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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

Amount of gene transcripts of the biosynthetic pathway of phytochelatins synthase (PCs); cytoplasmic superoxide dismutase (SODCyt) and peroxidase (PER-1) in leaves and roots of T. cacao progenies.Catongo (A), (C) and (E), and CCN-10 x SCA-6 (B), (D) and (F) exposed to increasing of Pb doses. The mRNA levels were quantified by quantitative real-time PCR. The mRNA levels were normalized in respect to tubulin, and are expressed relatively to those of control plants that were given a value of 1. Mean values of Intraprogenies followed by the same lowercase letters do not differ by Tukey test (p <0.05). Mean values of six replicates (± SE).
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pone.0129696.g007: Amount of gene transcripts of the biosynthetic pathway of phytochelatins synthase (PCs); cytoplasmic superoxide dismutase (SODCyt) and peroxidase (PER-1) in leaves and roots of T. cacao progenies.Catongo (A), (C) and (E), and CCN-10 x SCA-6 (B), (D) and (F) exposed to increasing of Pb doses. The mRNA levels were quantified by quantitative real-time PCR. The mRNA levels were normalized in respect to tubulin, and are expressed relatively to those of control plants that were given a value of 1. Mean values of Intraprogenies followed by the same lowercase letters do not differ by Tukey test (p <0.05). Mean values of six replicates (± SE).

Mentions: The transcripts from the gene phytochelatin synthase (PCS) were not detected in leaves in both progeny. In the roots, the susceptible progeny presented an increase in expression of this gene of about 0.8 times for the dose of 0.8 g Pb L-1 (Fig 7A, S5 Table). In contrast, in the resistant progeny, there was an increase in the expression of 0.7 and 0.2 times for the doses of 0.2 and 0.8 g Pb L-1, respectively (Fig 7B).


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)

Amount of gene transcripts of the biosynthetic pathway of phytochelatins synthase (PCs); cytoplasmic superoxide dismutase (SODCyt) and peroxidase (PER-1) in leaves and roots of T. cacao progenies.Catongo (A), (C) and (E), and CCN-10 x SCA-6 (B), (D) and (F) exposed to increasing of Pb doses. The mRNA levels were quantified by quantitative real-time PCR. The mRNA levels were normalized in respect to tubulin, and are expressed relatively to those of control plants that were given a value of 1. Mean values of Intraprogenies followed by the same lowercase letters do not differ by Tukey test (p <0.05). Mean values of six replicates (± SE).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0129696.g007: Amount of gene transcripts of the biosynthetic pathway of phytochelatins synthase (PCs); cytoplasmic superoxide dismutase (SODCyt) and peroxidase (PER-1) in leaves and roots of T. cacao progenies.Catongo (A), (C) and (E), and CCN-10 x SCA-6 (B), (D) and (F) exposed to increasing of Pb doses. The mRNA levels were quantified by quantitative real-time PCR. The mRNA levels were normalized in respect to tubulin, and are expressed relatively to those of control plants that were given a value of 1. Mean values of Intraprogenies followed by the same lowercase letters do not differ by Tukey test (p <0.05). Mean values of six replicates (± SE).
Mentions: The transcripts from the gene phytochelatin synthase (PCS) were not detected in leaves in both progeny. In the roots, the susceptible progeny presented an increase in expression of this gene of about 0.8 times for the dose of 0.8 g Pb L-1 (Fig 7A, S5 Table). In contrast, in the resistant progeny, there was an increase in the expression of 0.7 and 0.2 times for the doses of 0.2 and 0.8 g Pb L-1, respectively (Fig 7B).

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