Transcriptional and physiological changes in relation to Fe uptake under conditions of Fe-deficiency and Cd-toxicity in roots of Vigna radiata L.

2014 ◽  
Vol 127 (6) ◽  
pp. 731-742 ◽  
Author(s):  
Sowbiya Muneer ◽  
Byoung Ryong Jeong ◽  
Tae-Hwan Kim ◽  
Jeong Hyun Lee ◽  
Prabhakaran Soundararajan
Keyword(s):  
Vigna Radiata ◽  
Fe Deficiency ◽  
Physiological Changes ◽  
Cd Toxicity ◽  
Fe Uptake

scholarly journals Iron absorption in hepcidin1 knockout mice

2011 ◽  
Vol 105 (11) ◽  
pp. 1583-1591 ◽  
Author(s):  
Patarabutr Masaratana ◽  
Abas H. Laftah ◽  
Gladys O. Latunde-Dada ◽  
Sophie Vaulont ◽  
Robert J. Simpson ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Iron Absorption ◽  
Fe Deficiency ◽  
Acute Effects ◽  
Regulatory Peptide ◽  
Fe Uptake

Hepcidin, the Fe-regulatory peptide, has been shown to inhibit Fe absorption and reticuloendothelial Fe recycling. The present study was conducted to explore the mechanism of in vivo Fe regulation through genetic disruption of hepcidin1 and acute effects of hepcidin treatment in hepcidin1 knockout (Hepc1− / − ) and heterozygous mice. Hepcidin1 disruption resulted in significantly increased intestinal Fe uptake. Hepcidin injection inhibited Fe absorption in both genotypes, but the effects were more evident in the knockout mice. Hepcidin administration was also associated with decreased membrane localisation of ferroportin in the duodenum, liver and, most significantly, in the spleen of Hepc1− / −  mice. Hypoferraemia was induced in heterozygous mice by hepcidin treatment, but not in Hepc1− / −  mice, 4 h after injection. Interestingly, Fe absorption and serum Fe levels in Hepc1− / −  and heterozygous mice fed a low-Fe diet were not affected by hepcidin injection. The present study demonstrates that hepcidin deficiency causes increased Fe absorption. The effects of hepcidin were abolished by dietary Fe deficiency, indicating that the response to hepcidin may be influenced by dietary Fe level or Fe status.

scholarly journals MNB1 gene is involved in regulating the iron-deficiency stress response in Arabidopsis thaliana

2021 ◽  
Author(s):  
Hui Song ◽  
Feng Chen ◽  
Xi Wu ◽  
Min Hu ◽  
Qingliu Geng ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Arabidopsis Thaliana ◽  
Normal Growth ◽  
Developmental Changes ◽  
Fe Deficiency ◽  
Oxygen Species ◽  
Mineral Element ◽  
Wild Type ◽  
Transcription Level ◽  
Fe Uptake

Abstract Abstract Iron (Fe) is an indispensable mineral element for normal growth of plants. Fe deficiency induces a complex series of responses in plants, involving physiological and developmental changes, to increase Fe uptake from soil. However, the molecular mechanism involved in plant Fe-deficiency is not well understood. Here, we found that the MNB1 gene is involved in modulating Fe-deficiency response in Arabidopsis thaliana . The expression of MNB1 was inhabited by Fe-deficiency stress. Knockout of MNB1 led to enhanced Fe accumulation and tolerance, whereas the MNB1-overexpressing plants were sensitive to Fe-deficiency stress. Lower H 2 O 2 concentrations in mnb1 mutant plants were examined under Fe deficiency circumstances compared to wild-type. On the contray, higher H 2 O 2 concentrations were found in MNB1-overexpressing plants, which was adversely linked with malondialdehyde (MDA) concentrations. Furthermore, in mnb1 mutants, the transcription level of the Fe-uptake and translocation genes, FIT , IRT1 , FRO2 , Z IF , FRD3 , NAS4 , PYE and MYB72 , were considerably elevated during Fe-deficiency stress, resulting in higher Fe accumulation. Together, our findings show that the MNB1 gene negatively controls the Fe-deficiency response in Arabidopsis via modulating reactive oxygen species (ROS) levels and the ROS-mediated signaling pathway, thereby affecting the expression of Fe-uptake and translocation genes.

Physiological Changes and Yield Responses of Greengram (Vigna radiata L.)Under Elevated Temperature Stress

2019 ◽  
Vol 106 (4-6) ◽  
Author(s):  
B. Rakavi ◽  
N. Sritharan ◽  
A. Senthil ◽  
S. Kokilavani ◽  
S. Pannerselvam ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Temperature Stress ◽  
Vigna Radiata ◽  
Physiological Changes ◽  
Yield Responses

scholarly journals FIT, a regulatory hub for iron deficiency and stress signaling in roots, and FIT-dependent and -independent gene signatures

2020 ◽  
Vol 71 (5) ◽  
pp. 1694-1705 ◽  
Author(s):  
Birte Schwarz ◽  
Petra Bauer
Keyword(s):  
Transcription Factor ◽  
Protein Interactions ◽  
Fe Deficiency ◽  
Bhlh Transcription Factor ◽  
Root Cells ◽  
Gene Signatures ◽  
Helix Loop Helix ◽  
Independent Gene ◽  
Fe Uptake ◽  
Fe Acquisition

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.

scholarly journals Studies on the control of iron uptake by rabbit small intestine

1982 ◽  
Vol 47 (2) ◽  
pp. 251-258 ◽  
Author(s):  
T. M. Cox ◽  
M. W. O'Donnell
Keyword(s):  
Regional Distribution ◽  
Maximum Velocity ◽  
Whole Body ◽  
Fe Deficiency ◽  
Distal Intestine ◽  
Body Retention ◽  
Fe Uptake ◽  
Active Transport Process

1. Whole-body retention in vivo and uptake of 59Fe-labelled ascorbate and nitrilotriacetate chelates by intestinal slices in vitro were determined in groups of normal control rabbits and rabbits with experimentally-induced Fe deficiency.2. Over-all absorption as measured by retention of doses of either chelate was greatly increased in conditions of Fe deficiency.3. Intestinal Fe uptake in vitro was inhibited up to 77% in the presence of 2,4-dinitrophenol and sodium fluoride. Initial rates showed saturation within the concentration range 18–450 μmol/l, suggesting that uptake was brought about by an active transport process.4. When studied at chelate concentrations of 450 μmol/l, significant regional differences in uptake rates were observed. Uptake in duodenal slices was increased when compared with slices from jejunum and ileum.5. Fe uptake from ferric and ferrous chelates was greatly enhanced in Fe deficiency. This was chiefly due to increases in uptake by slices from the duodenum, but uptake into slices of distal intestine was also stimulated.6. Kinetic analysis of Fe uptake by duodenal slices from animals rendered Fe deficient by diet or repeated bleeding indicated in both groups an increased apparent maximum velocity (Vmax) for influx of Fe without significant changes in apparent affinity for Fe.7. The experiments provide further insight into the nature and regional distribution of transport of Fe into the intestine and suggest, in the rabbit, that important control of Fe absorption may be exerted by an active process operating at this initial entry step.

scholarly journals Outer Membrane Iron Uptake Pathways in the Model Cyanobacterium Synechocystis sp. Strain PCC 6803

2018 ◽  
Vol 84 (19) ◽  
Author(s):  
Guo-Wei Qiu ◽  
Wen-Jing Lou ◽  
Chuan-Yu Sun ◽  
Nina Yang ◽  
Zheng-Ke Li ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Uptake Rate ◽  
Passive Diffusion ◽  
Aquatic Systems ◽  
Fe Deficiency ◽  
Wild Type ◽  
Content Type ◽  
Fe Uptake ◽  
Fe Acquisition ◽  
Pcc 6803

ABSTRACT Cyanobacteria are foundational drivers of global nutrient cycling, with high intracellular iron (Fe) requirements. Fe is found at extremely low concentrations in aquatic systems, however, and the ways in which cyanobacteria take up Fe are largely unknown, especially the initial step in Fe transport across the outer membrane. Here, we identified one TonB protein and four TonB-dependent transporters (TBDTs) of the energy-requiring Fe acquisition system and six porins of the passive diffusion Fe uptake system in the model cyanobacterium Synechocystis sp. strain PCC 6803. The results experimentally demonstrated that TBDTs not only participated in organic ferri-siderophore uptake but also in inorganic free Fe (Fe′) acquisition. 55Fe uptake rate measurements showed that a TBDT quadruple mutant acquired Fe at a lower rate than the wild type and lost nearly all ability to take up ferri-siderophores, indicating that TBDTs are critical for siderophore uptake. However, the mutant retained the ability to take up Fe′ at 42% of the wild-type Fe′ uptake rate, suggesting additional pathways of Fe′ acquisition besides TBDTs, likely by porins. Mutations in four of the six porin-encoding genes produced a low-Fe-sensitive phenotype, while a mutation in all six genes was lethal to cell survival. These diverse outer membrane Fe uptake pathways reflect cyanobacterial evolution and adaptation under a range of Fe regimes across aquatic systems. IMPORTANCE Cyanobacteria are globally important primary producers and contribute about 25% of global CO2 fixation. Low Fe bioavailability in surface waters is thought to limit the primary productivity in as much as 40% of the global ocean. The Fe acquisition strategies that cyanobacteria have evolved to overcome Fe deficiency remain poorly characterized. We experimentally characterized the key players and the cooperative work mode of two Fe uptake pathways, including an active uptake pathway and a passive diffusion pathway in the model cyanobacterium Synechocystis sp. PCC 6803. Our finding proved that cyanobacteria use ferri-siderophore transporters to take up Fe′, and they shed light on the adaptive mechanisms of cyanobacteria to cope with widespread Fe deficiency across aquatic environments.

Ethylene involvement in the regulation of Fe-deficiency stress responses by Strategy I plants

2004 ◽  
Vol 31 (4) ◽  
pp. 315 ◽  
Author(s):  
Francisco J. Romera ◽  
Esteban Alcántara
Keyword(s):  
Stress Responses ◽  
Higher Plants ◽  
Root Hairs ◽  
Transfer Cells ◽  
Fe Deficiency ◽  
Physiological Changes ◽  
Strategy I

Plants have developed different mechanisms for the acquisition of iron (Fe). Depending on the mechanisms, plants are classified into two groups: Strategy I and Strategy II. Strategy I plants include all higher plants except the Gramineae, while Strategy II plants comprise the Gramineae. When plants suffer from Fe-deficiency, they develop several morphological and physiological changes in their roots, known as Fe-deficiency stress responses, which disappear when the plants acquire enough Fe. In Strategy I plants, these changes include subapical swelling with abundant root hairs, transfer cells, acidification of the rhizosphere, enhancement of the capacity to reduce Fe3+ to Fe2+, enhancement of the capacity for Fe2+ uptake, release of flavins, and others. The regulation of these responses is not fully understood but in recent years there has been evidence suggesting the involvement of ethylene in this process. This review summarises different results that support a role for this hormone in the regulation of Fe-deficiency stress responses by Strategy I plants.

scholarly journals A Novel Citrus Rootstock Tolerant to Iron Deficiency in Calcareous Soil

2016 ◽  
Vol 141 (2) ◽  
pp. 112-118 ◽  
Author(s):  
Lina Fu ◽  
Lijun Chai ◽  
Dekuan Ding ◽  
Zhiyong Pan ◽  
Shu’ang Peng
Keyword(s):  
Cell Wall ◽  
Calcareous Soil ◽  
Chlorophyll Concentration ◽  
Shaanxi Province ◽  
Fe Deficiency ◽  
Soil Conditions ◽  
Trifoliate Orange ◽  
Citrus Rootstock ◽  
Significant Difference ◽  
Fe Uptake

Iron (Fe) deficiency caused by calcareous soil is a serious problem in the cultivation of citrus (Citrus L.) trees. In this study, we report that ‘Zhique’ (Citrus wilsonii Tanaka) citrus rootstock from Chenggu county of Shaanxi province, China, shows tolerance to Fe deficiency under calcareous soil conditions. In the same calcareous field conditions, ‘Miyagawa Wase’ Satsuma mandarin (Citrus unshiu Marc.) grafted on trifoliate orange [Poncirus trifoliate (L.) Raf.] rootstock, the most commonly used rootstock, showed obvious interveinal chlorosis in young leaves, though some leaves or branches are asymptomatic, whereas no symptoms were found on those grafted on ‘Zhique’ rootstock. This was further evidenced by the fact that the chlorophyll concentration in chlorotic leaves of ‘Miyagawa Wase’ grafted on trifoliate orange was significantly lower than in those grafted on ‘Zhique’. In addition, transmission electron microscopy (TEM) analysis revealed a significant reduction of grana and stroma thylakoid of chloroplasts in chlorotic leaves. Measurement of Fe concentrations revealed that the total Fe and cell wall Fe showed no difference between ‘Zhique’ and trifoliate orange roots, whereas the ferrous Fe was significantly higher in ‘Zhique’ than trifoliate orange roots. Interestingly, both total Fe and ferrous Fe concentrations in chlorotic leaves were significantly lower than in green leaves of ‘Miyagawa Wase’ grafted on either ‘Zhique’ or trifoliate orange, whereas the cell wall Fe concentration of ‘Miyagawa Wase’ leaves only showed significant difference between the ‘Zhique’ and trifoliate orange samples. Further transcript assessment found that the Fe acquisition–related genes FIT, HA, FRO, and NRAMP were upregulated in roots of ‘Zhique’ compared with trifoliate orange, thus suggesting ‘Zhique’ might be more capable of Fe uptake under calcareous soil conditions. The novel citrus rootstock reported here could be used as an ideal material for Fe-uptake research, and as a Fe-deficiency-tolerant rootstock for citrus cultivation in calcareous soils.

scholarly journals Putative cis-regulatory elements predict iron deficiency responses in Arabidopsis roots

2019 ◽  
Author(s):  
Birte Schwarz ◽  
Christina B. Azodi ◽  
Shin-Han Shiu ◽  
Petra Bauer
Keyword(s):  
Transcription Factor ◽  
Iron Deficiency ◽  
Large Scale ◽  
Computational Models ◽  
Regulatory Elements ◽  
Transport Systems ◽  
Fe Deficiency ◽  
Grass Species ◽  
Bhlh Transcription Factor ◽  
Fe Uptake

AbstractIron (Fe) is a key cofactor in many cellular redox processes, including respiration and photosynthesis. Plant Fe deficiency (-Fe) activates a complex regulatory network which coordinates root Fe uptake and distribution to sink tissues, while avoiding over-accumulation of Fe and other metals to toxic levels. In Arabidopsis (Arabidopsis thaliana), FIT (FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR), a bHLH transcription factor (TF), is required for up-regulation of root Fe acquisition genes. However, other root and shoot -Fe-induced genes involved in Fe allocation and signaling are FIT-independent. The cis-regulatory code, i.e. the cis-regulatory elements (CREs) and their combinations that regulate plant -Fe-responses, remains largely elusive. Using Arabidopsis genome and transcriptome data, we identified over 100 putative CREs (pCREs) that were predictive of -Fe-induced up-regulation of genes in root tissue. We used large-scale in vitro TF binding data, association with FIT-dependent or FIT-independent co-expression clusters, positional bias, and evolutionary conservation to assess pCRE properties and possible functions. In addition to bHLH and MYB TFs, also B3, NAC, bZIP, and TCP TFs might be important regulators for -Fe responses. Our approach uncovered IDE1 (Iron Deficiency-responsive Element 1), a -Fe response CRE in grass species, to be conserved in regulating genes for biosynthesis of Fe-chelating compounds also in Arabidopsis. Our findings provide a comprehensive source of cis-regulatory information for -Fe-responsive genes, that advances our mechanistic understanding and informs future efforts in engineering plants with more efficient Fe uptake or transport systems.One sentence summary>100 putative cis-regulatory elements robustly predict Arabidopsis root Fe deficiency-responses in computational models, and shed light on the mechanisms of transcriptional regulation.

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