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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 Pb in roots (triangle), stem (circle) and leaves (rhombus) of two progenies of T. cacao submitted to increasing of Pb doses.CCN-10 x SCA-6 (A) and Catongo (B). Mean values of nine replicates (± SE). The equations of the regression curves were: CCN-10 x SCA-6: ŷ = - 3.99 + 2.46*x (R² = 0.92) for leaf, ŷ = - 9.02 + 5.68*x, (R² = 0.92) for stem, ŷ = -17.58 + 11.74*x (R² = 0.87) for root. Catongo: y = - 3,047 + 2.49*x (R² = 0.96) for leaf, ŷ = -10.43 + 10.43*x– 0.88 x2 (R² = 0.94) for stem, ŷ = - 0.92 + 5.68 ln*(x) (R² = 0.93) for root.
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pone.0129696.g008: Accumulation of Pb in roots (triangle), stem (circle) and leaves (rhombus) of two progenies of T. cacao submitted to increasing of Pb doses.CCN-10 x SCA-6 (A) and Catongo (B). Mean values of nine replicates (± SE). The equations of the regression curves were: CCN-10 x SCA-6: ŷ = - 3.99 + 2.46*x (R² = 0.92) for leaf, ŷ = - 9.02 + 5.68*x, (R² = 0.92) for stem, ŷ = -17.58 + 11.74*x (R² = 0.87) for root. Catongo: y = - 3,047 + 2.49*x (R² = 0.96) for leaf, ŷ = -10.43 + 10.43*x– 0.88 x2 (R² = 0.94) for stem, ŷ = - 0.92 + 5.68 ln*(x) (R² = 0.93) for root.

Mentions: Pb was detected in the roots, stems and leaves of the susceptible and resistant progenies. The Pb concentrations found in the different organs were proportional to the increase of the doses of Pb supplied via seminal for both progenies (Fig 8A and 8B). The highest accumulation of Pb was evidenced in the roots of the resistant progeny at 60 days after emergence (DAE) (Fig 8B, S6 Table). The roots, stems and leaves of the susceptible and resistant progenies accumulated 24.7, 19.9, and 13.1 mg Pb kg-1 DW and 52.1, 25.7, and 11.0 mg Pb kg-1 DW respectively, in the dose corresponding to 0.8 g Pb L-1.


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 Pb in roots (triangle), stem (circle) and leaves (rhombus) of two progenies of T. cacao submitted to increasing of Pb doses.CCN-10 x SCA-6 (A) and Catongo (B). Mean values of nine replicates (± SE). The equations of the regression curves were: CCN-10 x SCA-6: ŷ = - 3.99 + 2.46*x (R² = 0.92) for leaf, ŷ = - 9.02 + 5.68*x, (R² = 0.92) for stem, ŷ = -17.58 + 11.74*x (R² = 0.87) for root. Catongo: y = - 3,047 + 2.49*x (R² = 0.96) for leaf, ŷ = -10.43 + 10.43*x– 0.88 x2 (R² = 0.94) for stem, ŷ = - 0.92 + 5.68 ln*(x) (R² = 0.93) for root.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493102&req=5

pone.0129696.g008: Accumulation of Pb in roots (triangle), stem (circle) and leaves (rhombus) of two progenies of T. cacao submitted to increasing of Pb doses.CCN-10 x SCA-6 (A) and Catongo (B). Mean values of nine replicates (± SE). The equations of the regression curves were: CCN-10 x SCA-6: ŷ = - 3.99 + 2.46*x (R² = 0.92) for leaf, ŷ = - 9.02 + 5.68*x, (R² = 0.92) for stem, ŷ = -17.58 + 11.74*x (R² = 0.87) for root. Catongo: y = - 3,047 + 2.49*x (R² = 0.96) for leaf, ŷ = -10.43 + 10.43*x– 0.88 x2 (R² = 0.94) for stem, ŷ = - 0.92 + 5.68 ln*(x) (R² = 0.93) for root.
Mentions: Pb was detected in the roots, stems and leaves of the susceptible and resistant progenies. The Pb concentrations found in the different organs were proportional to the increase of the doses of Pb supplied via seminal for both progenies (Fig 8A and 8B). The highest accumulation of Pb was evidenced in the roots of the resistant progeny at 60 days after emergence (DAE) (Fig 8B, S6 Table). The roots, stems and leaves of the susceptible and resistant progenies accumulated 24.7, 19.9, and 13.1 mg Pb kg-1 DW and 52.1, 25.7, and 11.0 mg Pb kg-1 DW respectively, in the dose corresponding to 0.8 g Pb L-1.

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