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Iron deficiency affects nitrogen metabolism in cucumber (Cucumis sativus L.) plants.

Borlotti A, Vigani G, Zocchi G - BMC Plant Biol. (2012)

Bottom Line: Under Fe deficiency, only nitrate reductase (EC 1.7.1.1) activity decreased both at the root and leaf level, whilst for glutamine synthetase (EC 6.3.1.2) and glutamate synthase (EC 1.4.1.14) an increase was found.Accordingly, the transcript analysis for these enzymes showed the same behaviour except for root nitrate reductase which increased.Furthermore, it was found that amino acid concentration greatly decreased in Fe-deficient roots, whilst it increased in the corresponding leaves.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Università degli Studi di Milano, Milano, Italy.

ABSTRACT

Background: Nitrogen is a principal limiting nutrient in plant growth and development. Among factors that may limit NO3- assimilation, Fe potentially plays a crucial role being a metal cofactor of enzymes of the reductive assimilatory pathway. Very few information is available about the changes of nitrogen metabolism occurring under Fe deficiency in Strategy I plants. The aim of this work was to study how cucumber (Cucumis sativus L.) plants modify their nitrogen metabolism when grown under iron deficiency.

Results: The activity of enzymes involved in the reductive assimilation of nitrate and the reactions that produce the substrates for the ammonium assimilation both at root and at leaf levels in Fe-deficient cucumber plants were investigated. Under Fe deficiency, only nitrate reductase (EC 1.7.1.1) activity decreased both at the root and leaf level, whilst for glutamine synthetase (EC 6.3.1.2) and glutamate synthase (EC 1.4.1.14) an increase was found. Accordingly, the transcript analysis for these enzymes showed the same behaviour except for root nitrate reductase which increased. Furthermore, it was found that amino acid concentration greatly decreased in Fe-deficient roots, whilst it increased in the corresponding leaves. Moreover, amino acids increased in the xylem sap of Fe-deficient plants.

Conclusions: The data obtained in this work provided new insights on the responses of plants to Fe deficiency, suggesting that this nutritional disorder differentially affected N metabolism in root and in leaf. Indeed under Fe deficiency, roots respond more efficiently, sustaining the whole plant by furnishing metabolites (i.e. aa, organic acids) to the leaves.

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(A) Effect of Fe-deficient treatment on plant growth, (B) chlorophyll concentration and photosynthesis, (C) RT-PCR analysis of the expression of Strategy I genes (CsFRO1, CsHA1 and CsIRT1) in roots. Sampling was done at 0, 1, 3, 7 d after Fe withdraw. Data are means ± SE (n = 4). In the case of significant difference (P<0.05) values with different letters are statistically different.
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Figure 1: (A) Effect of Fe-deficient treatment on plant growth, (B) chlorophyll concentration and photosynthesis, (C) RT-PCR analysis of the expression of Strategy I genes (CsFRO1, CsHA1 and CsIRT1) in roots. Sampling was done at 0, 1, 3, 7 d after Fe withdraw. Data are means ± SE (n = 4). In the case of significant difference (P<0.05) values with different letters are statistically different.

Mentions: In this work the change in the N metabolism in response to Fe deficiency has been studied at root and leaf levels. We have re-examined the responses to Fe starvation in cucumber plants previously grown for 7 d in the presence of Fe and, after this period, deprived of the micronutrient. Figure1 shows the difference among plants grown under these conditions (Figure1A), the chlorophyll concentration, the net photosynthesis rate (Pn) and the expression of Strategy I genes. Under these conditions leaves show visible symptom of chlorosis with a concomitant decrease in both the chlorophyll content and in the Pn already after 3 d of starvation (Figure1B). In order to guarantee that Fe-deficient plants developed clear responses in agreement with Fe-deficient condition, a preliminary time course experiment on the expression of the Strategy I genes was performed at the root level (Figure1C). The expression of CsFRO1, CsHA1 and CsIRT1 increased in response to the lack of Fe in agreement with data reported in the literature[39,40].


Iron deficiency affects nitrogen metabolism in cucumber (Cucumis sativus L.) plants.

Borlotti A, Vigani G, Zocchi G - BMC Plant Biol. (2012)

(A) Effect of Fe-deficient treatment on plant growth, (B) chlorophyll concentration and photosynthesis, (C) RT-PCR analysis of the expression of Strategy I genes (CsFRO1, CsHA1 and CsIRT1) in roots. Sampling was done at 0, 1, 3, 7 d after Fe withdraw. Data are means ± SE (n = 4). In the case of significant difference (P<0.05) values with different letters are statistically different.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539955&req=5

Figure 1: (A) Effect of Fe-deficient treatment on plant growth, (B) chlorophyll concentration and photosynthesis, (C) RT-PCR analysis of the expression of Strategy I genes (CsFRO1, CsHA1 and CsIRT1) in roots. Sampling was done at 0, 1, 3, 7 d after Fe withdraw. Data are means ± SE (n = 4). In the case of significant difference (P<0.05) values with different letters are statistically different.
Mentions: In this work the change in the N metabolism in response to Fe deficiency has been studied at root and leaf levels. We have re-examined the responses to Fe starvation in cucumber plants previously grown for 7 d in the presence of Fe and, after this period, deprived of the micronutrient. Figure1 shows the difference among plants grown under these conditions (Figure1A), the chlorophyll concentration, the net photosynthesis rate (Pn) and the expression of Strategy I genes. Under these conditions leaves show visible symptom of chlorosis with a concomitant decrease in both the chlorophyll content and in the Pn already after 3 d of starvation (Figure1B). In order to guarantee that Fe-deficient plants developed clear responses in agreement with Fe-deficient condition, a preliminary time course experiment on the expression of the Strategy I genes was performed at the root level (Figure1C). The expression of CsFRO1, CsHA1 and CsIRT1 increased in response to the lack of Fe in agreement with data reported in the literature[39,40].

Bottom Line: Under Fe deficiency, only nitrate reductase (EC 1.7.1.1) activity decreased both at the root and leaf level, whilst for glutamine synthetase (EC 6.3.1.2) and glutamate synthase (EC 1.4.1.14) an increase was found.Accordingly, the transcript analysis for these enzymes showed the same behaviour except for root nitrate reductase which increased.Furthermore, it was found that amino acid concentration greatly decreased in Fe-deficient roots, whilst it increased in the corresponding leaves.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Università degli Studi di Milano, Milano, Italy.

ABSTRACT

Background: Nitrogen is a principal limiting nutrient in plant growth and development. Among factors that may limit NO3- assimilation, Fe potentially plays a crucial role being a metal cofactor of enzymes of the reductive assimilatory pathway. Very few information is available about the changes of nitrogen metabolism occurring under Fe deficiency in Strategy I plants. The aim of this work was to study how cucumber (Cucumis sativus L.) plants modify their nitrogen metabolism when grown under iron deficiency.

Results: The activity of enzymes involved in the reductive assimilation of nitrate and the reactions that produce the substrates for the ammonium assimilation both at root and at leaf levels in Fe-deficient cucumber plants were investigated. Under Fe deficiency, only nitrate reductase (EC 1.7.1.1) activity decreased both at the root and leaf level, whilst for glutamine synthetase (EC 6.3.1.2) and glutamate synthase (EC 1.4.1.14) an increase was found. Accordingly, the transcript analysis for these enzymes showed the same behaviour except for root nitrate reductase which increased. Furthermore, it was found that amino acid concentration greatly decreased in Fe-deficient roots, whilst it increased in the corresponding leaves. Moreover, amino acids increased in the xylem sap of Fe-deficient plants.

Conclusions: The data obtained in this work provided new insights on the responses of plants to Fe deficiency, suggesting that this nutritional disorder differentially affected N metabolism in root and in leaf. Indeed under Fe deficiency, roots respond more efficiently, sustaining the whole plant by furnishing metabolites (i.e. aa, organic acids) to the leaves.

Show MeSH
Related in: MedlinePlus