Maruoka Takashi, Gan Eng-Seng, Otsuka Nana, Shirakawa Makoto, Ito Toshiro
Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Japan.
Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.
Front Plant Sci. 2022 Jul 1;13:837831. doi: 10.3389/fpls.2022.837831. eCollection 2022.
Vernalization is the promotion of flowering after prolonged exposure to cold. In , vernalization induces epigenetic silencing of the floral repressor gene (). Among the repressive epigenetic marks, the trimethylation of lysine 27 on histone H3 proteins (H3K27me3) is a critical contributor to the epigenetic silencing of . The deposition of H3K27me3 is mediated by Polycomb Repressive Complex 2 (PRC2). Conversely, the elimination of H3K27me3 is mediated by histone demethylases, Jumonji-C domain-containing protein JMJ30 and its homolog JMJ32. However, the role of JMJ30 and JMJ32 in vernalization is largely unknown. In this study, we found that cold treatment dramatically reduced the expression levels of and did not reduce those of JMJ32. Next, by using the genetic approach, we found that the flowering of was accelerated under moderate vernalized conditions. Under moderate vernalized conditions, the silencing of occurred more quickly in than in the wild type. These results suggested that the histone demethylases JMJ30 and JMJ32 brake vernalization through the activation of . Our study suggested that PRC2 and Jumonji histone demethylases act in an opposing manner to regulate flowering time via epigenetic modifications.
春化作用是指植物在长时间暴露于低温后促进开花的现象。在[具体植物名称未给出]中，春化作用诱导了 floral repressor gene（[具体基因名称未给出]）的表观遗传沉默。在抑制性表观遗传标记中，组蛋白 H3 蛋白上赖氨酸 27 的三甲基化（H3K27me3）是[具体基因名称未给出]表观遗传沉默的关键因素。H3K27me3 的沉积由多梳抑制复合体 2（PRC2）介导。相反，H3K27me3 的消除由组蛋白去甲基化酶、含 Jumonji-C 结构域的蛋白 JMJ30 及其同源物 JMJ32 介导。然而，JMJ30 和 JMJ32 在春化作用中的作用在很大程度上尚不清楚。在本研究中，我们发现冷处理显著降低了[具体基因名称未给出]的表达水平，但并未降低 JMJ32 的表达水平。接下来，通过遗传学方法，我们发现[具体植物名称未给出]在适度春化条件下开花加速。在适度春化条件下，[具体植物名称未给出]中[具体基因名称未给出]的沉默比野生型发生得更快。这些结果表明，组蛋白去甲基化酶 JMJ30 和 JMJ32 通过激活[具体基因名称未给出]来抑制春化作用。我们的研究表明，PRC2 和 Jumonji 组蛋白去甲基化酶以相反的方式通过表观遗传修饰来调节开花时间。
