Singh Surjit, Kailasam Sakthivel, Lo Jing-Chi, Yeh Kuo-Chen
Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan.
Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung Hsing University, Taipei, 11529, Taiwan.
New Phytol. 2021 Apr;230(1):244-258. doi: 10.1111/nph.17130. Epub 2021 Jan 2.
Iron (Fe) homeostasis in plants is controlled by both transcription factors (TFs) and chromatin remodeling through histone modification. To date, few studies have reported the existence of histone modification in maintaining the Fe-deficiency response. However, the reports that do exist shed light on various histone modifications, but knowledge of the activation mark in Fe-deficiency response is lacking. By using a forward genetics approach, we identified a crucial allele for Fe-deficiency response, NON-RESPONSE TO Fe-DEFICIENCY2 (NRF2), previously described as EARLY FLOWERING8 (ELF8) associated with an activation mark on histone modification, histone H3 lysine4 trimethylation. In the nrf2-1 mutant, a point mutation at ELF8 , exhibits impaired expression of GENERAL REGULATORY FACTOR11 (GRF11) and downstream genes in the Fe-uptake pathway. In vivo chromatin immunoprecipitation revealed that in roots, NRF2/ELF8 is essential for the expression of GRF11 for Fe-deficiency response, whereas in shoots, NRF2/ELF8 regulates FLOWERING LOCUS C (FLC) expression for flowering time control. In summary, a key factor, NRF2/ELF8, involved in epigenetic regulation essential for both flowering time control and Fe-deficiency response is uncovered.
植物中的铁（Fe）稳态由转录因子（TFs）和通过组蛋白修饰的染色质重塑共同控制。迄今为止，很少有研究报道组蛋白修饰在维持缺铁反应中的存在。然而，现有的报道揭示了各种组蛋白修饰，但缺乏关于缺铁反应中激活标记的知识。通过正向遗传学方法，我们鉴定了一个对缺铁反应至关重要的等位基因，缺铁无反应2（NRF2），先前被描述为早花8（ELF8），与组蛋白修饰、组蛋白H3赖氨酸4三甲基化的激活标记相关。在nrf2-1突变体中，ELF8处的一个点突变，表现出铁吸收途径中通用调节因子11（GRF11）和下游基因的表达受损。体内染色质免疫沉淀显示，在根中，NRF2/ELF8对于缺铁反应中GRF11的表达至关重要，而在地上部分，NRF2/ELF8调节开花时间控制的开花位点C（FLC）表达。总之，发现了一个关键因子NRF2/ELF8，它参与了对开花时间控制和缺铁反应都至关重要的表观遗传调控。
