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Molecular, Biochemical and Ultrastructural Changes Induced by Pb Toxicity in Seedlings of Theobroma cacao L.

Reis GS, de Almeida AA, de Almeida NM, de Castro AV, Mangabeira PA, Pirovani CP - PLoS ONE (2015)

Bottom Line: The activity of guaiacol peroxidases and the expression of genes associated to synthetase of phytochelatin, SODcyt and PER increased in response to Pb.The progeny of CCN-10 x SCA-6 was more tolerant to Pb stress when compared to Catongo, since: (i) it accumulated more Pb in the roots, preventing its translocation to the shoot; (ii) it presented higher activity of peroxidases in the roots, which are enzymes involved in the elimination of excess of reactive oxygen species; and (iii) increased expression of the gene in the phytochelatin biosynthesis route.The results of the proteomic analysis were of paramount importance to differentiate the defense mechanisms used by both progenies of T. cacao.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, State University of Santa Cruz, Campus Soane Nazaré de Andrade, Rodovia Jorge Amado, km 16, 45662-900, Ilhéus, BA, Brazil.

ABSTRACT
Pb is a metal which is highly toxic to plants and animals, including humans. High concentrations of Pb have been observed in beans of T. cacao, as well as in its products. In this work, we evaluated the molecular, biochemical, and ultrastructural alterations in mature leaves and primary roots of seedlings of two progenies of T. cacao, obtained from seed germination in different concentrations of Pb (0, 0.05, 0.1, 0.2, 0.4, 0.8 g L(-1)), in the form of Pb(NO3)2. The progenies resulted from self-fertilization of Catongo and a cross of CCN-10 x SCA-6. The Pb, supplied via seminal, caused alterations in the ultrastructures of the mesophyll cells and in the amount of starch grains in the chloroplasts. The dosage of substances reactive to thiobarbituric acid showed that Pb induced lipid peroxidation. The activity of guaiacol peroxidases and the expression of genes associated to synthetase of phytochelatin, SODcyt and PER increased in response to Pb. In addition, there was alteration in the expression of stress-related proteins. The progeny of CCN-10 x SCA-6 was more tolerant to Pb stress when compared to Catongo, since: (i) it accumulated more Pb in the roots, preventing its translocation to the shoot; (ii) it presented higher activity of peroxidases in the roots, which are enzymes involved in the elimination of excess of reactive oxygen species; and (iii) increased expression of the gene in the phytochelatin biosynthesis route. The results of the proteomic analysis were of paramount importance to differentiate the defense mechanisms used by both progenies of T. cacao.

No MeSH data available.


Related in: MedlinePlus

Accumulation of mineral micronutrients (Cu, Fe, Mn and Zn) in roots (triangle), stem (circle) and leaves (rhombus) of two progenies of T. cacao exposed to increasing Pb doses.CCN-10 x SCA-6 (A,C,E e G) and Catongo (B,D,F e H). Mean values of nine replicates (± SE). The absence of error bars indicates that the size of the error does not exceed the size of the symbol. The equations of regression curves were: Cu—CCN-10 x SCA-6: ŷ = 5.43 for leaf, ŷ = 8.65–0.278x (R2 = 0.51) for stem, ŷ = 8.88–0.2753*x (R2 = 0.74) for root. Catongo: ŷ = 4.11 for leaf, ŷ = 6.57 for stem, ŷ = 3.03 for root. Fe—CCN-10 x SCA-6: ŷ = 72.07 for leaf, ŷ = 40.86 for stem, ŷ = 118.10 + 24.97*x (R2 = 0.94) for root. Catongo: ŷ = 76.21 for leaf, ŷ = 40.36 for stem, ŷ = 138.90 + 25.49*x (R2 = 0.93) for root. Mn—CCN-10 x SCA-6: ŷ = 563.1 for leaf, ŷ = 173.5 for stem, ŷ = 84.1 for root. Catongo: ŷ = 1928.84 for leaf, ŷ = 295.4 for stem, ŷ = 72.52 for root. Zn—CCN-10 x SCA-6: ŷ = 44.5 for leaf, ŷ = 74.54 for stem, ŷ = 30.35 for root. Catongo: ŷ = 54.51 for leaf, ŷ = 77.43 for stem, ŷ = 28.51 for root.
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pone.0129696.g010: Accumulation of mineral micronutrients (Cu, Fe, Mn and Zn) in roots (triangle), stem (circle) and leaves (rhombus) of two progenies of T. cacao exposed to increasing Pb doses.CCN-10 x SCA-6 (A,C,E e G) and Catongo (B,D,F e H). Mean values of nine replicates (± SE). The absence of error bars indicates that the size of the error does not exceed the size of the symbol. The equations of regression curves were: Cu—CCN-10 x SCA-6: ŷ = 5.43 for leaf, ŷ = 8.65–0.278x (R2 = 0.51) for stem, ŷ = 8.88–0.2753*x (R2 = 0.74) for root. Catongo: ŷ = 4.11 for leaf, ŷ = 6.57 for stem, ŷ = 3.03 for root. Fe—CCN-10 x SCA-6: ŷ = 72.07 for leaf, ŷ = 40.86 for stem, ŷ = 118.10 + 24.97*x (R2 = 0.94) for root. Catongo: ŷ = 76.21 for leaf, ŷ = 40.36 for stem, ŷ = 138.90 + 25.49*x (R2 = 0.93) for root. Mn—CCN-10 x SCA-6: ŷ = 563.1 for leaf, ŷ = 173.5 for stem, ŷ = 84.1 for root. Catongo: ŷ = 1928.84 for leaf, ŷ = 295.4 for stem, ŷ = 72.52 for root. Zn—CCN-10 x SCA-6: ŷ = 44.5 for leaf, ŷ = 74.54 for stem, ŷ = 30.35 for root. Catongo: ŷ = 54.51 for leaf, ŷ = 77.43 for stem, ŷ = 28.51 for root.

Mentions: There was a linear decrease in the concentration of Cu in the root and stem of the CCN-10 x SCA-6 progeny (Fig 10A). In contrast, the concentration of Fe increased 0.2 times in the roots of the CCN-10 x SCV-6 and Catongo progenies (Fig 10C and 10D). Furthermore, the concentration of K increased 0.1 times in the stem and leaf of the CCN-10 x SCA-6 progeny (Fig 9E, S7 Table), while for the Catongo progeny there was a linear decrease of 0.2 times for the concentration of K in the leaves (Fig 9F, S7 Table). However, there were no changes in Zn, Mn, Mg and Ca concentrations in the different organs of the T. cacao progenies (Figs 10E–10L and 9A–9D).


Molecular, Biochemical and Ultrastructural Changes Induced by Pb Toxicity in Seedlings of Theobroma cacao L.

Reis GS, de Almeida AA, de Almeida NM, de Castro AV, Mangabeira PA, Pirovani CP - PLoS ONE (2015)

Accumulation of mineral micronutrients (Cu, Fe, Mn and Zn) in roots (triangle), stem (circle) and leaves (rhombus) of two progenies of T. cacao exposed to increasing Pb doses.CCN-10 x SCA-6 (A,C,E e G) and Catongo (B,D,F e H). Mean values of nine replicates (± SE). The absence of error bars indicates that the size of the error does not exceed the size of the symbol. The equations of regression curves were: Cu—CCN-10 x SCA-6: ŷ = 5.43 for leaf, ŷ = 8.65–0.278x (R2 = 0.51) for stem, ŷ = 8.88–0.2753*x (R2 = 0.74) for root. Catongo: ŷ = 4.11 for leaf, ŷ = 6.57 for stem, ŷ = 3.03 for root. Fe—CCN-10 x SCA-6: ŷ = 72.07 for leaf, ŷ = 40.86 for stem, ŷ = 118.10 + 24.97*x (R2 = 0.94) for root. Catongo: ŷ = 76.21 for leaf, ŷ = 40.36 for stem, ŷ = 138.90 + 25.49*x (R2 = 0.93) for root. Mn—CCN-10 x SCA-6: ŷ = 563.1 for leaf, ŷ = 173.5 for stem, ŷ = 84.1 for root. Catongo: ŷ = 1928.84 for leaf, ŷ = 295.4 for stem, ŷ = 72.52 for root. Zn—CCN-10 x SCA-6: ŷ = 44.5 for leaf, ŷ = 74.54 for stem, ŷ = 30.35 for root. Catongo: ŷ = 54.51 for leaf, ŷ = 77.43 for stem, ŷ = 28.51 for root.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4493102&req=5

pone.0129696.g010: Accumulation of mineral micronutrients (Cu, Fe, Mn and Zn) in roots (triangle), stem (circle) and leaves (rhombus) of two progenies of T. cacao exposed to increasing Pb doses.CCN-10 x SCA-6 (A,C,E e G) and Catongo (B,D,F e H). Mean values of nine replicates (± SE). The absence of error bars indicates that the size of the error does not exceed the size of the symbol. The equations of regression curves were: Cu—CCN-10 x SCA-6: ŷ = 5.43 for leaf, ŷ = 8.65–0.278x (R2 = 0.51) for stem, ŷ = 8.88–0.2753*x (R2 = 0.74) for root. Catongo: ŷ = 4.11 for leaf, ŷ = 6.57 for stem, ŷ = 3.03 for root. Fe—CCN-10 x SCA-6: ŷ = 72.07 for leaf, ŷ = 40.86 for stem, ŷ = 118.10 + 24.97*x (R2 = 0.94) for root. Catongo: ŷ = 76.21 for leaf, ŷ = 40.36 for stem, ŷ = 138.90 + 25.49*x (R2 = 0.93) for root. Mn—CCN-10 x SCA-6: ŷ = 563.1 for leaf, ŷ = 173.5 for stem, ŷ = 84.1 for root. Catongo: ŷ = 1928.84 for leaf, ŷ = 295.4 for stem, ŷ = 72.52 for root. Zn—CCN-10 x SCA-6: ŷ = 44.5 for leaf, ŷ = 74.54 for stem, ŷ = 30.35 for root. Catongo: ŷ = 54.51 for leaf, ŷ = 77.43 for stem, ŷ = 28.51 for root.
Mentions: There was a linear decrease in the concentration of Cu in the root and stem of the CCN-10 x SCA-6 progeny (Fig 10A). In contrast, the concentration of Fe increased 0.2 times in the roots of the CCN-10 x SCV-6 and Catongo progenies (Fig 10C and 10D). Furthermore, the concentration of K increased 0.1 times in the stem and leaf of the CCN-10 x SCA-6 progeny (Fig 9E, S7 Table), while for the Catongo progeny there was a linear decrease of 0.2 times for the concentration of K in the leaves (Fig 9F, S7 Table). However, there were no changes in Zn, Mn, Mg and Ca concentrations in the different organs of the T. cacao progenies (Figs 10E–10L and 9A–9D).

Bottom Line: The activity of guaiacol peroxidases and the expression of genes associated to synthetase of phytochelatin, SODcyt and PER increased in response to Pb.The progeny of CCN-10 x SCA-6 was more tolerant to Pb stress when compared to Catongo, since: (i) it accumulated more Pb in the roots, preventing its translocation to the shoot; (ii) it presented higher activity of peroxidases in the roots, which are enzymes involved in the elimination of excess of reactive oxygen species; and (iii) increased expression of the gene in the phytochelatin biosynthesis route.The results of the proteomic analysis were of paramount importance to differentiate the defense mechanisms used by both progenies of T. cacao.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, State University of Santa Cruz, Campus Soane Nazaré de Andrade, Rodovia Jorge Amado, km 16, 45662-900, Ilhéus, BA, Brazil.

ABSTRACT
Pb is a metal which is highly toxic to plants and animals, including humans. High concentrations of Pb have been observed in beans of T. cacao, as well as in its products. In this work, we evaluated the molecular, biochemical, and ultrastructural alterations in mature leaves and primary roots of seedlings of two progenies of T. cacao, obtained from seed germination in different concentrations of Pb (0, 0.05, 0.1, 0.2, 0.4, 0.8 g L(-1)), in the form of Pb(NO3)2. The progenies resulted from self-fertilization of Catongo and a cross of CCN-10 x SCA-6. The Pb, supplied via seminal, caused alterations in the ultrastructures of the mesophyll cells and in the amount of starch grains in the chloroplasts. The dosage of substances reactive to thiobarbituric acid showed that Pb induced lipid peroxidation. The activity of guaiacol peroxidases and the expression of genes associated to synthetase of phytochelatin, SODcyt and PER increased in response to Pb. In addition, there was alteration in the expression of stress-related proteins. The progeny of CCN-10 x SCA-6 was more tolerant to Pb stress when compared to Catongo, since: (i) it accumulated more Pb in the roots, preventing its translocation to the shoot; (ii) it presented higher activity of peroxidases in the roots, which are enzymes involved in the elimination of excess of reactive oxygen species; and (iii) increased expression of the gene in the phytochelatin biosynthesis route. The results of the proteomic analysis were of paramount importance to differentiate the defense mechanisms used by both progenies of T. cacao.

No MeSH data available.


Related in: MedlinePlus