Identification of a homolog of Arabidopsis DSP4 (SEX4) in chestnut: its induction and accumulation in stem amyloplasts during winter or in response to the cold

Authors

  • MARTA BERROCAL-LOBO,

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    • These authors contributed equally to the article.

  • CRISTIAN IBAÑEZ,

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    • These authors contributed equally to the article.

    • Present address: Universidad de La Serena, Facultad de Ciencias, Departamento de Biología, Campus Andrés Bello, Avenida Raúl Bitrán s/n (051) 204309, Chile.

  • PALOMA ACEBO,

    1. Centro de Biotecnología y Genómica de Plantas UPM/INIA, Departamento de Biotecnología, E. T. S. Ingenieros de Montes, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, E-28223 Madrid, Spain
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  • ALBERTO RAMOS,

    1. Centro de Biotecnología y Genómica de Plantas UPM/INIA, Departamento de Biotecnología, E. T. S. Ingenieros de Montes, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, E-28223 Madrid, Spain
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  • ESTEFANIA PEREZ-SOLIS,

    1. Centro de Biotecnología y Genómica de Plantas UPM/INIA, Departamento de Biotecnología, E. T. S. Ingenieros de Montes, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, E-28223 Madrid, Spain
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  • CARMEN COLLADA,

    1. Centro de Biotecnología y Genómica de Plantas UPM/INIA, Departamento de Biotecnología, E. T. S. Ingenieros de Montes, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, E-28223 Madrid, Spain
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  • ROSA CASADO,

    1. Centro de Biotecnología y Genómica de Plantas UPM/INIA, Departamento de Biotecnología, E. T. S. Ingenieros de Montes, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, E-28223 Madrid, Spain
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  • CIPRIANO ARAGONCILLO,

    1. Centro de Biotecnología y Genómica de Plantas UPM/INIA, Departamento de Biotecnología, E. T. S. Ingenieros de Montes, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, E-28223 Madrid, Spain
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  • ISABEL ALLONA

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I. Allona. Fax: +34 917157721; e-mail: isabel.allona@upm.es

ABSTRACT

Oligosaccharide synthesis is an important cryoprotection strategy used by woody plants during winter dormancy. At the onset of autumn, starch stored in the stem and buds is broken down in response to the shorter days and lower temperatures resulting in the buildup of oligosaccharides. Given that the enzyme DSP4 is necessary for diurnal starch degradation in Arabidopsis leaves, this study was designed to address the role of DSP4 in this seasonal process in Castanea sativa Mill. The expression pattern of the CsDSP4 gene in cells of the chestnut stem was found to parallel starch catabolism. In this organ, DSP4 protein levels started to rise at the start of autumn and elevated levels persisted until the onset of spring. In addition, exposure of chestnut plantlets to 4 °C induced the expression of the CsDSP4 gene. In dormant trees or cold-stressed plantlets, the CsDSP4 protein was immunolocalized both in the amyloplast stroma and nucleus of stem cells, whereas in the conditions of vegetative growth, immunofluorescence was only detected in the nucleus. The studies indicate a potential role for DSP4 in starch degradation and cold acclimation following low temperature exposure during activity–dormancy transition.

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