The Regulation of Iron Uptake and Possible Functions of Nicotianamine in Higher Plants

Scholz, Günter; Becker, Roswitha; Stephan, Udo W.; Rudolph, Armin; Pich, Axel

doi:10.1016/s0015-3796(88)80015-5

Cited by 45 publications

(17 citation statements)

References 52 publications

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“…In contrast to phytosiderophores that complex Fe3+ (Takagi, 1976;Kawai et al, 1988), NA forms stable complexes with Fez+ and other divalent transition metal ions (BeneS et al, 1983;Anderegg and Ripperger, 1989). This complex formation with divalent transition metal ions seems to be the primary function of NA within plants (Schreiber, 1986;Scholz et al, 1988). NA is universally distributed within the plant kingdom.…”

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confidence: 97%

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Subcellular Localization and Characterization of Excessive Iron in the Nicotianamine-less Tomato Mutant chloronerva

1995

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To understand the function of the Fe2+-complexing compound nicotianamine (NA) in the iron metabolism of plants we have localized iron and other elements in the NA-containing tomato wild type (Lycopersicon esculentum) and its NA-free mutant chloronerva by quantitative x-ray microanalysis. Comparison of element composition of the rhizodermal cell walls indicated that the wild type accumulated considerable amounts of iron and phosphorus in the cell wall, whereas in the mutant iron and phosphorus were detected in the cytoplasm and vacuoles of the rhizodermis. In mutant leaves containing high iron concentrations in the symplast, electron-dense inclusions were detected in chloroplasts and phloem. Such particles, consisting mainly of iron and phosphorus, were never found in the wild type and were very rarely detected in young chlorotic mutant leaves or after treatment of the mutant with NA. For further characterization the electron-dense inclusions in mutant leaves were isolated and compared by sodium dodecyl sulfate-gel electrophoresis and immunoblotting to ferritin from iron-loaded Phaseolus vulgaris leaves. Antibodies raised against purified Phaseolus leaf ferritin were used. Neither in mutant nor in wild type (iron loaded and control) was ferritin protein detected. These results suggest that the electron-dense inclusions in mutant leaves are not identical with ferritin. It is concluded that NA is necessary to complex ferrous iron in a soluble and available form within the cells. In the absence of NA the precipitation of excessive iron in the form of insoluble ferric phosphate compounds could protect the cells from iron overload.

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confidence: 97%

“…either to the nutrient solution or to the leaves (for reviews, see Scholz et al, 1988Scholz et al, ,1992. The mutant translocates large amounts of iron to the shoot, leading to an accumulation of iron, especially in older leaves .…”

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Subcellular Localization and Characterization of Excessive Iron in the Nicotianamine-less Tomato Mutant chloronerva

1995

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“…62219004 and No. 62303014) from the Ministry of Education, Science and Culture, Japan 2Abbreviations: MAs, mugineic acid-family phytosiderophores; DMA, 2'-deoxymugineic acid; NA, nicotianamine; SAM, S-adenosyl-L-methionine; Taps, N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid also reported the cell-free system from suspension culture of Nicotiana megalosiphon (19).On the above-mentioned hypothetical pathway of the biosynthesis of MAs, NA is a key substance, not only because its structure is much similar to MAs but also because the biosynthetic steps from NA to MAs can be thought to be evolutionally acquired by the 'strategy 2' plants, or lost by the 'strategy 1' plants: NA is widely distributed among the plants of both strategy 1 and 2, but MAs can be found only in some graminaceous plants (1,3,17). Nevertheless, there has been no direct evidence that NA is converted to DMA.…”

mentioning

confidence: 99%

“…On the above-mentioned hypothetical pathway of the biosynthesis of MAs, NA is a key substance, not only because its structure is much similar to MAs but also because the biosynthetic steps from NA to MAs can be thought to be evolutionally acquired by the 'strategy 2' plants, or lost by the 'strategy 1' plants: NA is widely distributed among the plants of both strategy 1 and 2, but MAs can be found only in some graminaceous plants (1,3,17). Nevertheless, there has been no direct evidence that NA is converted to DMA.…”

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confidence: 99%

Biosynthesis of Phytosiderophores

Shojima¹,

Nishizawa²,

Fushiya³

et al. 1990

Plant Physiol.

248

104

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2'-Deoxymugineic acid (DMA), one of mugineic acid-family phytosiderophores (MAs), was synthesized in vitro both from Lmethionine and from nicotianamine (NA) with a cell-free system derived from root tips of iron-deficient barley (Hordeum vulgare L.). The reactions producing DMA from NA needed an amino group acceptor (i.e. 2-oxoglutarate, pyruvate, or oxalacetic acid) and a reductant (i.e. NADH or NADPH). The activity of the enzymes to produce NA from L-methionine was the highest at about pH 9.This biosynthetic activity was markedly induced by iron-deficiency stress. The synthesis of NA from S-adenosyl-L-methionine was more efficient than from L-methionine. From the results with the cell-free system reported here, we propose a revised biosynthetic pathway of MAs.Plants with 'Strategy 2' for iron acquisition (16) excrete iron-chelators, called phytosiderophores, from the roots to solubilize the external insoluble Fe3", and the amount of the secreted phytosiderophores increases under iron deficiency stress. MAs2 are the only examples of the phytosiderophores known so far (21). Their chemical properties (9,14,20,23) and their physiological significance (4,7,8,11,12,15,22) have already been established.The biosynthetic pathway of MAs is presently considered to be that three molecules of L-methionine are combined to form NA, which is then converted to DMA by deamination and hydroxylation at the 3"-carbon, and subsequent series of hydroxylation of DMA lead to other members of MAs. This pathway has been supported by the incorporation of L-['4C] methionine or L-['3C]methionine into MAs in vivo (5, 10) and the inhibition of deamination in vivo (6, 18). To characterize the biosynthesis furthermore, we recently developed a cellfree system for the biosynthesis of NA from L-methionine, using crude protein fraction from the roots of iron-deficient barley (18). For a larger scale preparation of the sample, we 'Partly supported by Grant-in-Aid (No. 62219004 and No. 62303014) from the Ministry of Education, Science and Culture, Japan 2Abbreviations: MAs, mugineic acid-family phytosiderophores; DMA, 2'-deoxymugineic acid; NA, nicotianamine; SAM, S-adenosyl-L-methionine; Taps, N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid also reported the cell-free system from suspension culture of Nicotiana megalosiphon (19).On the above-mentioned hypothetical pathway of the biosynthesis of MAs, NA is a key substance, not only because its structure is much similar to MAs but also because the biosynthetic steps from NA to MAs can be thought to be evolutionally acquired by the 'strategy 2' plants, or lost by the 'strategy 1' plants: NA is widely distributed among the plants of both strategy 1 and 2, but MAs can be found only in some graminaceous plants (1,3,17). Nevertheless, there has been no direct evidence that NA is converted to DMA. The principal reason for this lack of data may be that there have been no systems to produce DMA in vitro.We thus improved our previous cell-free system in the following order. First, the cel...

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“…Esto hace suponer que el Fe en el citoplasma está unido a algún tipo de compuesto que evite estos efectos. Distintos autores (Pich et al, 1997;Scholz et al, 1988) (Landsberg, 1984;Von Wirén et al, 1999;Hell y Stephan, 2003) y transportado a larga distancia a las partes superiores de la planta unido principalmente a citrato (Chaney, 1989;López-Millán et al, 2001;Tiffin, 1966a,b), a otros aniones orgánicos, como malato o malonato (Brown, 1963;Chaney, 1989) e incluso con otro tipo de sustancias orgánicas (Cataldo et al, 1988).…”

Section: Transporte Del Fe En El Interior De La Planta Y Distribuciónunclassified

Respuestas Del Sistema De Absorción De Hierro en Las Raíces De Los Cítricos Ante Diferentes Condiciones Clorosantes Del Medio

Cuenca¹,

Rus²

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INFORMAN que,Dª Mary-Rus Martínez Cuenca, Ingeniera Agrónoma, ha realizado bajo nuestra dirección el trabajo que, con el título "Respuestas del sistema de absorción de hierro en las raíces de los cítricos ante diferentes condiciones clorosantes del medio", presenta para optar al grado de Doctora Ingeniera Agrónoma.Para que así conste a los efectos oportunos, firman el presente documento en Moncada a 28 de septiembre de 2012. Fdo. D. Francisco Legaz ParedesFdo. D. Eduardo Primo Millo RESUMENLa clorosis férrica es uno de los estreses abióticos más importantes para las plantas, y como tal, resulta un problema agrícola muy extendido especialmente para aquellos cultivos que se desarrollan en terrenos calizos, como es el caso de los cítricos en la Comunidad Valenciana.El objetivo de este trabajo fue caracterizar el sistema de absorción de hierro en los cítricos y su respuesta ante distintas situaciones clorosantes que comprometen la disponibilidad del elemento, provocando la deficiencia deFe en la planta. Los componentes del sistema de absorción del Feacidificación del medio, reducción del Fe(III), transporte a través de la membrana y alteración de la síntesis de ácidos orgánicos-, se analizaron a nivel fisiológico, bioquímico y molecular, en condiciones de ausencia de Fe externo, presencia de bicarbonato (HCO 3 -) y de otros micronutrientes como zinc (Zn) y manganeso (Mn). A més a més, s'aprecia que totes les respostes a la deficiència de Fe dels arrels estan metabòlicament relacionades les unes amb les altres i collaboren en l'absorció d'este element per la planta mitjançant la solubilització del Fe amb l'acidificació de la rizosfera, la reducció del ió Fe 3+ a Fe 2+ (més absorbible per la planta), i l'activació dels transportadors de ferro de la membrana plàsmica del a rrel. El nivell de tolerància dels cítrics a la clorosi fèrrica està determinat pel grau de resposta dels components del sistema d'absorció de Fe davant d'una situació clorosant, on el paper de l'enzim FC-R és especialment important. ABSTRACTIron chlorosis is one of the main abiotic stress factors in plants, and as such, is a widespread agricultural problem especially affecting those crops grown on calcareous soils, as in the case of citrus in the Valencia region.The aim of this study was to characterize the iron uptake system in

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The Regulation of Iron Uptake and Possible Functions of Nicotianamine in Higher Plants

Cited by 45 publications

References 52 publications

Subcellular Localization and Characterization of Excessive Iron in the Nicotianamine-less Tomato Mutant chloronerva

Subcellular Localization and Characterization of Excessive Iron in the Nicotianamine-less Tomato Mutant chloronerva

Biosynthesis of Phytosiderophores

Respuestas Del Sistema De Absorción De Hierro en Las Raíces De Los Cítricos Ante Diferentes Condiciones Clorosantes Del Medio

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