Iron homeostasis in Arabidopsis thaliana: transcriptomic analyses reveal novel FIT-regulated genes, iron deficiency marker genes and functional gene networks

Brassinosteroids (BRs) are plant hormones that play an essential role in plant development and have the ability to protect plants against various environmental stresses, such as low and high temperature, drought, heat, salinity, heavy metal toxicity, and pesticides. Mitigation of stress effects are produced through independent mechanisms or by interaction with other important phytohormones. However, there are few studies in which this property has been reported for BRs analogs. Thus, in this work, the enhancement of drought stress tolerance of A. thaliana was assessed for a series of 2-deoxybrassinosteroid analogs. In addition, the growth-promoting activity in the Rice Lamina Inclination Test (RLIT) was also evaluated. The results show that analog 1 exhibits similar growth activity as brassinolide (BL; used as positive control) in the RLIT bioassay. Interestingly, both compounds increase their activities by a factor of 1.2–1.5 when they are incorporated to polymer micelles formed by Pluronic F-127. On the other hand, tolerance to water deficit stress of Arabidopsis thaliana seedlings was evaluated by determining survival rate and dry weight of seedlings after the recovery period. In both cases, the effect of analog 1 is higher than that exhibited by BL. Additionally, the expression of a subset of drought stress marker genes was evaluated in presence and absence of exogenous applied BRs. Results obtained by qRT-PCR analysis, indicate that transcriptional changes of AtDREBD2A and AtNCED3 genes were more significant in A. thaliana treated with analog 1 in homogeneous solution than in that treated with BL. These changes suggest the activation of alternative pathway in response to water stress deficit. Thus, exogenous application of BRs synthetic analogs could be a potential tool for improvement of crop production under stress conditions.

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Responses of Arabidopsis thaliana to bicarbonate-induced iron deficiency

Acta Physiologiae Plantarum ◽

10.1007/s11738-009-0318-z ◽

2009 ◽

Vol 31 (4) ◽

pp. 849-853 ◽

Cited By ~ 14

Author(s):

Najoua Msilini ◽

Houneida Attia ◽

Najoua Bouraoui ◽

Sabah M’rah ◽

Riadh Ksouri ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Iron Deficiency

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IRON MAN interacts with BRUTUS to maintain iron homeostasis in Arabidopsis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2109063118 ◽

2021 ◽

Vol 118 (39) ◽

pp. e2109063118

Author(s):

Yang Li ◽

Cheng Kai Lu ◽

Chen Yang Li ◽

Ri Hua Lei ◽

Meng Na Pu ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Transcription Factors ◽

Iron Homeostasis ◽

Fe Deficiency ◽

Small Peptides ◽

Interaction Domain ◽

C Terminus ◽

Positive Regulators ◽

Fe Homeostasis ◽

And Function

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.

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Wheat TaVIT2D restores phenotype and mediates iron homeostasis during growth of Arabidopsis thaliana in iron-deficient conditions

Plant Physiology Reports ◽

10.1007/s40502-018-0426-0 ◽

2018 ◽

Vol 24 (1) ◽

pp. 24-34

Author(s):

Raja Jeet ◽

Sudhir P. Singh ◽

Siddharth Tiwari ◽

Promila Pathak

Keyword(s):

Arabidopsis Thaliana ◽

Iron Homeostasis ◽

Iron Deficient

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Iron Homeostasis and Disorders in Dogs and Cats: A Review

Journal of the American Animal Hospital Association ◽

10.5326/jaaha-ms-5553 ◽

2011 ◽

Vol 47 (3) ◽

pp. 151-160 ◽

Cited By ~ 27

Author(s):

Jennifer L. McCown ◽

Andrew J. Specht

Keyword(s):

Iron Deficiency ◽

Iron Overload ◽

Iron Homeostasis ◽

Diagnostic Testing ◽

Clinical Manifestations ◽

Essential Element ◽

The Body ◽

Deficiency Anemia ◽

Enzyme Systems ◽

Living Organisms

Iron is an essential element for nearly all living organisms and disruption of iron homeostasis can lead to a number of clinical manifestations. Iron is used in the formation of both hemoglobin and myoglobin, as well as numerous enzyme systems of the body. Disorders of iron in the body include iron deficiency anemia, anemia of inflammatory disease, and iron overload. This article reviews normal iron metabolism, disease syndromes of iron imbalance, diagnostic testing, and treatment of either iron deficiency or excess. Recent advances in diagnosing iron deficiency using reticulocyte indices are reviewed.

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In Vitro Analysis of Protein-Operator Interactions of the NikR and Fur Metal-Responsive Regulators of Coregulated Genes in Helicobacter pylori

Journal of Bacteriology ◽

10.1128/jb.187.22.7703-7715.2005 ◽

2005 ◽

Vol 187 (22) ◽

pp. 7703-7715 ◽

Cited By ~ 70

Author(s):

Isabel Delany ◽

Raffaele Ieva ◽

Alice Soragni ◽

Markus Hilleringmann ◽

Rino Rappuoli ◽

...

Keyword(s):

Helicobacter Pylori ◽

Binding Site ◽

Gene Networks ◽

Iron Homeostasis ◽

Molecular Mechanisms ◽

Target Genes ◽

Target Sequence ◽

Gene Promoters ◽

Direct Role ◽

H Pylori

ABSTRACT Two important metal-responsive regulators, NikR and Fur, are involved in nickel and iron homeostasis and controlling gene expression in Helicobacter pylori. To date, they have been implicated in the regulation of sets of overlapping genes. We have attempted here dissection of the molecular mechanisms involved in transcriptional regulation of the NikR and Fur proteins, and we investigated protein-promoter interactions of the regulators with known target genes. We show that H. pylori NikR is a tetrameric protein and, through DNase I footprinting analysis, we have identified operators for NikR to which it binds with different affinities in a metal-responsive way. Mapping of the NikR binding site upstream of the urease promoter established a direct role for NikR as a positive regulator of transcription and, through scanning mutagenesis of this binding site, we have determined two subsites that are important for the binding of the protein to its target sequence. Furthermore, by alignment of the operators for NikR, we have shown that the H. pylori protein recognizes a sequence that is distinct from its well-studied orthologue in Escherichia coli. Moreover, we show that NikR and Fur can bind independently at distinct operators and also compete for overlapping operators in some coregulated gene promoters, adding another dimension to the previous suggested link between iron and nickel regulation. Finally, the importance of an interconnection between metal-responsive gene networks for homeostasis is discussed.

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Modulation of intestinal sulfur assimilation metabolism regulates iron homeostasis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1715302115 ◽

2018 ◽

Vol 115 (12) ◽

pp. 3000-3005 ◽

Cited By ~ 7

Author(s):

Benjamin H. Hudson ◽

Andrew T. Hale ◽

Ryan P. Irving ◽

Shenglan Li ◽

John D. York

Keyword(s):

Iron Deficiency ◽

Iron Deficiency Anemia ◽

Iron Reduction ◽

Genetic Basis ◽

Iron Homeostasis ◽

Deficiency Anemia ◽

Sulfur Assimilation ◽

Nucleotide Hydrolysis ◽

Evolutionarily Conserved ◽

Organismal Development

Sulfur assimilation is an evolutionarily conserved pathway that plays an essential role in cellular and metabolic processes, including sulfation, amino acid biosynthesis, and organismal development. We report that loss of a key enzymatic component of the pathway, bisphosphate 3′-nucleotidase (Bpnt1), in mice, both whole animal and intestine-specific, leads to iron-deficiency anemia. Analysis of mutant enterocytes demonstrates that modulation of their substrate 3′-phosphoadenosine 5′-phosphate (PAP) influences levels of key iron homeostasis factors involved in dietary iron reduction, import and transport, that in part mimic those reported for the loss of hypoxic-induced transcription factor, HIF-2α. Our studies define a genetic basis for iron-deficiency anemia, a molecular approach for rescuing loss of nucleotidase function, and an unanticipated link between nucleotide hydrolysis in the sulfur assimilation pathway and iron homeostasis.

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