Comparison of iron acquisition from Fe–pyoverdine by strategy I and strategy II plants

Botany ◽  
2011 ◽  
Vol 89 (10) ◽  
pp. 731-735 ◽  
Author(s):  
Matt Shirley ◽  
Laure Avoscan ◽  
Eric Bernaud ◽  
Gérard Vansuyt ◽  
Philippe Lemanceau
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Species ◽  
Iron Uptake ◽  
Iron Acquisition ◽  
Iron Status ◽  
Iron Nutrition ◽  
Perennial Species ◽  
Major Class ◽  
Graminaceous Plants ◽  
Strategy I

Iron is an essential micronutrient for plants and associated microorganisms. However, the bioavailability of iron in cultivated soils is low. Plants and microorganisms have thus evolved active strategies of iron uptake. Two different iron uptake strategies have been described in dicotyledonous and monocotyledonous graminaceous species. In bacteria, this strategy relies on the synthesis of siderophores. Pyoverdines, a major class of siderophores produced by fluorescent pseudomonads, were previously shown to promote iron nutrition of the dicotyledonous species Arabidopsis thaliana L. (Heynh.), whereas contradictory reports were made on the contribution of those siderophores to the nutrition of graminaceous annuals. Furthermore, no information has so far been available on graminaceous perennials. Here, the contribution of purified pyoverdine of Pseudomonas fluorescens C7R12 to the iron nutrition of two annual and perennial graminaceous plants was assessed and compared with that of two dicotyledonous plant species. Fe–Pyoverdine promoted the iron status of all plant species tested. With the exception of wheat, this promotion was more dramatic in graminaceous species than in dicotyledonous species and was the highest in fescue, a perennial species. The incorporation of 15N-labeled pyoverdine was consistent with the effect on the iron status of the plants tested.

scholarly journals Iron Acquisition from Fe-Pyoverdine by Arabidopsis thaliana

2007 ◽  
Vol 20 (4) ◽  
pp. 441-447 ◽  
Author(s):  
Gérard Vansuyt ◽  
Agnès Robin ◽  
Jean-François Briat ◽  
Catherine Curie ◽  
Philippe Lemanceau
Keyword(s):  
Arabidopsis Thaliana ◽  
Iron Content ◽  
Reductase Activity ◽  
Iron Acquisition ◽  
Iron Nutrition ◽  
Enzyme Linked Immunosorbent Assay ◽  
Wild Type ◽  
In Planta ◽  
Chlorophyll Contents ◽  
The Impact

Taking into account the strong iron competition in the rhizosphere and the high affinity of pyoverdines for Fe(III), these molecules are expected to interfere with the iron nutrition of plants, as they do with rhizospheric microbes. The impact of Fe-pyoverdine on iron content of Arabidopsis thaliana was compared with that of Fe-EDTA. Iron chelated to pyoverdine was incorporated in a more efficient way than when chelated to EDTA, leading to increased plant growth of the wild type. A transgenic line of A. thaliana overexpressing ferritin showed a higher iron content than the wild type when supplemented with Fe-EDTA but a lower iron content when supplemented with Fe-pyoverdine despite its increased reductase activity, suggesting that this activity was not involved in the iron uptake from pyoverdine. A mutant knockout iron transporter IRT1 showed lower iron and chlorophyll contents when supplemented with Fe-EDTA than the wild type but not when supplemented with Fe-pyoverdine, indicating that, in contrast to iron from EDTA, iron from pyoverdine was not incorporated through the IRT1 transporter. Altogether these data suggest that iron from Fe-pyoverdine was not incorporated in planta through the strategy I, which is based on reductase activity and IRT1 transporter. This is supported by the presence of pyoverdine in planta as shown by enzyme-linked immunosorbent assay and by tracing 15N of 15N-pyoverdine.

scholarly journals Uptake of Fe-fraxetin complexes, an IRT1 independent strategy for iron acquisition in Arabidopsis thaliana.

2021 ◽  
Author(s):  
Kevin ROBE ◽  
max STASSEN ◽  
joseph CHAMIEH ◽  
philippe GONZALEZ ◽  
sonia HEM ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Iron Uptake ◽  
Iron Acquisition ◽  
Grass Species ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Fe Acquisition ◽  
Dependent Mechanism ◽  
Exogenous Supply

Iron (Fe) is a micronutrient essential for plant growth and development. Iron uptake in alkaline soil is a challenge for most plants. In this study, we investigated the role of the catechol coumarins fraxetin and esculetin in plant Fe acquisition and their Fe chelating properties. Mass spectrometry and capillary electrophoresis were used to characterize Fe-coumarin complexes. To understand the role of these complexes, genetic, molecular and biochemical approaches were deployed. We demonstrated that catechol coumarins are taken up by Arabidopsis thaliana root via an ATP dependent mechanism and that plants defective in IRT1 activity (the main high affinity Fe importer) or bHLH121 (a key regulator of Fe deficiency responses) can be complemented by exogenous supply of fraxetin and to a lesser extent of esculetin. We also showed that Fe and fraxetin can form stable complexes at neutral to alkaline pH that can be taken up by the plant. Overall, these results indicate that at high pH, fraxetin can improve Fe nutrition by directly transporting Fe(III) into the root, circumventing the FRO2/IRT1 system, in a similar way as phytosiderophores do in grasses. This strategy may explain how non-grass species can thrive in alkaline soils.

scholarly journals AtbHLH29 of Arabidopsis thaliana is a functional ortholog of tomato FER involved in controlling iron acquisition in strategy I plants

Cell Research ◽  
2005 ◽  
Vol 15 (8) ◽  
pp. 613-621 ◽  
Author(s):  
You Xi YUAN ◽  
Juan ZHANG ◽  
Dao Wen WANG ◽  
Hong Qing LING
Keyword(s):  
Arabidopsis Thaliana ◽  
Iron Acquisition ◽  
Strategy I

scholarly journals Importance of the Rhizosphere Microbiota in Iron Biofortification of Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Tristan Lurthy ◽  
Barbara Pivato ◽  
Philippe Lemanceau ◽  
Sylvie Mazurier
Keyword(s):  
Iron Content ◽  
Iron Uptake ◽  
Plant Traits ◽  
Iron Status ◽  
Holistic Approach ◽  
Human Nutrition ◽  
Iron Nutrition ◽  
Nutrition And Health ◽  
Hidden Hunger ◽  
Microbe Interactions

Increasing the iron content of plant products and iron assimilability represents a major issue for human nutrition and health. This is also a major challenge because iron is not readily available for plants in most cultivated soils despite its abundance in the Earth’s crust. Iron biofortification is defined as the enhancement of the iron content in edible parts of plants. This biofortification aims to reach the objectives defined by world organizations for human nutrition and health while being environment friendly. A series of options has been proposed to enhance plant iron uptake and fight against hidden hunger, but they all show limitations. The present review addresses the potential of soil microorganisms to promote plant iron nutrition. Increasing knowledge on the plant microbiota and plant-microbe interactions related to the iron dynamics has highlighted a considerable contribution of microorganisms to plant iron uptake and homeostasis. The present overview of the state of the art sheds light on plant iron uptake and homeostasis, and on the contribution of plant-microorganism (plant-microbe and plant-plant-microbe) interactions to plant nutritition. It highlights the effects of microorganisms on the plant iron status and on the co-occurring mechanisms, and shows how this knowledge may be valued through genetic and agronomic approaches. We propose a change of paradigm based on a more holistic approach gathering plant and microbial traits mediating iron uptake. Then, we present the possible applications in plant breeding, based on plant traits mediating plant-microbe interactions involved in plant iron uptake and physiology.

scholarly journals The iron deficiency response in Arabidopsis thaliana requires the phosphorylated transcription factor URI

2019 ◽  
Vol 116 (50) ◽  
pp. 24933-24942 ◽  
Author(s):  
Sun A. Kim ◽  
Ian S. LaCroix ◽  
Scott A. Gerber ◽  
Mary Lou Guerinot
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Iron Deficiency ◽  
Iron Uptake ◽  
Iron Status ◽  
Bhlh Transcription Factor ◽  
Excess Iron ◽  
Phosphorylated Form

Iron is an essential nutrient for plants, but excess iron is toxic due to its catalytic role in the formation of hydroxyl radicals. Thus, iron uptake is highly regulated and induced only under iron deficiency. The mechanisms of iron uptake in roots are well characterized, but less is known about how plants perceive iron deficiency. We show that a basic helix–loop–helix (bHLH) transcription factor Upstream Regulator of IRT1 (URI) acts as an essential part of the iron deficiency signaling pathway in Arabidopsis thaliana. The uri mutant is defective in inducing Iron-Regulated Transporter1 (IRT1) and Ferric Reduction Oxidase2 (FRO2) and their transcriptional regulators FER-like iron deficiency-induced transcription factor (FIT) and bHLH38/39/100/101 in response to iron deficiency. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) reveals direct binding of URI to promoters of many iron-regulated genes, including bHLH38/39/100/101 but not FIT. While URI transcript and protein are expressed regardless of iron status, a phosphorylated form of URI only accumulates under iron deficiency. Phosphorylated URI is subject to proteasome-dependent degradation during iron resupply, and turnover of phosphorylated URI is dependent on the E3 ligase BTS. The subgroup IVc bHLH transcription factors, which have previously been shown to regulate bHLH38/39/100/101, coimmunoprecipitate with URI mainly under Fe-deficient conditions, suggesting that it is the phosphorylated form of URI that is capable of forming heterodimers in vivo. We propose that the phosphorylated form of URI accumulates under Fe deficiency, forms heterodimers with subgroup IVc proteins, and induces transcription of bHLH38/39/100/101. These transcription factors in turn heterodimerize with FIT and drive the transcription of IRT1 and FRO2 to increase Fe uptake.

scholarly journals CBIO-10. REDUCED IRON EXPORT FUNCTIONS IN A CELL INTRINSIC MANNER TO DRIVE GLIOBLASTOMA GROWTH

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii17-ii17
Author(s):  
Katie Troike ◽  
Erin Mulkearns-Hubert ◽  
Daniel Silver ◽  
James Connor ◽  
Justin Lathia
Keyword(s):  
Tumor Cells ◽  
Iron Uptake ◽  
Iron Homeostasis ◽  
Iron Status ◽  
Tumor Grade ◽  
Hfe Gene ◽  
Iron Release ◽  
Female Patients ◽  
Cellular Iron

Abstract Glioblastoma (GBM), the most common primary malignant brain tumor in adults, is characterized by invasive growth and poor prognosis. Iron is a critical regulator of many cellular processes, and GBM tumor cells have been shown to modulate expression of iron-associated proteins to enhance iron uptake from the surrounding microenvironment, driving tumor initiation and growth. While iron uptake has been the central focus of previous investigations, additional mechanisms of iron regulation, such as compensatory iron efflux, have not been explored in the context of GBM. The hemochromatosis (HFE) gene encodes a transmembrane glycoprotein that aids in iron homeostasis by limiting cellular iron release, resulting in a sequestration phenotype. We find that HFE is upregulated in GBM tumors compared to non-tumor brain and that expression of HFE increases with tumor grade. Furthermore, HFE mRNA expression is associated with significantly reduced survival specifically in female patients with GBM. Based on these findings, we hypothesize that GBM tumor cells upregulate HFE expression to augment cellular iron loading and drive proliferation, ultimately leading to reduced survival of female patients. To test this hypothesis, we generated Hfe knockdown and overexpressing mouse glioma cell lines. We observed significant alterations in the expression of several iron handling genes with Hfe knockdown or overexpression, suggesting global disruption of iron homeostasis. Additionally, we show that knockdown of Hfe in these cells increases apoptosis and leads to a significant impairment of tumor growth in vivo. These findings support the hypothesis that Hfe is a critical regulator of cellular iron status and contributes to tumor aggression. Future work will include further exploration of the mechanisms that contribute to these phenotypes as well as interactions with the tumor microenvironment. Elucidating the mechanisms by which iron effulx contributes to GBM may inform the development of next-generation targeted therapies.

scholarly journals Bacterial effector targeting of a plant iron sensor facilitates iron acquisition and pathogen colonization

2021 ◽  
Author(s):  
Yingying Xing ◽  
Ning Xu ◽  
Deepak D Bhandari ◽  
Dmitry Lapin ◽  
Xinhua Sun ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Iron Uptake ◽  
Iron Acquisition ◽  
Iron Accumulation ◽  
Regulatory Proteins ◽  
Mineral Nutrient ◽  
Effector Protein ◽  
Iron Regulatory Proteins ◽  
Protein Levels ◽  
Pathogen Colonization

Abstract Acquisition of nutrients from different species is necessary for pathogen colonization. Iron is an essential mineral nutrient for nearly all organisms, but little is known about how pathogens manipulate plant hosts to acquire iron. Here, we report that AvrRps4, an effector protein delivered by Pseudomonas syringae bacteria to plants, interacts with and targets the plant iron sensor protein BRUTUS (BTS) to facilitate iron uptake and pathogen proliferation in Arabidopsis thaliana. Infection of rps4 and eds1 by P. syringae pv. tomato (Pst) DC3000 expressing AvrRps4 resulted in iron accumulation, especially in the plant apoplast. AvrRps4 alleviates BTS-mediated degradation of bHLH115 and ILR3(IAA-Leucine resistant 3), two iron regulatory proteins. In addition, BTS is important for accumulating immune proteins Enhanced Disease Susceptibility1 (EDS1) at both the transcriptional and protein levels upon Pst (avrRps4) infections. Our findings suggest that AvrRps4 targets BTS to facilitate iron accumulation and BTS contributes to RPS4/EDS1-mediated immune responses.

scholarly journals The potential effect of iron defortification on iron-deficiency anaemia in the US population

2007 ◽  
Vol 10 (11) ◽  
pp. 1266-1273 ◽  
Author(s):  
Min Tao ◽  
David L Pelletier ◽  
Dennis D Miller
Keyword(s):  
Iron Deficiency ◽  
Iron Deficiency Anaemia ◽  
Iron Status ◽  
Potential Effect ◽  
Reproductive Age ◽  
Iron Nutrition ◽  
Deficiency Anaemia ◽  
Adult Men ◽  
The Us ◽  
The Usa

AbstractObjectiveTo quantify the potential effect of iron defortification in the USA on iron-deficiency anaemia (IDA).MethodsMonte Carlo models were built to simulate iron nutrition in the US population. A hypothetical cohort of 15 000 persons from the general population was used in 15-year simulations to compare the prevalence of IDA with and without fortification.ResultsWith iron fortification, the prevalence of IDA was 2.4% for children aged 3–5 years, 5.4% for women aged 20–49 years, and 0.14% for men aged 20–49 years. The corresponding IDA estimates under iron defortification were 4.5%, 8.2% and 0.46%, respectively. Defortification had little effect on the distribution of iron indicators at or above the 50th percentile within each of these three groups and little effect on the distributions of iron indicators among adult men.ConclusionIron defortification is likely to increase IDA among children and women of reproductive age, but is not likely to have meaningful effects on the iron status of men or the majority of women and children.

scholarly journals Genes Essential to Iron Transport in the Cyanobacterium Synechocystis sp. Strain PCC 6803

2001 ◽  
Vol 183 (9) ◽  
pp. 2779-2784 ◽  
Author(s):  
Hirokazu Katoh ◽  
Natsu Hagino ◽  
Arthur R. Grossman ◽  
Teruo Ogawa
Keyword(s):  
Iron Uptake ◽  
Iron Transport ◽  
Ferric Iron ◽  
Iron Acquisition ◽  
Complete Medium ◽  
Iron Starvation ◽  
Transporter Family ◽  
Genes Encoding ◽  
In Cells ◽  
Pcc 6803

ABSTRACT Genes encoding polypeptides of an ATP binding cassette (ABC)-type ferric iron transporter that plays a major role in iron acquisition inSynechocystis sp. strain PCC 6803 were identified. These genes are slr1295, slr0513, slr0327, and recently reportedsll1878 (Katoh et al., J. Bacteriol. 182:6523–6524, 2000) and were designated futA1, futA2, futB, andfutC, respectively, for their involvement in ferric iron uptake. Inactivation of these genes individually or futA1and futA2 together greatly reduced the activity of ferric iron uptake in cells grown in complete medium or iron-deprived medium. All the fut genes are expressed in cells grown in complete medium, and expression was enhanced by iron starvation. ThefutA1 and futA2 genes appear to encode periplasmic proteins that play a redundant role in iron binding. The deduced products of futB and futC genes contain nucleotide-binding motifs and belong to the ABC transporter family of inner-membrane-bound and membrane-associated proteins, respectively. These results and sequence similarities among the four genes suggest that the Fut system is related to the Sfu/Fbp family of iron transporters. Inactivation of slr1392, a homologue offeoB in Escherichia coli, greatly reduced the activity of ferrous iron transport. This system is induced by intracellular low iron concentrations that are achieved in cells exposed to iron-free medium or in the fut-less mutants grown in complete medium.

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