEACETYLASE 6 is part of the CORONATINE INSENSITIVE1 receptor complex, co-repressing the HDA6/COI1-dependent acetic acid-JA pathway that confers plant drought tolerance. The decrease in HDA6 binding to target DNA mirrors histone H4 acetylation (H4Ac) changes during JA-mediated drought response, and mutations in HDA6 also cause depletion in the constitutive repressive marker H3 lysine 27 trimethylation (H3K27me3). However, the genome-wide effect of HDA6 on H4Ac and much of the impact of JAs on histone modifications and chromatin remodelling remain elusive.
We performed high-throughput ChIP-Seq on the HDA6 mutant, axe1-5, and wild-type plants with or without methyl jasmonate (MeJA) treatment to assess changes in active H4ac and repressive H3K27me3 histone markers. Transcriptional regulation was investigated in parallel by microarray analysis in the same conditions. MeJA- and HDA6-dependent histone modifications on genes for specialized metabolism; linolenic acid and phenylpropanoid pathways; and abiotic and biotic stress responses were identified. H4ac and H3K27me3 enrichment also differentially affects JAs and HDA6-mediated genome integrity and gene regulatory networks, substantiating the role of HDA6 interacting with specific families of transposable elements in planta and highlighting further specificity of action as well as novel targets of HDA6 in the context of JA signalling for abiotic and biotic stress responses.
The findings demonstrate functional overlap for MeJA and HDA6 in tuning plant developmental plasticity and response to stress at the histone modification level. MeJA and HDA6, nonetheless, maintain distinct activities on histone modifications to modulate genetic variability and to allow adaptation to environmental challenges.
茉莉酸（JAs）介导植物对生物和非生物胁迫以及生长的反应之间的权衡。拟南芥 HISTONE DEACETYLASE 6 是 CORONATINE INSENSITIVE1 受体复合物的一部分，共同抑制依赖 HDA6/COI1 的乙酸-JA 途径，该途径赋予植物耐旱性。HDA6 与靶 DNA 的结合减少反映了茉莉酸介导的干旱响应过程中组蛋白 H4 乙酰化（H4Ac）的变化，HDA6 的突变也导致组成性抑制标记 H3 赖氨酸 27 三甲基化（H3K27me3）耗尽。然而，HDA6 对 H4Ac 的全基因组影响以及 JAs 对组蛋白修饰和染色质重塑的大部分影响仍不清楚。
我们在有或没有茉莉酸甲酯（MeJA）处理的 HDA6 突变体 axe1-5 和野生型植物上进行了高通量 ChIP-Seq，以评估活性 H4ac 和抑制性 H3K27me3 组蛋白标记的变化。在相同条件下，通过微阵列分析平行研究了转录调控。鉴定了专门代谢途径、亚麻酸和苯丙烷途径以及非生物和生物胁迫反应的基因的 MeJA 和 HDA6 依赖性组蛋白修饰。H4ac 和 H3K27me3 富集也会对 JAs 和 HDA6 介导的基因组完整性和基因调控网络产生不同的影响，这证实了 HDA6 与特定转座元件家族相互作用在植物体内的作用，并强调了 HDA6 在 JA 信号转导中对非生物和生物胁迫反应的特定作用和新靶点。
这些发现表明，MeJA 和 HDA6 在调节植物发育可塑性和在组蛋白修饰水平上对胁迫的反应方面存在功能重叠。然而，MeJA 和 HDA6 在调节遗传可变性和适应环境挑战方面保持了不同的组蛋白修饰活性。
