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

2020 ◽  
Vol 62 (5) ◽  
pp. 668-689 ◽  
Author(s):  
Gang Liang ◽  
Huimin Zhang ◽  
Yang Li ◽  
Mengna Pu ◽  
Yujie Yang ◽  
...  
2020 ◽  
Author(s):  
Gang Liang ◽  
Huimin Zhang ◽  
Yang Li ◽  
Mengna Pu ◽  
Yujie Yang ◽  
...  

ABSTRACTThere are two Fe-uptake strategies for maintaining Fe homeostasis in plants. As a special graminaceous plant, rice applies both strategies. However, it remains unclear how these two strategies are regulated in rice. IRON-RELATED BHLH TRANSCRIPTION FACTOR 2 (OsIRO2) is critical for regulating Fe uptake in rice. In this study, we identified an interacting partner of OsIRO2, Oryza sativa FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (OsFIT), which encodes a bHLH transcription factor. The OsIRO2 protein is localized in the cytoplasm and nucleus, but OsFIT facilitates the accumulation of OsIRO2 in the nucleus. Loss-of-function mutations to 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 indicated that OsFIT and OsIRO2 function in the same genetic node. Further analysis suggested 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.One-sentence summaryOsFIT interacts with and facilitates the accumulation of OsIRO2 in the nucleus where the OsFIT-OsIRO2 transcription complex initiates the transcription of Fe deficiency responsive genes.


2021 ◽  
Vol 118 (39) ◽  
pp. e2109063118
Author(s):  
Yang Li ◽  
Cheng Kai Lu ◽  
Chen Yang Li ◽  
Ri Hua Lei ◽  
Meng Na Pu ◽  
...  

IRON MAN (IMA) peptides, a family of small peptides, control iron (Fe) transport in plants, but their roles in Fe signaling remain unclear. BRUTUS (BTS) is a potential Fe sensor that negatively regulates Fe homeostasis by promoting the ubiquitin-mediated degradation of bHLH105 and bHLH115, two positive regulators of the Fe deficiency response. Here, we show that IMA peptides interact with BTS. The C-terminal parts of IMA peptides contain a conserved BTS interaction domain (BID) that is responsible for their interaction with the C terminus of BTS. Arabidopsis thaliana plants constitutively expressing IMA genes phenocopy the bts-2 mutant. Moreover, IMA peptides are ubiquitinated and degraded by BTS. bHLH105 and bHLH115 also share a BID, which accounts for their interaction with BTS. IMA peptides compete with bHLH105/bHLH115 for interaction with BTS, thereby inhibiting the degradation of these transcription factors by BTS. Genetic analyses suggest that bHLH105/bHLH115 and IMA3 have additive roles and function downstream of BTS. Moreover, the transcription of both BTS and IMA3 is activated directly by bHLH105 and bHLH115 under Fe-deficient conditions. Our findings provide a conceptual framework for understanding the regulation of Fe homeostasis: IMA peptides protect bHLH105/bHLH115 from degradation by sequestering BTS, thereby activating the Fe deficiency response.


2018 ◽  
Vol 219 (1) ◽  
pp. 149-162 ◽  
Author(s):  
Ge Zi Li ◽  
Zhan Qi Wang ◽  
Kengo Yokosho ◽  
Bing Ding ◽  
Wei Fan ◽  
...  

2020 ◽  
Vol 71 (5) ◽  
pp. 1694-1705 ◽  
Author(s):  
Birte Schwarz ◽  
Petra Bauer

Abstract Iron (Fe) is vital for plant growth. Plants balance the beneficial and toxic effects of this micronutrient, and tightly control Fe uptake and allocation. Here, we review the role of the basic helix–loop–helix (bHLH) transcription factor FIT (FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR) in Fe acquisition. FIT is not only essential, it is also a central regulatory hub in root cells to steer and adjust the rate of Fe uptake by the root in a changing environment. FIT regulates a subset of root Fe deficiency (–Fe) response genes. Based on a combination of co-expression network and FIT-dependent transcriptome analyses, we defined a set of FIT-dependent and FIT-independent gene expression signatures and co-expression clusters that encode specific functions in Fe regulation and Fe homeostasis. These gene signatures serve as markers to integrate novel regulatory factors and signals into the –Fe response cascade. FIT forms a complex with bHLH subgroup Ib transcription factors. Furthermore, it interacts with key regulators from different signaling pathways that either activate or inhibit FIT function to adjust Fe acquisition to growth and environmental constraints. Co-expression clusters and FIT protein interactions suggest a connection of –Fe with ABA responses and root cell elongation processes that can be explored in future studies.


mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Yonglin Wang ◽  
Chenglin Deng ◽  
Longyan Tian ◽  
Dianguang Xiong ◽  
Chengming Tian ◽  
...  

ABSTRACT Iron homeostasis is essential for full virulence and viability in many pathogenic fungi. Here, we showed that the bZip transcription factor VdHapX functions as a key regulator of iron homeostasis for adaptation to iron-depleted and iron-excess conditions and is required for full virulence in the vascular wilt fungus, Verticillium dahliae. Deletion of VdHapX impaired mycelial growth and conidiation under both iron starvation and iron sufficiency. Furthermore, disruption of VdHapX led to decreased formation of the long-lived survival structures of V. dahliae, known as microsclerotia. Expression of genes involved in iron utilization pathways and siderophore biosynthesis was misregulated in the ΔVdHapX strain under the iron-depleted condition. Additionally, the ΔVdHapX strain exhibited increased sensitivity to high iron concentrations and H2O2, indicating that VdHapX also contributes to iron or H2O2 detoxification. The ΔVdHapX strain showed a strong reduction in virulence on smoke tree seedlings (Cotinus coggygria) and was delayed in its ability to penetrate plant epidermal tissue. IMPORTANCE This study demonstrated that VdHapX is a conserved protein that mediates adaptation to iron starvation and excesses, affects microsclerotium formation, and is crucial for virulence of V. dahliae.


2009 ◽  
Vol 53 (4) ◽  
pp. 643-649 ◽  
Author(s):  
F. Gao ◽  
J. -M. Chen ◽  
A. -S. Xiong ◽  
R. -H. Peng ◽  
J. -G. Liu ◽  
...  

2019 ◽  
Vol 33 (12) ◽  
pp. 13450-13464 ◽  
Author(s):  
Sidi Yang ◽  
Qifeng Deng ◽  
Lanqing Sun ◽  
Kedi Dong ◽  
Yuanyuan Li ◽  
...  

Blood ◽  
2010 ◽  
Vol 116 (22) ◽  
pp. 4657-4664 ◽  
Author(s):  
Marie-Berengere Troadec ◽  
Diane McVey Ward ◽  
Eric Lo ◽  
Jerry Kaplan ◽  
Ivana De Domenico

Ferroportin (Fpn) is the only known iron exporter in vertebrate cells and plays a critical role in iron homeostasis regulating cytosolic iron levels and exporting iron to plasma. Ferroportin1 (FPN1) expression can be transcriptionally regulated by iron as well as other transition metals. Fpn can also be posttranslationally regulated by hepcidin-mediated internalization and degradation. We demonstrate that zinc and cadmium induce FPN1 transcription through the action of Metal Transcription Factor-1 (MTF-1). These transition metals induce MTF-1 translocation into the nucleus. Zinc leads to MTF-1 binding to the FPN1 promoter, while iron does not. Silencing of MTF-1 reduces FPN1 transcription in response to zinc but not in response to iron. The mouse FPN1 promoter contains 2 MTF-1 binding sites and mutation of those sites affects the zinc and cadmium-dependent expression of a FPN1 promoter reporter construct. We demonstrate that Fpn can transport zinc and can protect zinc sensitive cells from high zinc toxicity.


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