Wang Wujian, He Fengyu, Zhang Hui, Yang Yue, Wang Xiaojuan, Fu Yue, Shou Huixia, Zheng Luqing
College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 China.
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058 China.
aBIOTECH. 2025 Mar 3;6(2):215-231. doi: 10.1007/s42994-025-00203-w. eCollection 2025 Jun.
Iron (Fe) homeostasis in plant cells is crucial for crop productivity and quality. An intricate transcriptional network involving numerous basic Helix-Loop-Helix (bHLH) transcription factors has been proposed to control Fe homeostasis. In the present study, we characterized rice () OsbHLH062, a member of the IVb subgroup of the bHLH family, demonstrating that it negatively regulates Fe-deficiency responses. OsbHLH062 represses transcription by recruiting TOPLESS/TOPLESS-RELATED co-repressors (TPL/TPRs) through its ethylene-responsive element binding factor-associated amphiphilic repression (EAR) motif. Under Fe deficiency, the expression of is upregulated in roots and downregulated in shoots. Overexpression of leads to decreased Fe accumulation in the shoot. Furthermore, OsbHLH062 interacts with POSITIVE REGULATOR OF IRON HOMEOSTASIS 1 (OsPRI1) and inhibits its transactivation activity, thereby negatively regulating the expression of many Fe homeostasis-related genes. These results indicate an important role for OsbHLH062 in regulating Fe homeostasis by negatively regulating Fe deficiency responses in rice. This knowledge will aid in the design of Fe-biofortified rice plants that can help to address the global issue of Fe deficiency.
植物细胞中的铁（Fe）稳态对于作物产量和品质至关重要。人们提出了一个涉及众多基本螺旋-环-螺旋（bHLH）转录因子的复杂转录网络来控制铁稳态。在本研究中，我们对水稻（）的OsbHLH062进行了表征，它是bHLH家族IVb亚组的成员，表明它对缺铁反应起负调控作用。OsbHLH062通过其乙烯反应元件结合因子相关两亲性抑制（EAR）基序招募TOPLESS/TOPLESS相关共抑制因子（TPL/TPRs）来抑制转录。在缺铁条件下，在根中上调表达，在地上部下调表达。的过表达导致地上部铁积累减少。此外，OsbHLH062与铁稳态正向调节因子1（OsPRI1）相互作用并抑制其反式激活活性，从而负调控许多铁稳态相关基因的表达。这些结果表明OsbHLH062在通过负调控水稻缺铁反应来调节铁稳态中起重要作用。这一知识将有助于设计铁生物强化水稻植株，有助于解决全球缺铁问题。
