IRON MAN interacts with BRUTUS to maintain iron homeostasis in Arabidopsis

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.

scholarly journals Glutathione regulates subcellular iron homeostasis via transcriptional activation of iron responsive genes in Arabidopsis

2021 ◽  
Author(s):  
Ranjana Shee ◽  
Soumi Ghosh ◽  
Pinki Khan ◽  
Salman Sahid ◽  
Chandan Roy ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Transcriptional Activation ◽  
Iron Homeostasis ◽  
Fe Deficiency ◽  
Fe Content ◽  
Increased Sensitivity ◽  
Fe Homeostasis ◽  
Bhlh Transcription Factors ◽  
Dependent Pathway

Glutathione (GSH) is a ubiquitous molecule known to regulate various physiological and developmental phenomena in plants. Recently, its involvement in regulating iron (Fe) deficiency response was established in Arabidopsis. However, the role of GSH in modulating subcellular Fe homeostasis remained elusive. In this study, we dissected the role of GSH in regulating Fe homeostasis in Arabidopsis shoots under Fe limited conditions. The two GSH depleted mutants, cad2-1 and pad2-1 displayed increased sensitivity to Fe deficiency with smaller rosette diameter and higher chlorosis level compared with the Col-0 plants. Interestingly, the expression of the vacuolar Fe exporters, AtNRAMP3 and AtNRAMP4, chloroplast Fe importer, AtPIC1, along with AtFer1 and AtIRT1 were significantly down-regulated in these mutants. The expression of these genes were up-regulated in response to exogenous GSH treatment while treatment with BSO, a GSH inhibitor, down-regulated their expression. Moreover, the mutants accumulated higher Fe content in the vacuole and lower in the chloroplast compared with Col-0 under Fe limited condition suggesting a role of GSH in modulating subcellular Fe homeostasis. This regulation was, further, found to involve a GSNO-dependent pathway. Promoter analysis revealed that GSH induced the transcription of these genes presumably via S-nitrosylation of different Fe responsive bHLH transcription factors.

scholarly journals Functional Characterization Of The VAC14 Self-Interaction Domain

2021 ◽  
Author(s):  
Tamadher A. Alghamdi
Keyword(s):  
Functional Characterization ◽  
Regulatory Protein ◽  
Adaptor Protein ◽  
Interaction Domain ◽  
Lipid Kinase ◽  
Lipid Phosphatase ◽  
C Terminus ◽  
Regulatory Complex ◽  
Steady State Levels ◽  
And Function

PtdIns(3,5)P2 is a low-abundance signaling lipid present at < 0.1 % of total PtdIns lipids in yeasts and mammals. Reduced levels of PtdIns(3,5)P2 contributes to neurodegenerative disorders in humans and vacuolar defects in yeasts. Steady-state levels of PtdIns(3,5)P2 are dependent on both its rate of synthesis and turnover. In yeast, PtdIns(3,5)P2 is produced on the vacuole membrane by phosphorylation of PtdIns(3)P at the 5 position of its inositol ring by the Fab1 lipid kinase. Cells lacking Fab1 make no PtdIns(3,5)P2 and exhibit defects in vacuole morphology and function. The lipid phosphatase Fig4 counteracts Fab1 activity by turnover of PtdIns(3,5)P2 into PtdIns(3)P. Vac14 is a regulatory protein implicated in the synthesis and turnover of PtdIns(3,5)P2. It acts as an adaptor protein that controls both of Fab1 and Fig4 proteins. In addition, Vac14 exists as a multimer that allows for self-interaction. However, multimerization state of Vac14 as well as the domain responsible for self-interaction remained unknown. This study aimed to identify the self-interaction domain to elucidate its role in the assembly of the regulatory complex of PtdIns(3,5)P2. The observations seen in this study suggested that Vac14 self-interacts via multiple conserved motifs in the C-terminus, which are crucial for interaction with Fab1 and Fig4, and the normal morphology of yeast vacuoles.

Arabidopsis thaliana transcription factors MYB28 and MYB29 shape ammonium stress responses by regulating Fe homeostasis

2020 ◽  
Vol 229 (2) ◽  
pp. 1021-1035
Author(s):  
Inmaculada Coleto ◽  
Iraide Bejarano ◽  
Agustín Javier Marín‐Peña ◽  
Joaquín Medina ◽  
Cristina Rioja ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Stress Responses ◽  
Ammonium Stress ◽  
Fe Homeostasis

scholarly journals Two bHLH Transcription Factors, bHLH34 and bHLH104, Regulate Iron Homeostasis in Arabidopsis thaliana

2016 ◽  
Vol 170 (4) ◽  
pp. 2478-2493 ◽  
Author(s):  
Xiaoli Li ◽  
Huimin Zhang ◽  
Qin Ai ◽  
Gang Liang ◽  
Diqiu Yu
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Iron Homeostasis ◽  
Bhlh Transcription Factors

scholarly journals Annotation and Molecular Characterisation of the TaIRO3 and TaHRZ Iron Homeostasis Genes in Bread Wheat (Triticum aestivum L.)

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 653
Author(s):  
Oscar Carey-Fung ◽  
Jesse T. Beasley ◽  
Alexander A. T. Johnson
Keyword(s):  
Triticum Aestivum ◽  
Bread Wheat ◽  
Iron Homeostasis ◽  
Zinc Finger Protein ◽  
Expression Profiles ◽  
Diploid Species ◽  
Triticum Aestivum L ◽  
Fe Deficiency ◽  
Pcr Analysis ◽  
Fe Homeostasis

Effective maintenance of plant iron (Fe) homoeostasis relies on a network of transcription factors (TFs) that respond to environmental conditions and regulate Fe uptake, translocation, and storage. The iron-related transcription factor 3 (IRO3), as well as haemerythrin motif-containing really interesting new gene (RING) protein and zinc finger protein (HRZ), are major regulators of Fe homeostasis in diploid species like Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa L.), but remain uncharacterised in hexaploid bread wheat (Triticum aestivum L.). In this study, we have identified, annotated, and characterised three TaIRO3 homoeologs and six TaHRZ1 and TaHRZ2 homoeologs in the bread wheat genome. Protein analysis revealed that TaIRO3 and TaHRZ proteins contain functionally conserved domains for DNA-binding, dimerisation, Fe binding, or polyubiquitination, and phylogenetic analysis revealed clustering of TaIRO3 and TaHRZ proteins with other monocot IRO3 and HRZ proteins, respectively. Quantitative reverse-transcription PCR analysis revealed that all TaIRO3 and TaHRZ homoeologs have unique tissue expression profiles and are upregulated in shoot tissues in response to Fe deficiency. After 24 h of Fe deficiency, the expression of TaHRZ homoeologs was upregulated, while the expression of TaIRO3 homoeologs was unchanged, suggesting that TaHRZ functions upstream of TaIRO3 in the wheat Fe homeostasis TF network.

scholarly journals Transcriptomics Reveals Fast Changes in Salicylate and Jasmonate Signaling Pathways in Shoots of Carbonate-Tolerant Arabidopsis thaliana under Bicarbonate Exposure

2021 ◽  
Vol 22 (3) ◽  
pp. 1226
Author(s):  
Laura Pérez-Martín ◽  
Silvia Busoms ◽  
Roser Tolrà ◽  
Charlotte Poschenrieder
Keyword(s):  
Cell Cycle ◽  
Arabidopsis Thaliana ◽  
Iron Homeostasis ◽  
Calcareous Soils ◽  
Fe Deficiency ◽  
Starch Degradation ◽  
Sulfur Starvation ◽  
Aerial Parts ◽  
Key Factor ◽  
Alkaline Conditions

High bicarbonate concentrations of calcareous soils with high pH can affect crop performance due to different constraints. Among these, Fe deficiency has mostly been studied. The ability to mobilize sparingly soluble Fe is a key factor for tolerance. Here, a comparative transcriptomic analysis was performed with two naturally selected Arabidopsis thaliana demes, the carbonate-tolerant A1(c+) and the sensitive T6(c−). Analyses of plants exposed to either pH stress alone (pH 5.9 vs. pH 8.3) or to alkalinity caused by 10 mM NaHCO3 (pH 8.3) confirmed better growth and nutrient homeostasis of A1(c+) under alkaline conditions. RNA-sequencing (RNA-seq) revealed that bicarbonate quickly (3 h) induced Fe deficiency-related genes in T6(c−) leaves. Contrastingly, in A1(c+), initial changes concerned receptor-like proteins (RLP), jasmonate (JA) and salicylate (SA) pathways, methionine-derived glucosinolates (GS), sulfur starvation, starch degradation, and cell cycle. Our results suggest that leaves of carbonate-tolerant plants do not sense iron deficiency as fast as sensitive ones. This is in line with a more efficient Fe translocation to aerial parts. In A1(c+) leaves, the activation of other genes related to stress perception, signal transduction, GS, sulfur acquisition, and cell cycle precedes the induction of iron homeostasis mechanisms yielding an efficient response to bicarbonate stress.

scholarly journals NUCLEAR FACTOR Y, Subunit C (NF-YC) Transcription Factors Are Positive Regulators of Photomorphogenesis in Arabidopsis thaliana

PLoS Genetics ◽  
2016 ◽  
Vol 12 (9) ◽  
pp. e1006333 ◽  
Author(s):  
Zachary A. Myers ◽  
Roderick W. Kumimoto ◽  
Chamindika L. Siriwardana ◽  
Krystal K. Gayler ◽  
Jan R. Risinger ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Nuclear Factor ◽  
Subunit C ◽  
Nuclear Factor Y ◽  
Positive Regulators

scholarly journals NUCLEAR FACTOR Y, subunit C (NF-YC) transcription factors are positive regulators of photomorphogenesis in Arabidopsis thaliana

2016 ◽  
Author(s):  
Zachary A. Myers ◽  
Roderick W. Kumimoto ◽  
Chamindika L. Siriwardana ◽  
Krystal K. Gayler ◽  
Jan R. Risinger ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Leucine Zipper ◽  
Complete Picture ◽  
Nuclear Factor ◽  
Light Perception ◽  
Basic Leucine Zipper ◽  
Nuclear Factor Y ◽  
Positive Regulators ◽  
Early Seedling

AbstractRecent reports suggested that NF-Y transcription factors are positive regulators of skotomorphogenesis in Arabidopsis thaliana. Three NF-YC genes (NF-YC3, NF-YC4, and NF-YC9) are known to have overlapping functions in photoperiod dependent flowering and previous studies demonstrated that they interact with basic leucine zipper (bZIP) transcription factors. This included ELONGATED HYPOCOTYL 5 (HY5), which has well-demonstrated roles in photomorphogenesis. Similar to hy5 mutants, we report that nf-yc3 nf-yc4 nf-yc9 triple mutants failed to inhibit hypocotyl elongation in all tested light wavelengths. Surprisingly, nf-yc3 nf-yc4 nf-yc9 hy5 mutants had synergistic defects in light perception, suggesting that NF-Ys represent a parallel light signaling pathway. As with other photomorphogenic transcription factors, nf-yc3 nf-yc4 nf-yc9 triple mutants also partially suppress the short hypocotyl and dwarf rosette phenotypes of CONSTITUTIVE PHOTOMORPHOGENIC 1 (cop1) mutants. Thus, our data strongly suggest that NF-Y transcription factors have important roles as positive regulators of photomorphogenesis, and in conjunction with other recent reports implies that the NF-Y are multifaceted regulators of early seedling development.Author SummaryLight perception is critically important for the fitness of plants in both natural and agricultural settings. Plants not only use light for photosynthesis, but also as a cue for proper development. As a seedling emerges from soil it must determine the light environment and adopt an appropriate growth habit. When blue and red wavelengths are the dominant sources of light, plants will undergo photomorphogenesis. Photomorphogenesis describes a number of developmental responses initiated by light in a seedling, and includes shortened stems and establishing the ability to photosynthesize. The genes regulating photomorphogenesis have been studied extensively, but a complete picture remains elusive. Here we describe the finding that NUCLEAR FACTOR-Y (NF-Y) genes are positive regulators of photomorphogenesis - i.e., in plants where NF-Y genes are mutated, they display some characteristics of dark grown plants, even though they are in the light. Our data suggests that the roles of NF-Y genes in light perception do not fit in easily with those of other described pathways. Thus, studying these genes promises to help develop a more complete picture of how light drives plant development.

scholarly journals Functional Characterization Of The VAC14 Self-Interaction Domain

2021 ◽  
Author(s):  
Tamadher A. Alghamdi
Keyword(s):  
Functional Characterization ◽  
Regulatory Protein ◽  
Adaptor Protein ◽  
Interaction Domain ◽  
Lipid Kinase ◽  
Lipid Phosphatase ◽  
C Terminus ◽  
Regulatory Complex ◽  
Steady State Levels ◽  
And Function

PtdIns(3,5)P2 is a low-abundance signaling lipid present at < 0.1 % of total PtdIns lipids in yeasts and mammals. Reduced levels of PtdIns(3,5)P2 contributes to neurodegenerative disorders in humans and vacuolar defects in yeasts. Steady-state levels of PtdIns(3,5)P2 are dependent on both its rate of synthesis and turnover. In yeast, PtdIns(3,5)P2 is produced on the vacuole membrane by phosphorylation of PtdIns(3)P at the 5 position of its inositol ring by the Fab1 lipid kinase. Cells lacking Fab1 make no PtdIns(3,5)P2 and exhibit defects in vacuole morphology and function. The lipid phosphatase Fig4 counteracts Fab1 activity by turnover of PtdIns(3,5)P2 into PtdIns(3)P. Vac14 is a regulatory protein implicated in the synthesis and turnover of PtdIns(3,5)P2. It acts as an adaptor protein that controls both of Fab1 and Fig4 proteins. In addition, Vac14 exists as a multimer that allows for self-interaction. However, multimerization state of Vac14 as well as the domain responsible for self-interaction remained unknown. This study aimed to identify the self-interaction domain to elucidate its role in the assembly of the regulatory complex of PtdIns(3,5)P2. The observations seen in this study suggested that Vac14 self-interacts via multiple conserved motifs in the C-terminus, which are crucial for interaction with Fab1 and Fig4, and the normal morphology of yeast vacuoles.

scholarly journals Iron deficiency induced changes in Fe homeostasis and 14-3-3 interactomics of Arabidopsis thaliana

2021 ◽  
Author(s):  
Jing Gao ◽  
Paula J. M. Kleeff ◽  
Ka Wan Li ◽  
Albertus H. Boer
Keyword(s):  
Arabidopsis Thaliana ◽  
Sufficient Conditions ◽  
Tca Cycle ◽  
Fe Deficiency ◽  
Functional Aspects ◽  
Clear Explanation ◽  
Fe Uptake ◽  
Physiological Analysis ◽  
Fe Homeostasis ◽  
Induced Changes

Abstract Members of 14-3-3 protein family are involved in the proper operation of Fe acquisition mechanisms at physiological and gene expression levels in Arabidopsis thaliana. To more directly and effectively observe whether members of 14-3-3 non-epsilon group have a function in Fe-deficiency adaptation, three higher order quadruple KOs, kappa/lambda/phi/chi (klpc), kappa/lambda/upsilon/nu(klun), and upsilon/nu/phi/chi (unpc) were generated and applied for physiological analysis in this study. The mutant plants that combine kl with un (klun) or kl with pc (klpc) mutations showed a better Fe uptake than Wt plants at low medium Fe, while this phenotype was absent in unpc mutant. The higher Fe uptake by klun correlated with a higher Fe-deficiency induced expression of selected Fe-related genes. The dynamics of 14-3-3-client interactions analysis showed that a subset of 27 proteins differentially interacted with 14-3-3 in roots caused by Fe deficiency. Many of these Fe responsive proteins have a role in glycolysis and TCA cycle, the FoF1-synthase and in the cysteine/methionine synthesis. Also, the 14-3-3 interactome of the klun roots showed significant differences with that of Wt roots under Fe sufficient conditions, where most of these differential binding proteins showed enhanced binding in the klun mutant. Nevertheless, a clear explanation for the observed phenotypes awaits a more detailed analysis of the functional aspects of 14-3-3 binding to the target proteins identified in this study.

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