Fe Uptake Research Articles

Grain and shoot iron (Fe) content and root phytosiderophore release are the major determinants of Fe-deficiency tolerance index (FeDTI) and the reliable screening markers to breed Fe-efficient rice (Oryza sativa L.)

There is a need to exploit the genetic variability in rice to improve the Fe deficiency tolerance, particularly under aerobic conditions, and to improve the Fe uptake and accumulation in the grain to facilitate biofortification. The present research was conducted to ascertain the regulators and determinants of Fe-deficiency tolerance in rice. Fifty-seven diverse genotypes were investigated under Fe-deficient (1 µM, FDS, -Fe) and Fe-sufficient (100 µM, FSS, +Fe) nutrient solution cultures for growth and physiological attributes, Fe uptake and accumulation and root release of phytosiderophores (PS), etc., and Fe-deficiency tolerance index (FeDTI). A strong positive correlation was observed between root traits and the PS release. Further, a higher release of PS was evidenced as a major determinant of shoot Fe and grain Fe in rice particularly under Fe deficiency. Based on FeDTI, a total of ten rice genotypes were identified, and their Fe deficiency response was further validated on Fe deficient (∼2.1 ppm Fe, FeDS) and Fe-sufficient soils (∼10 ppm Fe, FeSS) in pot culture. Maintenance of high active Fe content and consequently a higher leaf chlorophyll content throughout the plant growth were extremely important determinants of grain yield and grain Fe fortification in rice under Fe deficiency than under the Fe sufficient condition. Based on the FeDTI, this study further identifies the Fe-deficiency tolerant rice genotypes which can be exploited through conventional and molecular breeding approaches to improve the Fe uptake efficiency and grain Fe content of the high-yielding rice genotypes.

Effects of biofertilizer on the production of bell pepper (Capsicum annuum L.) in greenhouse

Biological fertilizers are useful sources of plant nutrients that enhance crop growth and quality, produce plant hormones, and contribute to sustainable crop production by maintaining soil fertility. The effect of arbuscular mycorrhizal fungi (AMF) and plant growth promoting rhizobacteria (PGPRs) applications in greenhouses on bell pepper (Capsicum annuum L. Nervin) has been studied by conducting a split plot experiment in three replications using a randomized complete block design. The biofertilizers included AMF inoculations (Rhizophagus irregularis + Funneliformis mosseae), and three different bacterial inoculations (Azotobacter chroococcum + Azospirillum lipoferum; Enterobacter cloacae + Pseudomonas putida; Bacillus subtilis + Bacillus amyloliquefaciens) and non-inoculation as a control with two levels of organic fertilizers (with and without).The organic treatment fertilizer, in combination with the inoculation of E. cloacae + P. putida or A. chroococcum + A. lipoferum, as well as AMF, significantly increased the microbial population within the rhizosphere compared to the control. In all treatments, fruit yield increased, with the highest value (15.94 kg m−2) recorded in the AMF treatment, indicating an increase of 18% over the control. All inoculations significantly increased total phenol and ascorbic acid levels in fruit when organic fertilizer was applied. The most significant N uptake was observed in A. crococcum + A. lipoform inoculation, while the most significant Fe uptake was observed in AMF. It was found that all inoculations significantly increased P, K, and Zn uptake. In conclusion, A combination of organic fertilizer and mycorrhizal or (Azotobacter chroococcum + Azospirillum lipoferum) inoculations increased the productivity and quality of bell peppers grown in greenhouses.

Overexpressing ATP Sulfurylase Improves Fe-Deficiency Tolerance in Apple Calli and Tobacco

Iron (Fe) deficiency is one of the most common micronutrient deficiencies limiting crop production globally, especially in arid regions due to decreased availability of Fe in alkaline soils. The ATP sulfurylase (ATPS) gene has been reported to participate in regulating various abiotic stresses. Transcriptome data and qRT-PCR analysis revealed that the ATP sulfurylase gene MhATPS1 was notably induced by Fe-deficiency stress. Consequently, MhATPS1 (103410737) was isolated from Malus halliana, and transgenic tobacco and transgenic apple calli were successfully obtained by genetic transformation. Compared with the wild type (WT), transgenic MhATPS1 lines (transgenic tobacco and transgenic apple calli) displayed stronger resistance to Fe-deficiency treatment. To be specific, transgenic plants exhibited better growth, accumulated more Fe2+ content, had higher ferric chelate reductase (FCR) activity, and a greater active oxygen scavenging capacity. Furthermore, transgenic MhATPS1 lines up-regulated the expression of Fe uptake genes under Fe-deficit stress. Additionally, MhATPS1 transgenic lines secreted more H+ content compared to the WT. In summary, these findings indicate that the MhATPS1 gene may play a positive role in Fe-deficiency stress in both tobacco and apple calli.

PDR9 allelic variation and MYB63 modulate nutrient-dependent coumarin homeostasis in Arabidopsis.

Plant roots release phytochemicals into the soil environment to influence nutrient availability and uptake. Arabidopsis thaliana roots release phenylpropanoid coumarins in response to iron (Fe) deficiency, likely to enhance Fe uptake and improve plant health. This response requires sufficient phosphorus (P) in the root environment. Nonetheless, the regulatory interplay influencing coumarin production under varying availabilities of Fe and P is not known. Through genome-wide association studies, we have pinpointed the influence of the ABC transporter G family member, PDR9, on coumarin accumulation and trafficking (homeostasis)under combined Fe and P deficiency. We show that genetic variation in the promoter of PDR9 regulates its expression in a manner associated with coumarin production. Furthermore, we find that MYB63 transcription factor controls dedicated coumarin production by regulating both COUMARIN SYNTHASE (COSY) and FERULOYL-CoA 6'-HYDROXYLASE 1 (F6'H1) expression while orchestrating secretion through PDR9 genes under Fe and P combined deficiency. This integrated approach illuminates the intricate connections between nutrient signaling pathways in coumarin response mechanisms.

Insoluble-Phytate Improves Plant Growth and Arsenic Accumulation in As-Hyperaccumulator Pteris vittata: Phytase Activity, Nutrient Uptake, and As-Metabolism.

Phytate, the principal P storage in plant seeds, is also an important organic P in soils, but it is unavailable for plant uptake. However, the As-hyperaccumulator Pteris vittata can effectively utilize soluble Na-phytate, while its ability to utilize insoluble Ca/Fe-phytate is unclear. Here, we investigated phytate uptake and the underlying mechanisms based on the phytase activity, nutrient uptake, and expression of genes involved in As metabolisms. P. vittata plants were cultivated hydroponically in 0.2-strength Hoagland nutrient solution containing 50 μM As and 0.2 mM Na/Ca/Fe-phytate, with 0.2 mM soluble-P as the control. As the sole P source, all three phytates supported P. vittata growth, with its biomass being 3.2-4.1 g plant-1 and Ca/Fe-phytate being 19-29% more effective than Na-phytate. Phytate supplied soluble P to P. vittata probably via phytase hydrolysis, which was supported by 0.4-0.7 nmol P min-1 g-1 root fresh weight day-1 phytase activity in its root exudates, with 29-545 μM phytate-P being released into the growth media. Besides, compared to Na-phytate, Ca/Fe-phytate enhanced the As contents by 102-140% to 657-781 mg kg-1 in P. vittata roots and by 43-86% to 1109-1447 mg kg-1 in the fronds, which was accompanied by 21-108% increase in Ca and Fe uptake. The increased plant As is probably attributed to 1.3-2.6 fold upregulation of P transporters PvPht1;3/4 for root As uptake, and 1.8-4.3 fold upregulation of arsenite antiporters PvACR3/3;1/3;3 for As translocation to and As sequestration into the fronds. This is the first report to show that, besides soluble Na-phytate, P. vittata can also effectively utilize insoluble Ca/Fe-phytate as the sole P source, which sheds light onto improving its application in phytoremediation of As-contaminated sites.

Pseudomonas putida configures Arabidopsis root architecture through modulating the sensing systems for phosphate and iron acquisition

Iron (Fe) and phosphate (Pi) are two essential nutrients that are poorly available in the soil and should be supplemented either as fertilizers or organic amendments to sustain crop production. Currently, determining how rhizosphere bacteria contribute to plant mineral nutrient acquisition is an area of growing interest regarding its potential application in agriculture. The aim of this study was to investigate the influence of root colonization by Pseudomonas putida for Arabidopsis growth through Fe and Pi nutritional signaling. We found that root colonization by the bacterium inhibits primary root elongation and promotes the formation of lateral roots. These effects could be related to higher expression of two Pi starvation-induced genes and AtPT1, the major Pi transporter in root tips. In addition, P. putida influenced the accumulation of Fe in the root and the expression of different elements of the Fe uptake pathway. The loss of function of the protein ligase BRUTUS (BTS), and the bHLH transcription factors POPEYE (PYE) and IAA-LEUCINE RESISTANT3 (ILR3) compromised the root branching stimulation triggered by bacterial inoculation while the leaf chlorosis in the fit1 and irt1–1 mutant plants grown under standard conditions could be bypassed by P. putida inoculation. The WT and both mutant lines showed similar Fe accumulation in roots. P. putida repressed the expression of the IRON-REGULATED TRANSPORTER 1 (IRT1) gene suggesting that the bacterium promotes an alternative Fe uptake mechanism. These results open the door for the use of P. putida to enhance nutrient uptake and optimize fertilizer usage by plants.

Fe(III) transporter OsYSL15 may play a key role in the uptake of Cr(III) in rice (Oryza sativa L.)

Due to the widely discharge of chromium (Cr) by mining and smelting industries, etc., contamination of paddy soils and rice has become serious problems. Therefore it is crucial to explore how rice takes up Cr. Cr(III) is the most common Cr form in the long-term water flooding paddy soils. Here, we demonstrate that OsYSL15, a key gene for Fe(III) uptake, is equally applicable for Cr(III) uptake in rice. Firstly, the antagonistic effect of Cr(III) and Fe(III) in the uptake process was found. Rice could accumulate more Cr(III) under Fe-deficient conditions. And the Fe(III) content in the protoplasts of rice root cells gradually decreased with the increase exposure of Cr(III). Knockdown of OsYSL15 in rice significantly reduced the Cr(III) uptake rate. Compared with wild type rice, the accumulation of Cr(III) in OsYSL15 mutant was decreased by 40.7%− 70.6% after gene editing. These results indicate that OsYSL15 is a key gene responsible for Cr(III) uptake in rice, which can guide the screening or genetic modification for low-Cr-accumulation rice varieties.

Isolation, heterologous expression, and functional determination of an iron regulated transporter (IRT) gene involved in Fe2+ transport and tolerance to Fe2+ deficiency in Vitis vinifera

In plants, iron (Fe) regulated transporters (IRT) play important roles in uptake and transport of Fe that contributes to plant growth and development. However, biological functions of IRT transporters in fruit trees are still unknown. This study isolated 10 VvIRT genes from ‘Marselan’ grape, with varying expression levels across different tissues/organs, particularly enhanced under Fe depletion, especially in roots. Notably, VvIRT7 is the most abundantly expressed IRT gene in grape, beneficially restoring the Fe2+ uptake defect of yeast mutant DEY1453. Furthermore, VvIRT7 showed dominant expression in the roots of irt1/35S::IRT7 complementation lines. Overexpressing of VvIRT7 rescued the retarded growth of irt1 knockout mutant, by increasing the fresh weight, dry weight, total root length, total root surface, lateral root numbers, total leaf chlorophyll, ACO activity, NiR activity, SDH activity, and tissue Fe concentration. This study provides insights for understanding molecular mechanisms of Fe uptake and transport in grape.

Meta-topolin and silica nanoparticles induced vigorous carnation plantlet via regulation of antioxidant status and mineral absorption

This study is an attempt to explore the potential of meta-topolin (MT) and silica nanoparticles (SiNPs) in carnation micropropagation - an in vitro vitrification sensitive cut flower. Among MT concentrations (0.5 mg/L - 3.0 mg/L), 1.0 mg/L MT treatment showed a significant increase in shoot height, leaf length, chlorophyll content, dry weight and dry matter index (DM). However, MT concentration > 2.5 mg/L resulted in increased number of shoots and vitrification. Beside different concentrations SiNPs (0.1 mg/L - 3.0 mg/L) were tested in shoot multiplication, chlorophyll content and DM increased; in contrast, the number of shoots, shoot height and other growth indicators all decreased significantly. The results indicated that MT improved shoot multiplication and reduced vitrification, while SiNPs were less suitable for this stage due to limited water absorption of shoots. Interestingly, SiNPs induced compact shoot structure and stimulated root system development, as well as induced densely closed stomata. Furthermore, the presence of SiNPs increased the activities of antioxidant enzymes Catalase (CAT), Superoxide dismutase (SOD) and Ascorbate peroxidase (APX); besides, SiNPs showed negative correlation with Cu, K and Ca uptake but significantly improved Mg, Fe and Si uptake. However, the plantlets derived from SiNPs showed 2.1–2.8-fold decrease in shoot height compared to the control but significantly increased chlorophyll content, DM index, primary root length and diameter as well as lateral root formation. At the highly tested concentrations of 2.0 mg/L - 3.0 mg/L SiNPs, a decrease in growth, uptake of Mg, Fe, Si and explosion of CAT, APX and SOD antioxidant activity was found, which presumably express stress-induced SiNPs. Nevertheless, carnation plantlets derived from SiNPs showed almost complete survival and well growth in greenhouse conditions. These findings suggest that MT and SiNPs can be used to stimulate growth, reduce vitrification, and harden carnation plantlet in practical micropropagation.

Transcriptome and biochemical analysis in hexaploid wheat with contrasting tolerance to iron deficiency pinpoints multi-layered molecular process

Iron (Fe) is an essential plant nutrient that is indispensable for many physiological activities. This study is an effort to identify the molecular and biochemical basis of wheat genotypes with contrasting tolerance towards Fe deficiency. Our physiological experiments performed at the early growth stage in cv. Kanchan (KAN) showed Fe deficiency tolerance, whereas cv. PBW343 (PBW) was susceptible. Under Fe deficient condition, KAN showed delayed chlorosis, high SPAD values, and low malondialdehyde content compared to PBW, indicative of Fe deficient condition. Comparative shoot transcriptomics revealed increased expression of photosynthetic pathway genes in PBW, further suggesting its sensitivity to Fe fluctuations. Under Fe deficiency, both the cultivars showed distinct molecular re-arrangements such as high expression of genes involved in Fe uptake (including membrane transporters) and its remobilization. Specifically, in KAN these changes lead to high root phytosiderophores (PS) biosynthesis and its release, resulting in enhanced Fe translocation index. Utilizing the non-transgenic TILLING (Targeting Induced Lesions in Genomes) technology, we identified TaZIFL4.2D as a putative PS efflux transporter. Characterization of the wheat TILLING lines indicated that TaZIFL4.2 functions in PS release and Fe acquisition, thereby imparting tolerance to Fe deficiency. Altogether, this work highlights the mechanistic insight into Fe deficiency tolerance of hexaploid wheat, thus enabling breeders to select suitable genotypes to utilize nutrients for maximum yields.

Impact of Flooding-Drainage Alternation on Fe Uptake and Transport in Rice: Novel Insights from Iron Isotopes.

Iron (Fe) isotopes were utilized to provide insights into the temporal changes underlying Fe uptake and translocation during rice growth (tillering, jointing, flowering, and maturity stages) in soil-rice systems under typical flooding-drainage alternation. Fe isotopic composition (δ56Fe values) of the soil solution generally decreased at vegetative stages in flooding regimes but increased during grain-filling. Fe plaques were the prevalent source of Fe uptake, as indicated by the concurrent increase in the δ56Fe values of Fe plaques and rice plants during rice growth. The increasing fractionation magnitude from stem/nodes I to flag leaves can be attributed to the preferred phloem transport of light isotopes toward grains, particularly during grain-filling. This study demonstrates that rice plants take up heavy Fe isotopes from Fe plaque and soil solution via strategy II during flooding and the subsequent drainage period, respectively, thereby providing valuable insights into improving the nutritional quality during rice production.

Increasing Fe Content in Rice Plants with the Application Liquid Fertilizer of Moringa oleifera and Golden Snail

Increasing iron (Fe) content in rice is needed because Fe is a critical mineral that plays a crucial role in body metabolisms, such as a form of hemoglobin, antibody production, and a catalyst for several compounds. Meanwhile, the Fe absorption by rice plants is relatively low. Moringa oleifera and golden snail contain high Fe, potentially liquid fertilizer ingredients. This research aims to increase Fe uptake and Fe content of rice plants by application of liquid fertilizer of Moringa oleifera and golden snail. The study used a completely randomized design with two factors. The first factor is the composition of liquid organic fertilizer (P), six levels (P0: without fertilizer, P1: fresh extract of Moringa leaf, P2: fermented Moringa leaf, P3: fresh extract of Golden snail, P4: fermented Golden snail, P5: Mixed 1:1 by volume fermented of Moringa leaf and golden snail). The second factor is liquid fertilizer concentrations (K), which are four levels (K1: 2%, K2: 4%, K3: 6%, and K4: 8% concentration). Repetition of treatment three times. The results showed that the treatment affected increasing fresh weight of the plant, dry weight of the plant, 100 grain weight, number of leaves, total chlorophyll, and Fe content. The fermented mixture of Moringa and golden snail at 4% concentration increased the Fe available in the soil by 6,677% or 4,788% higher than the control. The fermented Moringa leaf with an 8% concentration increased Fe in rice, which was 8,165% or 30.50% higher than the control.

Characterization of a Southern Ocean deep chlorophyll maximum: Response of phytoplankton to light, iron, and manganese enrichment

AbstractSouthern Ocean phytoplankton growth is limited by low iron (Fe) supply and irradiance, impacting the strength of the biological carbon pump. Unfavorable upper ocean conditions, such as low nutrient concentrations, can lead to the formation of deep chlorophyll or biomass maxima (DCM/DBM). While common in the Southern Ocean, these features remain understudied due to their subsurface location. To increase our understanding of their occurrence, we studied the responses of phytoplankton communities from a Southern Ocean DCM to increasing light, Fe, and manganese (Mn) levels. The DCM communities were light‐ and Fe‐limited, but light limitation did not increase phytoplankton Fe requirements. The greatest physiological responses were observed under combined Fe/light additions, which stimulated macronutrient drawdown, biomass production and the growth of large diatoms. Combined Mn/light additions induced subtle changes in Fe uptake rates and community composition, suggesting species‐specific Mn requirements. These results provide valuable information on Southern Ocean DCM phytoplankton physiology.

Ectomycorrhizal fungi enhance pine growth by stimulating iron-dependent mechanisms with trade-offs in symbiotic performance.

Iron (Fe) is crucial for metabolic functions of living organisms. Plants access occluded Fe through interactions with rhizosphere microorganisms and symbionts. Yet, the interplay between Fe addition and plant-mycorrhizal interactions, especially the molecular mechanisms underlying mycorrhiza-assisted Fe processing in plants, remains largely unexplored. We conducted mesocosms in Pinus plants inoculated with different ectomycorrhizal fungi (EMF) Suillus species under conditions with and without Fe coatings. Meta-transcriptomic, biogeochemical, and X-ray fluorescence imaging analyses were applied to investigate early-stage mycorrhizal roots. While Fe addition promoted Pinus growth, it concurrently reduced mycorrhiza formation rate, symbiosis-related metabolites in plant roots, and aboveground plant carbon and macronutrient content. This suggested potential trade-offs between Fe-enhanced plant growth and symbiotic performance. However, the extent of this trade-off may depend on interactions between host plants and EMF species. Interestingly, dual EMF species were more effective at facilitating plant Fe uptake by inducing diverse Fe-related functions than single-EMF species. This subsequently triggered various Fe-dependent physiological and biochemical processes in Pinus roots, significantly contributing to Pinus growth. However, this resulted in a greater carbon allocation to roots, relatively reducing the aboveground plant carbon content. Our study offers critical insights into how EMF communities rebalance benefits of Fe-induced effects on symbiotic partners.

Transcriptome analysis of iron over-accumulating Arabidopsis genotypes uncover putative novel regulators of systemic and retrograde signaling.

On account of its competence to accept and donate electrons, iron (Fe) is an essential element across all forms of life, including plants. Maintaining Fe homeostasis requires precise orchestration of its uptake, trafficking, and translocation in order to meet the demand for Fe sinks such as plastids. Plants harboring defects in the systemic Fe transporter OPT3 (OLIGOPEPTIDE TRANSPORTER 3) display constitutive Fe deficiency responses and accumulate toxic levels of Fe in their leaves. Similarly, ectopic expression of IRONMAN (IMA) genes, encoding a family of phloem-localized signaling peptides, triggers the uptake and accumulation of Fe by inhibiting the putative Fe sensor BRUTUS. This study aims at elucidating the mechanisms operating between OPT3-mediated systemic Fe transport, activation of IMA genes in the phloem, and activation of Fe uptake in the root epidermis. Transcriptional profiling of opt3-2 mutant and IMA1/IMA3 overexpressing (IMA Ox) lines uncovered a small subset of genes that were consistently differentially expressed across all three genotypes and Fe-deficient control plants, constituting potential novel regulators of cellular Fe homeostasis. In particular, expression of the the F-box protein At1g73120 was robustly induced in all genotypes, suggesting a putative function in the posttranslational regulation of cellular Fe homeostasis. As further constituents of this module, two plastid-encoded loci that putatively produce transfer ribonucleic acid (tRNA)-derived small ribonucleic acids are possibly involved in retrograde control of root Fe uptake.

Micronutrient Fe and Mn uptake from peat by marigold and petunia

Peat substrates have the potential to function as micronutrient sources such as iron (Fe) and manganese (Mn). Typically, when planning fertilization program for crops, the components of peat substrates are not taken into account. The objective was to quantify potentially plant-available micronutrients of Fe and Mn from peat substrates by floriculture species when no additional Fe and/or Mn were applied in the fertilizer solution. Greenhouse experiments were conducted using Tagetes erecta ‘Atlantis Primrose’ marigold (iron-efficient) and Petunia x hybrida ‘Celebrity Pink Morn’ petunia (iron-inefficient) to compare extractable Fe and Mn from two peat sources with actual plant uptake of these nutrients by the plants. In Experiment 1, marigold was grown hydroponically in plastic tubs using four different nutrient solutions: complete, without Fe, without Mn, and without both Fe and Mn. Within a period of less than two weeks after transplant, the absence of Fe and Mn severely limited marigold growth. The hydroponic study highlighted the importance of providing both Fe and Mn nutrients immediately after sowing to support normal marigold growth. In Experiment 2, both marigold and petunia were grown from seed in two peat substrates (Blackmore seedling peat “BM peat” and Sunshine Professional Black Bale peat “SG peat”) and an acid-washed sand substrate. Each peat was limed at 3 g.L−1 of reagent grade CaCO3 resulting in an initial substrate-pH of 5.0 for SG peat and 5.5 for BM peat. Four nutrient solutions [(a) complete, or complete with (b) no Fe, (c) no Mn, and (d) no Fe or Mn] were applied with each irrigation without leaching. Initial substrate nutrient levels were extracted using the SME (saturated medium extract) method using either water (SMEW) or 0.005 M DTPA (diethylenetriamine-pentaacetic acid, SMED) as extractants. Over a 5-week period (during the vegetative, non-blooming stage), peat substrates provided sufficient Fe and Mn for marigold, but iron deficiency symptoms were observed in marigolds grown in sand without Fe fertilizer. Petunia plants developed iron deficiency symptoms in all substrates without Fe fertilizer. The absence of Mn fertilizer, however, did not have a significant impact on petunia growth and health, indicating that peat substrates likely provided adequate Mn for non-symptomatic petunia plant growth. The micronutrient Fe and Mn budget analysis suggested that the SMEW method underestimated the availability of Fe and Mn to the plants, whereas the SMED method may have overestimated the extractable Fe and Mn levels in relation to the actual tissue uptake. Overall, the peat substrates showed a high potential for providing Fe and Mn in quantities sufficient for the initial growth of iron-efficient marigold, but was inadequate for iron-inefficient petunia.

English

The canola is an important oilseed crop of the world and Pakistan that grows in a substantial area, but the required quality and yield of canola oil is still not enough to meet the country’s need. Iron (Fe) and Zinc (Zn) are important human nutrients and biofortification of these elements in canola oil is a challenge especially under alkaline calcareous soil conditions owing to less bioavailability of these metal ions in soil. With the same objective, the present investigation was conducted in 2 experiments (Pot and Field trials) with 7 treatments (Control, So-200 kg ha-1, Iron-3 kg ha-1, Zinc-6 kg ha-1, S+Fe, S+Zn and S+Fe+Zn) under pot and filed conditions, separately. The application of S, Fe and Zn resulted in a significant increment in canola crop growth, yield, improved plant physiology and enhanced Fe and Zn uptake and accumulation. The elemental S alone was found to be affecting these properties significantly and combined application with Fe, Zn, and Fe+Zn resulted in further increment in growth, yield, oil percentage and shoot/grain elemental components. For Fe distribution, S application with Fe enhanced its shoot and grains accumulation 16% and 14% compared to alone Fe control under pot settings while 16% and 15% higher shoot and grain Fe was observed under field trial. The shoot and grains’ Zn contents were also found to be significantly improved (10% and 9% higher Zn in shoot and grain of pot-grown canola plants while 19% and 10% increment was observed under filed investigation compared with respective controls).

Brain iron acquisition depends on age and sex in iron-deficient mice.

Adequate and timely delivery of iron is essential for brain development. The uptake of transferrin-bound (Tf) iron into the brain peaks at the time of myelination, whereas the recently discovered H-ferritin (FTH1) transport of iron into the brain continues to increase beyond the peak in myelination. Here, we interrogate the impact of dietary iron deficiency (ID) on the uptake of FTH1- and Tf-bound iron. In the present study, we used C57BL/6J male and female mice at a developing (post-natal day (PND) 15) and adult age (PND 85). In developing mice, ID results in increased iron delivery from both FTH1 and Tf for both males and females. The amount of iron uptake from FTH1 was higher than the Tf and this difference between the iron delivery was much greater in females. In contrast, in the adult model, ID was associated with increased brain iron uptake by both FTH1 and Tf but only in the males. There was no increased uptake from either protein in the females. Moreover, transferrin receptor expression on the microvasculature as well as whole brain iron, and H and L ferritin levels revealed the male brains became iron deficient but not the female brains. Last, under normal dietary conditions, 55 Fe uptake was higher in the developing group from both delivery proteins than in the adult group. These results indicate that there are differences in iron acquisition between the developing and adult brain for FTH1 and Tf during nutritional ID and demonstrate a level of regulation of brain iron uptake that is age and sex-dependent.

Homeostatic iron regulatory protein drives glioblastoma growth via tumor cell-intrinsic and sex-specific responses.

Glioblastoma (GBM) displays alterations in iron that drive proliferation and tumor growth. Iron regulation is complex and involves many regulatory mechanisms, including the homeostatic iron regulator (HFE) gene, which encodes the homeostatic iron regulatory protein. While HFE is upregulated in GBM and correlates with poor survival outcomes, the function of HFE in GBM remains unclear. We interrogated the impact of cell-intrinsic Hfe expression on proliferation and survival of intracranially implanted animals through genetic gain- and loss-of-function approaches in syngeneic mouse glioma models, along with in vivo immune assessments. We also determined the expression of iron-associated genes and their relationship to survival in GBM using public data sets and used transcriptional profiling to identify differentially expressed pathways in control compared to Hfe-knockdown cells. Overexpression of Hfe accelerated GBM proliferation and reduced animal survival, whereas suppression of Hfe induced apoptotic cell death and extended survival, which was more pronounced in females and associated with attenuation of natural killer cells and CD8+ T cell activity. Analysis of iron gene signatures in Hfe-knockdown cells revealed alterations in the expression of several iron-associated genes, suggesting global disruption of intracellular iron homeostasis. Further analysis of differentially expressed pathways revealed oxidative stress as the top pathway upregulated following Hfe loss. Hfe knockdown indeed resulted in enhanced 55Fe uptake and generation of reactive oxygen species. These findings reveal an essential function for HFE in GBM cell growth and survival, as well as a sex-specific interaction with the immune response.

Growth response of clonal eucalyptus to varying levels of iron application and soil texture

Deficiency symptoms of iron (Fe) appear in eucalyptus (Eucalyptus spp.) plantations grown on different type of soils in Punjab, India. Therefore, a pot experiment was conducted to study the response of eucalyptus to application of Fe in soils of different textures. The treatments comprised of six levels of Fe as soil application (0, 15, 30, 45, 60, and 75 mg Fe kg−1 soil applied as chelated Fe through Fe-EDTA) and two foliar sprays (0.5% and 1% FeSO4·7H2O) replicated thrice in soils of three textures (loamy sand, sandy loam, and sandy clay) in a completely randomized design. Plant growth parameters, Fe concentration in soils, and Fe uptake by different plant parts were determined after nine months of eucalyptus growth. These parameters were significantly and positively influenced with the application of Fe. Dry weight of shoot and root was the highest at 30 mg Fe kg−1 whereas Fe concentration and uptake of Fe by shoot and root were the highest at 45 mg Fe kg−1. With 1% spray, the root dry weight, Fe concentration in leaves and its uptake by leaves and shoot were the highest. Loamy sand soil exhibited maximum shoot biomass and uptake response to applied Fe by eucalyptus. The Fe concentration in soil was positively and significantly related to Fe concentration (r = 0.436*–0.772**) and its uptake (r = 0.643**- 0.866**) by different plant parts. Conclusively, application of Fe to eucalyptus significantly increased the growth parameters, its uptake and response by the plants.