J Integr Plant Biol ›› 2020, Vol. 62 ›› Issue (5): 668-689.DOI: 10.1111/jipb.12933

• Plant-abiotic Interactions • Previous Articles     Next Articles

Oryza sativa FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (OsFIT/OsbHLH156) interacts with OsIRO2 to regulate iron homeostasis

Gang Liang1,2*, Huimin Zhang1, Yang Li1,2, Mengna Pu1,2, Yujie Yang1,2,3, Chenyang Li1,2,3, Chengkai Lu1,2, Peng Xu1,2,3 and Diqiu Yu1,4*   

  1. 1CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming 650223, China
    2Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla 666303, China
    3University of Chinese Academy of Sciences, Beijing 100049, China
    4State Key Laboratory for Conservation and Utilization of Bio‐Resources in Yunnan, Yunnan University, Kunming 650091, China

    Email: Gang Liang (lianggang@xtbg.ac.cn); Diqiu Yu (ydq@xtbg.ac.cn, Dr. Yu is fully responsible for the distribution of all materials associated with this article)
  • Received:2020-03-28 Accepted:2020-03-30 Online:2020-04-01 Published:2020-05-01


Iron (Fe) is indispensable for the growth and development of plants. It is well known that FER‐LIKE FE DEFICIENCY‐INDUCED TRANSCRIPTION FACTOR (FIT) is a key regulator of Fe uptake in Arabidopsis. Here, we identify the Oryza sativa FIT (also known as OsbHLH156) as the interacting partner of IRON‐RELATED BHLH TRANSCRIPTION FACTOR 2 (OsIRO2) that is critical for regulating Fe uptake. The OsIRO2 protein is localized in the cytoplasm and nucleus, but OsFIT facilitates the accumulation of OsIRO2 in the nucleus. Loss‐of‐function mutations of OsFIT result in decreased Fe accumulation, severe Fe‐deficiency symptoms, and disrupted expression of Fe‐uptake genes. In contrast, OsFIT overexpression promotes Fe accumulation and the expression of Fe‐uptake genes. Genetic analyses indicate that OsFIT and OsIRO2 function in the same genetic node. Further analyses suggest that OsFIT and OsIRO2 form a functional transcription activation complex to initiate the expression of Fe‐uptake genes. Our findings provide a mechanism understanding of how rice maintains Fe homeostasis.

OsIRO2 is a key regulator of Fe homeostasis in rice. Here we identified OsFIT as its interacting protein. They play the same biological roles in Fe deficiency response. OsFIT promotes the accumulation of OsIRO2 in the nucleus where the OsFIT‐OsIRO2 transcription complex initiates the transcription of Fe deficiency responsive genes.
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