Because Iron (Fe) is an essential element, Fe storage in plant seeds is necessary for seedling establishment following germination. However, the mechanisms controlling seed Fe storage during seed development remain largely unknown. Here we reveal that an ERF95 transcription factor regulates Arabidopsis seed Fe accumulation. We show that expression of ERF95 increases during seed maturation, and that lack of ERF95 reduces seed Fe accumulation, consequently increasing sensitivity to Fe deficiency during seedling establishment. Conversely, overexpression of ERF95 has the opposite effects. We show that lack of ERF95 decreases abundance of FER1 messenger RNA in developing seed, which encodes Fe‐sequestering ferritin. Accordingly, a fer1‐1 loss‐of‐function mutation confers reduced seed Fe accumulation, and suppresses ERF95‐promoted seed Fe accumulation. In addition, ERF95 binds to specific FER1 promoter GCC‐boxes and transactivates FER1 expression. We show that ERF95 expression in maturing seed is dependent on EIN3, the master transcriptional regulator of ethylene signaling. While lack of EIN3 reduces seed Fe content, overexpression of ERF95 rescues Fe accumulation in the seed of ein3 loss‐of‐function mutant. Finally, we show that ethylene production increases during seed maturation. We conclude that ethylene promotes seed Fe accumulation during seed maturation via an EIN3‐ERF95‐FER1‐dependent signaling pathway.

中文翻译：

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乙烯通过ERF95转录因子促进拟南芥种子成熟过程中的种子铁存储。

由于铁（Fe）是必不可少的元素，因此发芽后的幼苗生长需要将植物种子中的铁储存起来。然而，在种子发育过程中控制种子铁储存的机制仍然是未知的。在这里，我们揭示了ERF95转录因子调节拟南芥种子铁的积累。我们表明，ERF95的表达在种子成熟过程中增加，而缺乏ERF95则减少了种子中铁的积累，因此在幼苗建立过程中增加了对铁缺乏的敏感性。相反，ERF95的过表达具有相反的作用。我们证明缺乏ERF95会降低发育中的种子中的FER1信使RNA的丰度，该种子编码铁螯合铁蛋白。因此，fer1-1功能丧失突变可减少种子铁的积累，并抑制ERF95促进的种子铁的积累。此外，ERF95与特定的FER1启动子GCC-box结合并反激活FER1表达。我们显示，ERF95在成熟种子中的表达依赖于EIN3，乙烯信号的主要转录调节因子。EIN3的缺乏会降低种子中的铁含量，而ERF95的过表达可以挽救功能缺失的Ein3突变体种子中的铁积累。最后，我们证明了种子成熟过程中乙烯的产量增加。我们得出结论，乙烯通过EIN3-ERF95-FER1依赖性信号通路促进种子在成熟过程中的铁积累。