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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

Guaiacol peroxidase activity (POD).Leaves (A) and roots (B) of two progenies of T. cacao exposed to increasing doses of Pb. The statistical significance interprogenies was obtained by t-test. (*) p<0.05; (**) p<0.01; (***) p<0.001; (ns) not significant. Mean values intraprogenies followed by the same lowercase letters do not differ by Tukey test (p<0.05). Mean values of four replicates (± SE).
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pone.0129696.g006: Guaiacol peroxidase activity (POD).Leaves (A) and roots (B) of two progenies of T. cacao exposed to increasing doses of Pb. The statistical significance interprogenies was obtained by t-test. (*) p<0.05; (**) p<0.01; (***) p<0.001; (ns) not significant. Mean values intraprogenies followed by the same lowercase letters do not differ by Tukey test (p<0.05). Mean values of four replicates (± SE).

Mentions: The susceptible progeny presented a significant increment (p<0.05) in the leaves of 1.6, 4.1, 3.6, 3.9, and 5.5 times for the doses corresponding to 0.05, 0.1, 0.2, 0.4, and 0.8 g Pb L-1, respectively, in comparison to the control (Fig 6A, S2 Table). Already resistant progeny presented a significant increase of 1.2 times for the GPX activity only for the dose of 0.2 g Pb L-1. In the roots of the two progenies, there was an increase of GPX activity parallel to the increase in doses of Pb (Fig 6B). The susceptible progeny presented an increase of 0.5, 1.9, 2.0, 1.7, and 0.4 times in the GPX activity for the doses of 0.05, 0.1, 0.2, 0.4, and 0.8 g Pb L-1, respectively, in comparison to the control. Regarding the resistant progeny, there was an increase of 0.3; 0.6; 0.9, 0.3 and 1.1 times for the doses of 0.05, 0.1, 0.2, 0.4, and 0.8 g Pb L-1, respectively, in comparison to the control.


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)

Guaiacol peroxidase activity (POD).Leaves (A) and roots (B) of two progenies of T. cacao exposed to increasing doses of Pb. The statistical significance interprogenies was obtained by t-test. (*) p<0.05; (**) p<0.01; (***) p<0.001; (ns) not significant. Mean values intraprogenies followed by the same lowercase letters do not differ by Tukey test (p<0.05). Mean values of four replicates (± SE).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0129696.g006: Guaiacol peroxidase activity (POD).Leaves (A) and roots (B) of two progenies of T. cacao exposed to increasing doses of Pb. The statistical significance interprogenies was obtained by t-test. (*) p<0.05; (**) p<0.01; (***) p<0.001; (ns) not significant. Mean values intraprogenies followed by the same lowercase letters do not differ by Tukey test (p<0.05). Mean values of four replicates (± SE).
Mentions: The susceptible progeny presented a significant increment (p<0.05) in the leaves of 1.6, 4.1, 3.6, 3.9, and 5.5 times for the doses corresponding to 0.05, 0.1, 0.2, 0.4, and 0.8 g Pb L-1, respectively, in comparison to the control (Fig 6A, S2 Table). Already resistant progeny presented a significant increase of 1.2 times for the GPX activity only for the dose of 0.2 g Pb L-1. In the roots of the two progenies, there was an increase of GPX activity parallel to the increase in doses of Pb (Fig 6B). The susceptible progeny presented an increase of 0.5, 1.9, 2.0, 1.7, and 0.4 times in the GPX activity for the doses of 0.05, 0.1, 0.2, 0.4, and 0.8 g Pb L-1, respectively, in comparison to the control. Regarding the resistant progeny, there was an increase of 0.3; 0.6; 0.9, 0.3 and 1.1 times for the doses of 0.05, 0.1, 0.2, 0.4, and 0.8 g Pb L-1, respectively, in comparison to the control.

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