H2O2 in plant peroxisomes: an in vivo analysis uncovers a Ca2+-dependent scavenging system

Authors

  • Alex Costa,

    Corresponding author
    1. Dipartimento di Biologia, Università degli Studi di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
      For correspondence (fax +39 049 8276300; e-mail alex.costa@unipd.it).
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  • Ilaria Drago,

    1. Dipartimento di Scienze Biomediche e Istituto di Neuroscienze CNR, Università degli Studi di Padova, Viale G. Colombo 3, 35121 Padova, Italy
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  • Smrutisanjita Behera,

    1. Dipartimento di Biologia, Università degli Studi di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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  • Michela Zottini,

    1. Dipartimento di Biologia, Università degli Studi di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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  • Paola Pizzo,

    1. Dipartimento di Scienze Biomediche e Istituto di Neuroscienze CNR, Università degli Studi di Padova, Viale G. Colombo 3, 35121 Padova, Italy
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  • Julian I. Schroeder,

    1. Division of Biology, Cell and Developmental Biology Section, and Center for Molecular Genetics, University of California San Diego, CA 92093–0116 La Jolla, USA
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  • Tullio Pozzan,

    1. Dipartimento di Scienze Biomediche e Istituto di Neuroscienze CNR, Università degli Studi di Padova, Viale G. Colombo 3, 35121 Padova, Italy
    2. Venetian Institute of Molecular Medicine, Via Orus 2, 35129 Padova, Italy
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  • Fiorella Lo Schiavo

    1. Dipartimento di Biologia, Università degli Studi di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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For correspondence (fax +39 049 8276300; e-mail alex.costa@unipd.it).

Summary

Oxidative stress is a major challenge for all cells living in an oxygen-based world. Among reactive oxygen species, H2O2, is a well known toxic molecule and, nowadays, considered a specific component of several signalling pathways. In order to gain insight into the roles played by H2O2 in plant cells, it is necessary to have a reliable, specific and non-invasive methodology for its in vivo detection. Hence, the genetically encoded H2O2 sensor HyPer was expressed in plant cells in different subcellular compartments such as cytoplasm and peroxisomes. Moreover, with the use of the new green fluorescent protein (GFP)-based Cameleon Ca2+ indicator, D3cpv–KVK–SKL, targeted to peroxisomes, we demonstrated that the induction of cytoplasmic Ca2+ increase is followed by Ca2+ rise in the peroxisomal lumen. The analyses of HyPer fluorescence ratios were performed in leaf peroxisomes of tobacco and pre- and post-bolting Arabidopsis plants. These analyses allowed us to demonstrate that an intraperoxisomal Ca2+ rise in vivo stimulates catalase activity, increasing peroxisomal H2O2 scavenging efficiency.

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