Iron Nutrition Influence on Cadmium Accumulation by Arabidopsis thaliana (L.) Heynh.

Taking into account the strong iron competition in the rhizosphere and the high affinity of pyoverdines for Fe(III), these molecules are expected to interfere with the iron nutrition of plants, as they do with rhizospheric microbes. The impact of Fe-pyoverdine on iron content of Arabidopsis thaliana was compared with that of Fe-EDTA. Iron chelated to pyoverdine was incorporated in a more efficient way than when chelated to EDTA, leading to increased plant growth of the wild type. A transgenic line of A. thaliana overexpressing ferritin showed a higher iron content than the wild type when supplemented with Fe-EDTA but a lower iron content when supplemented with Fe-pyoverdine despite its increased reductase activity, suggesting that this activity was not involved in the iron uptake from pyoverdine. A mutant knockout iron transporter IRT1 showed lower iron and chlorophyll contents when supplemented with Fe-EDTA than the wild type but not when supplemented with Fe-pyoverdine, indicating that, in contrast to iron from EDTA, iron from pyoverdine was not incorporated through the IRT1 transporter. Altogether these data suggest that iron from Fe-pyoverdine was not incorporated in planta through the strategy I, which is based on reductase activity and IRT1 transporter. This is supported by the presence of pyoverdine in planta as shown by enzyme-linked immunosorbent assay and by tracing 15N of 15N-pyoverdine.

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Comparison of iron acquisition from Fe–pyoverdine by strategy I and strategy II plants

Botany ◽

10.1139/b11-054 ◽

2011 ◽

Vol 89 (10) ◽

pp. 731-735 ◽

Cited By ~ 19

Author(s):

Matt Shirley ◽

Laure Avoscan ◽

Eric Bernaud ◽

Gérard Vansuyt ◽

Philippe Lemanceau

Keyword(s):

Arabidopsis Thaliana ◽

Plant Species ◽

Iron Uptake ◽

Iron Acquisition ◽

Iron Status ◽

Iron Nutrition ◽

Perennial Species ◽

Major Class ◽

Graminaceous Plants ◽

Strategy I

Iron is an essential micronutrient for plants and associated microorganisms. However, the bioavailability of iron in cultivated soils is low. Plants and microorganisms have thus evolved active strategies of iron uptake. Two different iron uptake strategies have been described in dicotyledonous and monocotyledonous graminaceous species. In bacteria, this strategy relies on the synthesis of siderophores. Pyoverdines, a major class of siderophores produced by fluorescent pseudomonads, were previously shown to promote iron nutrition of the dicotyledonous species Arabidopsis thaliana L. (Heynh.), whereas contradictory reports were made on the contribution of those siderophores to the nutrition of graminaceous annuals. Furthermore, no information has so far been available on graminaceous perennials. Here, the contribution of purified pyoverdine of Pseudomonas fluorescens C7R12 to the iron nutrition of two annual and perennial graminaceous plants was assessed and compared with that of two dicotyledonous plant species. Fe–Pyoverdine promoted the iron status of all plant species tested. With the exception of wheat, this promotion was more dramatic in graminaceous species than in dicotyledonous species and was the highest in fescue, a perennial species. The incorporation of 15N-labeled pyoverdine was consistent with the effect on the iron status of the plants tested.

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