Flux of protons released by wild type and ferritin over-expressor tobacco plants : effect of phosphorus and iron nutrition

Vansuyt, Gérard; Souche, Gérard; Straczek, Anne; Briat, Jean François; Jaillard, Benoît

doi:10.1016/s0981-9428(02)00005-0

Cited by 37 publications

(26 citation statements)

References 24 publications

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“…As shown with tobacco [35] and red pepper [16], H + efflux occurs only in root tips at the subapical zone near 1 cm in length: even proton influx happens at root portions 2 cm apart from the root tips [35].…”

Section: Discussionmentioning

confidence: 82%

“…This difference could be caused by morphological differences between a root tip (about 2 cm in length, with a few branches) and propagated roots (more than 10 cm of elongated roots with a great many branches). It is possible in the case of propagated roots the mature part of the roots can help increase the pH, as indicated with tobacco plants [35], whereas proton influx was not sufficiently occurred in the case of a root tip only. Interestingly, a single root tip was able to grow in iron deficient medium when it made the medium acidic by itself, where the pH was gradually decreased (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Root tip-dependent, active riboflavin secretion by Hyoscyamus albus hairy roots under iron deficiency

Higa

Miyamoto

Rahman

et al. 2008

Plant Physiology and Biochemistry

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SummaryHyoscyamus albus hairy roots with/without an exogenous gene (11 clones) were established by inoculation of Agrobacterium rhizogenes. All clones cultured under iron deficient condition secreted riboflavin from root tips into the culture medium and the productivity depended on the number and size of root tips among the clones, although the addition of sucrose was essential for riboflavin production. A decline of pH was observed before riboflavin production and root development using either a root tip or propagated roots: propagated roots were employed for further work due to their lesser variation.Additions of proton-pump inhibitors, N,N'-dicyclohexylcarbodiimide (DCCD) at 100 and 10 μM and erythrosine B at 100 μM, suppressed the pH decline at 100 and 10 μM accompanied by inhibition of riboflavin secretion and root growth; at 10 μM of erythrosine B, pH decline occurred with a moderate delay, but both growth and riboflavin efflux were inhibited. Neither inhibition of the pH decline nor riboflavin production was observed at 1 μM. To examine the necessity of acidification and riboflavin secretion by the roots themselves, artificial pH reduction of culture medium with organic acids and the addition of exogenous riboflavin with/without pH reduction were performed. When hairy roots were cultured in iron-deficient medium acidified with citric acid (pH 4.0) or malic acid (pH 3.7), pH increased rapidly to around 5 overnight, following which riboflavin production and root growth occurred. Addition of riboflavin did not affect riboflavin secretion by the roots, but acidification with citric acid (pH 4.0) helped achiever greater riboflavin production and earlier pH elevation. These results indicate that riboflavin efflux does not directly connected to active pH reduction, and more significantly active riboflavin secretion occurs by internal requirement in H. albus hairy roots under iron deficiency.

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Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Root tip-dependent, active riboflavin secretion by Hyoscyamus albus hairy roots under iron deficiency

Higa

Miyamoto

Rahman

et al. 2008

Plant Physiology and Biochemistry

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“…However, the S11 soil was subject to a significant pH increase after the P6 tobacco culture compared with the A and C5 tobaccos. Vansuyt et al (2003) showed that the culture of the P6 and C5 transformants in nutrient solution induced increasing ferric reductase and H + -ATPase activities compared to A control plant. The acidification was localised at the level of the root subapical zone and in our experiment the pH was measured using the bulk soil, leading to the dilution of the protons in the bulk soil.…”

Section: Soil Ph Before and After Culturementioning

confidence: 99%

“…Ferritin over-expression in P6 and C5 genotypes was reported to increase Fe concentration in leaves due to a Fe storage in the ferritin protein (Van Wuytswinkel et al,1999). This Fe storage induces a physiological Fe deficiency in P6 and C5 genotypes, which is accompanied by related physiological responses such as a decrease in chlorophyll concentration, an increase in ferric reductase and H + -ATPase activities (Vansuyt et al, 2003). But this increase has only been demonstrated under one growth condition in nutrient solution (Vansuyt et al, 2000).…”

Section: Metals Concentrations In Plantsmentioning

confidence: 99%

Cadmium availability at different soil pH to transgenic tobacco overexpressing ferritin

Sappin‐Didier¹,

Vansuyts

Mench³

et al. 2005

Plant Soil

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Knowledge on physiological mechanisms and plant metabolism can be used to enhance metal uptake. The capacity to uptake metals of transgenic tobaccos overexpressing ferritin in plastids (P6) or in cytoplasm (C5) and a control tobacco (A) is assessed in three polluted soils from the same soil series, with a similar Cd content, but displaying pH from 5.8 to 7 (8b2, 8b3, S11). Differences in dry leave weight were not significant between the three tobaccos growing on each soil. Iron concentration in ferritin overexpression either in P6 or in C5 tobaccos increased only on the S11 soil, which had a soil pH 7, in comparison to A tobacco. In both 8b2 and 8b3 soils at pH lower than 7, the leaf Fe content was not different between the three tobaccos. Only the P6 tobacco growing in the S11 soil accumulated more Cd, Zn and Mn compared with the A and C5 tobaccos. This increase represents, compared to A tobacco, 88% for Fe, 120% for Mn, 30% for Cd, 80% for Zn. In soils with a pH higher than 7, the ferritin synthesis is over-expressed in the P6 tobacco cells inducing a iron deficiency. These metal accumulations were increased, owing to a rhizosphere modification. The A and P6 tobaccos uptake Cd in the same soil pool. The Cd totality in the 8b2 soil is labile and in the S11 soil, the labile Cd represents 86-88% of the total Cd.

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“…To measure the Fe(III) reductase activity of tomato, root mats of 3-week old plants (after the 6-day Fe treatment period) were suspended for 15 min in 5 cm 3 of a solution of 100 mM FeNaEDTA and 300 mM ferrozine, pH 6.0 (Vansuyt et al 2003). The assay was conducted with whole plants maintained in the dark.…”

Section: Determination Of the Fe Status Of Plantsmentioning

confidence: 99%

Copper concentration in plants and in the rhizosphere as influenced by the iron status of tomato (Lycopersicon esculentum L.)

2007

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Changes of metal concentration that occur in the rhizosphere may arise from several processes including variation in the concentration of complexing ligands, pH or redox potential that can be influenced by the Fe status of the plant. The aim of this study was to assess for both acidic and calcareous, Cu-contaminated soils how Cu concentration in plants and in the rhizosphere was affected by the Fe status of a strategy I plant species. The change of soil solution pH, total solution Cu concentration and soil redox potential was monitored for 8 days in the rhizosphere of tomato (Lycopersicon esculentum L.) in response to contrasting Fe supply. The concentration of Cu in roots was enhanced under Fe deficiency in the acidic soils. Shoot Cu however did not vary with the Fe status of the plant. The plant Fe status had little effect on rhizosphere pH, redox potential or Cu concentration in solution in either acidic or calcareous soils. Marked differences in pH and solution Cu concentration were observed between rhizosphere and uncropped soils. Roots induced an increase in pH of acidic soils and a decrease in solution Cu concentration in all soils. The decrease in solution Cu concentration in acidic soils may be explained by the increase in rhizosphere pH. The proposed device provided new data on the fate of Cu in the rhizosphere and showed a positive correlation for the four soils considered together between the total Cu concentration in soil solution and root Cu concentration.

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Flux of protons released by wild type and ferritin over-expressor tobacco plants : effect of phosphorus and iron nutrition

Cited by 37 publications

References 24 publications

Root tip-dependent, active riboflavin secretion by Hyoscyamus albus hairy roots under iron deficiency

Root tip-dependent, active riboflavin secretion by Hyoscyamus albus hairy roots under iron deficiency

Cadmium availability at different soil pH to transgenic tobacco overexpressing ferritin

Copper concentration in plants and in the rhizosphere as influenced by the iron status of tomato (Lycopersicon esculentum L.)

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