Xing Yingying, Li Yawen, Gui Xinmeng, Zhang Xianyu, Hu Qian, Zhao Qiqi, Qiao Yongli, Xu Ning, Liu Jun
State Key Laboratory of Agricultural and Forestry Biosecurity, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China.
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2025 Apr 29;16(1):3988. doi: 10.1038/s41467-025-59334-9.
Chilling stress is one of the major environmental stresses that restrains plant development and growth. Our previous study showed that a potential iron sensor BTS (BRUTUS) was involved in temperature response in Arabidopsis plants. However, whether plant iron homeostasis is involved in plant response to temperature fluctuation is not known. In this study, we discover that BTS mutant bts-2 is sensitive to chilling stress, and the sensitivity is attributed to the accumulation of iron. The suppressor screening of bts-2 led to the discovery of RH24, a DEAD-box RNA helicase, that fully suppresses bts-2 chilling sensitivity. RH24 is accumulated under low temperatures, where it unwinds the iron regulator ILR3 (IAA-leucine resistant 3) mRNA and increases the ILR3 protein levels. Intriguingly, RH24 sequesters ILR3 in phase-separated condensates to reduce ILR3-mediated iron overload, and BTS or cold treatments further facilitated the condensate formation. Therefore, RH24 and BTS coordinately control ILR3 to reduce iron uptake under chilling stress. Our findings reveal that the RNA helicase RH24 and BTS finetunes ILR3 to maintain plant iron homeostasis in response to temperature fluctuations.
低温胁迫是限制植物发育和生长的主要环境胁迫之一。我们之前的研究表明，一种潜在的铁传感器BTS（BRUTUS）参与了拟南芥植物的温度响应。然而，植物铁稳态是否参与植物对温度波动的响应尚不清楚。在本研究中，我们发现BTS突变体bts-2对低温胁迫敏感，且这种敏感性归因于铁的积累。对bts-2进行的抑制子筛选导致发现了一种DEAD-box RNA解旋酶RH24，它能完全抑制bts-2的低温敏感性。RH24在低温下积累，在那里它解开铁调节因子ILR3（IAA-亮氨酸抗性3）的mRNA并增加ILR3蛋白水平。有趣的是，RH24将ILR3隔离在相分离的凝聚物中以减少ILR3介导的铁过载，而BTS或冷处理进一步促进了凝聚物的形成。因此，RH24和BTS在低温胁迫下协同控制ILR3以减少铁的吸收。我们的研究结果表明，RNA解旋酶RH24和BTS微调ILR3以在响应温度波动时维持植物铁稳态。
