Rubisco specificity factor tends to be larger in plant species from drier habitats and in species with persistent leaves

Authors

  • JERONI GALMÉS,

    1. Laboratori de Fisiologia Vegetal, Grup de Biologia de les Plantes en Condicions Mediterrànies, Universitat de les Illes Balears. Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Balears, Spain and
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  • JAUME FLEXAS,

    Corresponding author
    1. Laboratori de Fisiologia Vegetal, Grup de Biologia de les Plantes en Condicions Mediterrànies, Universitat de les Illes Balears. Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Balears, Spain and
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  • ALFRED J. KEYS,

    1. Crop Performance and Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, U.K.
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  • JOSEP CIFRE,

    1. Laboratori de Fisiologia Vegetal, Grup de Biologia de les Plantes en Condicions Mediterrànies, Universitat de les Illes Balears. Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Balears, Spain and
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  • ROWAN A. C. MITCHELL,

    1. Crop Performance and Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, U.K.
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  • PIPPA J. MADGWICK,

    1. Crop Performance and Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, U.K.
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  • RICHARD P. HASLAM,

    1. Crop Performance and Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, U.K.
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  • HIPÓLITO MEDRANO,

    1. Laboratori de Fisiologia Vegetal, Grup de Biologia de les Plantes en Condicions Mediterrànies, Universitat de les Illes Balears. Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Balears, Spain and
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  • MARTIN A. J. PARRY

    1. Crop Performance and Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, U.K.
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Jaume Flexas. Fax: 34/971/173184; e-mail: jaume.flexas@uib.es

ABSTRACT

The specificity factor of Rubisco is a measure of the relative capacities of the enzyme to catalyse carboxylation and oxygenation of ribulose 1,5-bisphosphate and hence to control the relative rates of photosynthetic carbon assimilation and photorespiration. Specificity factors of purified Rubisco from 24 species of C3 plants found in diverse habitats with a wide range of environmental growth limitations by both water availability and temperature in the Balearic Islands were measured at 25 °C. The results suggest that specificity factors are more dependent on environmental pressure than on phylogenetic factors. Irrespective of phylogenetic relationships, higher specificity factors were found in species characteristically growing in dryer environments and in species that are hemideciduous or evergreen. Effects of temperature on specificity factor of the purified enzyme from 14 species were consistent with the concept that higher specificity factors were associated with an increase in the activation energy for oxygenation compared to carboxylation of the 2,3-enediolate of RuBP to the respective transition state intermediates. The results are discussed in terms of selection pressures leading to the differences in specificity factors and the value of the observations for identifying useful genetic manipulation to change Rubisco polypeptide subunits.

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