Iron (Fe) deficient plants employ multiple strategies to increase root uptake and root‐to‐shoot translocation of Fe. The identification of genes that are responsible for these processes, and a comprehensive understanding of the regulatory effects of transcriptional networks on their expression, including transcription factors (TFs), is underway in Arabidopsis thaliana. Here, we show that a Histone‐ or heme‐associated proteins (HAP) transcription factor (TF), HAP5A, is necessary for the response to Fe deficiency in Arabidopsis. Its expression was induced under Fe deficiency, and the lack of HAP5A significantly decreased Fe translocation from the root to the shoot, resulting in substantial chlorosis of the newly expanded leaves, compared with the wild‐type (WT, Col‐0). Further analysis found that the expression of a gene encoding nicotianamine (NA) synthase (NAS1) was dramatically decreased in the hap5a mutant, regardless of the Fe status. Yeast‐one‐hybrid and ChIP analyses suggested that HAP5A directly binds to the promoter region of NAS1. Moreover, overexpression of NAS1 could rescue the chlorosis phenotype of hap5a in Fe deficient conditions. In summary, a novel pathway was elucidated, showing that NAS1‐dependent translocation of Fe from the root to the shoot is controlled by HAP5A in Fe‐deficient Arabidopsis thaliana.

中文翻译：

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AtHAP5A调节缺铁拟南芥中的铁转运

铁（Fe）缺乏的植物采用多种策略来增加铁的根吸收量和根向茎的转运。在拟南芥中，正在鉴定负责这些过程的基因，并全面了解转录网络对其表达的调控作用，包括转录因子（TF）。在这里，我们表明，组蛋白或血红素相关蛋白（HAP）转录因子（TF）HAP5A对于拟南芥中铁缺乏症的响应是必需的。在铁缺乏和缺乏HAP5A的情况下诱导其表达与野生型（WT，Col-0）相比，铁从根到芽的易位明显降低，从而导致新扩张的叶片发生大量的绿化。进一步的分析发现，在hap5a突变体中，无论Fe的状态如何，编码烟碱胺（NA）合酶（NAS1）的基因的表达都大大降低。酵母单杂交和ChIP分析表明HAP5A直接与NAS1的启动子区域结合。此外，NAS1的过表达可以挽救hap5a的萎黄病表型在铁缺乏的情况下。总之，阐明了一条新途径，表明在缺铁的拟南芥中，HAP5A控制了铁从根到芽的NAS1依赖性转运。