Abstract Nicotianamine synthase (NAS), the key enzyme in biosynthetic pathway for mugineic acid family of phytosiderophores, catalyzes trimerization ofS-adenosylmethionine to form one molecule nicotianamine. We purified NAS protein and isolated genesnas1, nas2, nas3,nas4, nas5-1, nas5-2, andnas6, which encode NAS-like proteins from Fe-deficient barley (Hordeum vulgare L. cv Ehimehadaka no. 1) roots. Escherichia coli expressingnas1 showed activity, confirming that this gene encodes a...

To address the problem of iron-deficiency anemia, one most prevalent human micronutrient deficiencies globally, iron-biofortified rice was produced using three transgenic approaches: by enhancing iron storage in grains via expression protein ferritin endosperm-specific promoters, translocation through overproduction natural metal chelator nicotianamine and flux into endosperm means iron(II)-nicotianamine transporter OsYSL2 under control an promoter sucrose promoter. Our results indicate that...

Nicotianamine (NA), a chelator of metals, is ubiquitously present in higher plants. In graminaceous plants, NA biosynthetic precursor phytosiderophores and thus crucial component for iron (Fe) acquisition. Here, we show that three rice synthase (NAS) genes, OsNAS1, OsNAS2, OsNAS3 are expressed cells involved long-distance transport Fe the genes differentially regulated by Fe. OsNAS1 OsNAS2 transcripts were detected Fe-sufficient roots but not leaves, levels both increased markedly leaves...

In humans, iron (Fe) and zinc (Zn) deficiencies result in major worldwide health problems. Transgenic technologies to produce Fe- Zn-biofortified rice varieties offer a promising potential solution. Nicotianamine, the precursor of phytosiderophores, chelates Fe2+ Zn2+ plays an important role transporting these metals both vegetative reproductive organs within plant. Our objective was increase Fe Zn contents grains by overexpressing barley nicotianamine synthase gene HvNAS1....

Nicotianamine, a plant-derived chelator of metals, is produced by the trimerization S-adenosylmethionine catalyzed nicotianamine synthase. We established transgenic Arabidopsis and tobacco plants that constitutively overexpress barley synthase gene. Nicotianamine overexpression resulted in increased biosynthesis plants, which conferred enhanced tolerance high levels particularly nickel, to plants. Promoter activities four genes were all response excess suggesting plays an important role...

Summary Nicotianamine (NA) is an intermediate in the biosynthetic pathway of mugineic acid family phytosiderophores (MAs), which are crucial components iron acquisition apparatus graminaceous plants. In non‐graminaceous plants, NA thought to be essential chelator for metal cation homeostasis. Thus plays a key role Fe metabolism and homeostasis all higher synthase (NAS, EC 2.5.1.43) catalyzes trimerization S‐adenosylmethionine form one molecule NA. Barley, plant that resistant deficiency,...

Nicotianamine synthase (NAS) is an enzyme that critical for the biosynthesis of mugineic acid family phytosiderophores in graminaceous plants, and homeostasis metal ions nongraminaceous plants. We isolated one genomic NAS clone, ZmNAS3, two cDNA clones, ZmNAS1 ZmNAS2, from maize (Zea mays cv Alice). In agreement with increased secretion Fe deficiency, ZmNAS2 were positively expressed only Fe-deficient roots. contrast, ZmNAS3 was under Fe-sufficient conditions, negatively regulated by...

Common reed (Phragmites australis) is a well known salt-tolerant plant and it suggested that reeds recover Na(+) in the xylem sap of shoot base (basal part shoot), store temporarily base, release into phloem sap, then retranslocate to roots. To investigate whether retained reeds, confocal laser scanning microscope (CLSM) observations were conducted using an intracellular Na(+)-specific fluorescent probe. The CLSM revealed produced large number starch granules at when salt-stressed,...

It has been reported that supply of nitrate to culture solution rapidly and reversibly inhibits nodule growth nitrogen fixation activity soybean. In this study, the effects ammonium, urea, or glutamine on are compared with for nitrate. Soybean plants were cultivated a nitrogen-free nutrient solution, then 1 mM-N nitrate, glutamine, urea supplied from 12 DAP until 17 DAP. Repression at observed by like although inhibitory milder than The removal solutions after treatments resulted in recovery...

We analyzed the directions and rates of translocation sodium ions (Na+) within tissues a salt-tolerant plant, common reed [Phragmites australis (Cav.) Trin. ex Steud.], salt-sensitive rice (Oryza sativa L.), under constant high-salt conditions using radioactive 22Na tracer positron-emitting imaging system (PETIS). First, test plants were incubated in nutrient solution containing 50 mM NaCl trace level for 24 h (feeding step). Then original was replaced with fresh but no 22Na, which remained...

The nutrients absorbed in the plant roots are transported to shoots through xylem. effects of concentrations N, P, K, Mg, and Ca a culture solution on N transport forms have not been fully elucidated. In this study, rice plants were grown with five for three days, major compounds xylem sap determined. control plants, nitrate, glutamine, asparagine principal compounds. decreased consistently decrease concentration solution. Different P did affect components. With lower K concentrations, only...

The activities of nicotianamine aminotransferase, one the enzymes for biosynthesis mugineic acid-family phytosiderophores, were examined in six graminaceous species. enzyme induced by Fe-deficiency treatments all species tested and had a considerable correlation to amounts secreted acids.

Phosphorus (P) is an essential major element for plants. The absorption and transport of P are important soybean growth yield, including nodule N2 fixation. Through analysis xylem sap, we investigated how nodulated plants absorb PO4 via the roots it to shoot. were treated with 0, 50, 250 μM concentrations 1, 3, 7, 15 days. concentration in sap significantly decreased after 1 day deprivation, then gradually high-concentration (250 PO4) treatment increased at 7- 15-day timepoints but not 1- or...

Abstract Nicotianamine synthase (NAS) catalyzes the trimerization of S-adenosylmethionine to form one molecule nicotianamine (NA). NA is present in all plants; it chelates metal cations, and considered play a role homeostasis plants. Moreover, graminaceous monocotyledonous plants, an essential intermediate biosynthesis mugineic acid family phytosiderophores (MAs). In order identify gene encoding NAS dicotyledonous Arabidopsis thaliana databases were searched using nucleotide sequence from...

Because of the high demand for iron photosynthetic apparatus in thylakoid membranes, deficiency primarily affects electron transfer between two photosystems (PSI and PSII), resulting photooxidative damage plants. However, barley, PSII is protected against photoinhibition, plant survives even with a low content its chlorotic leaves. In this study, we report an adaptation mechanism barley to deficiency, which concomitant remodeling antenna system. Transcriptome analysis revealed that long-term...

Plants allocate large proportions of nitrogen (N) and iron (Fe) – principal elements in the photosynthetic electron transport system to leaf chloroplasts. Although molecular mechanisms overcome N deficiency have been intensively studied, acclimation apparatus Fe higher plants remains be further investigated. We previously reported about effective strategies chloroplasts an Fe-deficiency-tolerant crop, barley, which allow photosynthesis under Fe-deficient conditions, not relying solely on...

The effects of nodulation on N metabolism in soybean plants supplied with various forms are not fully understood. Ureides the principal transported from nodules, but nitrate and asparagine primary compounds roots NO3-. In this research, 1-day treatments NO3-, NH4+, urea, or NO3- + NH4+ metabolite concentrations xylem sap each organ were compared between nodulated non-nodulated soybeans. Capillary electrophoresis colorimetry used for analysis. an N-free solution, ureides major metabolites,...

Leaf iron (Fe) contents in Fe-deficiency-tolerant plants are not necessarily higher than that Fe-deficiency-susceptible ones, suggesting an unknown mechanism involved saving and allowing the efficient use of minimal Fe. To quantitatively evaluate difference Fe economy for photosynthesis, we compared ratio CO2 assimilation rate to content newly developed leaves as a novel index photosynthetic iron-use efficiency (PIUE) among 23 different barley (Hordeum vulgare L.) varieties. Notably,...

Soybean (Glycine max (L.) Merr.) plants form root nodules and fix atmospheric dinitrogen, while also utilizing the combined nitrogen absorbed from roots. In this study, nodulated soybean were supplied with 5 mM N nitrate, ammonium, or urea for 3 days, changes in metabolite concentrations xylem sap each organ analyzed. The ureide concentration was highest control that an N-free nutrient solution, but nitrate asparagine principal compounds treatment. both similar between ammonium treatments....