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Kinetic Analysis of Zinc/Cadmium Reciprocal Competitions Suggests a Possible Zn-Insensitive Pathway for Root-to-Shoot Cadmium Translocation in Rice

BACKGROUND: Among cereals, rice has a genetic propensity to accumulate high levels of cadmium (Cd) in grains. Xylem-mediated root-to-shoot translocation rather than root uptake has been suggested as the main physiological factor accounting for the genotypic variation observed in Cd accumulation in s...

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Autores principales: Fontanili, Laura, Lancilli, Clarissa, Suzui, Nobuo, Dendena, Bianca, Yin, Yong-Gen, Ferri, Alessandro, Ishii, Satomi, Kawachi, Naoki, Lucchini, Giorgio, Fujimaki, Shu, Sacchi, Gian Attilio, Nocito, Fabio Francesco
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer US 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4828370/
https://www.ncbi.nlm.nih.gov/pubmed/27068924
http://dx.doi.org/10.1186/s12284-016-0088-3
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author Fontanili, Laura
Lancilli, Clarissa
Suzui, Nobuo
Dendena, Bianca
Yin, Yong-Gen
Ferri, Alessandro
Ishii, Satomi
Kawachi, Naoki
Lucchini, Giorgio
Fujimaki, Shu
Sacchi, Gian Attilio
Nocito, Fabio Francesco
author_facet Fontanili, Laura
Lancilli, Clarissa
Suzui, Nobuo
Dendena, Bianca
Yin, Yong-Gen
Ferri, Alessandro
Ishii, Satomi
Kawachi, Naoki
Lucchini, Giorgio
Fujimaki, Shu
Sacchi, Gian Attilio
Nocito, Fabio Francesco
author_sort Fontanili, Laura
collection PubMed
description BACKGROUND: Among cereals, rice has a genetic propensity to accumulate high levels of cadmium (Cd) in grains. Xylem-mediated root-to-shoot translocation rather than root uptake has been suggested as the main physiological factor accounting for the genotypic variation observed in Cd accumulation in shoots and grains. Several evidence indicate OsHMA2 – a putative zinc (Zn) transporter – as the main candidate protein that could be involved in mediating Cd- and Zn-xylem loading in rice. However, the specific interactions between Zn and Cd in rice often appear anomalous if compared to those observed in other staple crops, suggesting that root-to-shoot Cd translocation process could be more complex than previously thought. In this study we performed a complete set of competition experiments with Zn and Cd in order to analyze their possible interactions and reciprocal effects at the root-to-shoot translocation level. RESULTS: The competition analysis revealed the lack of a full reciprocity when considering the effect of Cd on Zn accumulation, and vice versa, since the accumulation of Zn in the shoots was progressively inhibited by Cd increases, whereas that of Cd was only partially impaired by Zn. Such behaviors were probably dependent on Cd-xylem loading mechanisms, as suggested by: i) the analysis of Zn and Cd content in the xylem sap performed in relation to the concentration of the two metals in the mobile fractions of the roots; ii) the analysis of the systemic movement of (107)Cd in short term experiments performed using a positron-emitting tracer imaging system (PETIS). CONCLUSIONS: Our results suggest that at least two pathways may mediate root-to-shoot Cd translocation in rice. The former could involve OsHMA2 as Zn(2+)/Cd(2+) xylem loader, whereas the latter appears to involve a Zn-insensitive system that still needs to be identified. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12284-016-0088-3) contains supplementary material, which is available to authorized users.
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spelling pubmed-48283702016-04-21 Kinetic Analysis of Zinc/Cadmium Reciprocal Competitions Suggests a Possible Zn-Insensitive Pathway for Root-to-Shoot Cadmium Translocation in Rice Fontanili, Laura Lancilli, Clarissa Suzui, Nobuo Dendena, Bianca Yin, Yong-Gen Ferri, Alessandro Ishii, Satomi Kawachi, Naoki Lucchini, Giorgio Fujimaki, Shu Sacchi, Gian Attilio Nocito, Fabio Francesco Rice (N Y) Original Article BACKGROUND: Among cereals, rice has a genetic propensity to accumulate high levels of cadmium (Cd) in grains. Xylem-mediated root-to-shoot translocation rather than root uptake has been suggested as the main physiological factor accounting for the genotypic variation observed in Cd accumulation in shoots and grains. Several evidence indicate OsHMA2 – a putative zinc (Zn) transporter – as the main candidate protein that could be involved in mediating Cd- and Zn-xylem loading in rice. However, the specific interactions between Zn and Cd in rice often appear anomalous if compared to those observed in other staple crops, suggesting that root-to-shoot Cd translocation process could be more complex than previously thought. In this study we performed a complete set of competition experiments with Zn and Cd in order to analyze their possible interactions and reciprocal effects at the root-to-shoot translocation level. RESULTS: The competition analysis revealed the lack of a full reciprocity when considering the effect of Cd on Zn accumulation, and vice versa, since the accumulation of Zn in the shoots was progressively inhibited by Cd increases, whereas that of Cd was only partially impaired by Zn. Such behaviors were probably dependent on Cd-xylem loading mechanisms, as suggested by: i) the analysis of Zn and Cd content in the xylem sap performed in relation to the concentration of the two metals in the mobile fractions of the roots; ii) the analysis of the systemic movement of (107)Cd in short term experiments performed using a positron-emitting tracer imaging system (PETIS). CONCLUSIONS: Our results suggest that at least two pathways may mediate root-to-shoot Cd translocation in rice. The former could involve OsHMA2 as Zn(2+)/Cd(2+) xylem loader, whereas the latter appears to involve a Zn-insensitive system that still needs to be identified. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12284-016-0088-3) contains supplementary material, which is available to authorized users. Springer US 2016-04-12 /pmc/articles/PMC4828370/ /pubmed/27068924 http://dx.doi.org/10.1186/s12284-016-0088-3 Text en © Fontanili et al. 2016 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Original Article
Fontanili, Laura
Lancilli, Clarissa
Suzui, Nobuo
Dendena, Bianca
Yin, Yong-Gen
Ferri, Alessandro
Ishii, Satomi
Kawachi, Naoki
Lucchini, Giorgio
Fujimaki, Shu
Sacchi, Gian Attilio
Nocito, Fabio Francesco
Kinetic Analysis of Zinc/Cadmium Reciprocal Competitions Suggests a Possible Zn-Insensitive Pathway for Root-to-Shoot Cadmium Translocation in Rice
title Kinetic Analysis of Zinc/Cadmium Reciprocal Competitions Suggests a Possible Zn-Insensitive Pathway for Root-to-Shoot Cadmium Translocation in Rice
title_full Kinetic Analysis of Zinc/Cadmium Reciprocal Competitions Suggests a Possible Zn-Insensitive Pathway for Root-to-Shoot Cadmium Translocation in Rice
title_fullStr Kinetic Analysis of Zinc/Cadmium Reciprocal Competitions Suggests a Possible Zn-Insensitive Pathway for Root-to-Shoot Cadmium Translocation in Rice
title_full_unstemmed Kinetic Analysis of Zinc/Cadmium Reciprocal Competitions Suggests a Possible Zn-Insensitive Pathway for Root-to-Shoot Cadmium Translocation in Rice
title_short Kinetic Analysis of Zinc/Cadmium Reciprocal Competitions Suggests a Possible Zn-Insensitive Pathway for Root-to-Shoot Cadmium Translocation in Rice
title_sort kinetic analysis of zinc/cadmium reciprocal competitions suggests a possible zn-insensitive pathway for root-to-shoot cadmium translocation in rice
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4828370/
https://www.ncbi.nlm.nih.gov/pubmed/27068924
http://dx.doi.org/10.1186/s12284-016-0088-3
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