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A pea mutant (costata) expressing higher activity in thylakoid membrane-bound carbonic anhydrase altersPSII downregulation mechanisms

Authors

  • G. Lazova,

    Corresponding author
    1. Institute of Plant Physiology “M. Popov”, Sofia, Bulgarian Academy of Sciences, Acad.G.Bonchev Str., Bl21, 1113 Sofia, Bulgaria
      Tel.: +359 2979 2635; fax: +359 273 9952. E-mail addresses: lazova@bio21.bas.bg
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  • N. Naidenova,

    Corresponding author
    1. Institute of Genetics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
      E-mail addresses: genetika@bas.bg
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  • L. Ignatova,

    Corresponding author
    1. Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya, 2, Pushchino Moskow Region 142290, Russian Federation
      E-mail addresses: ivabor@issp.serpukhov.su
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  • D. Stefanov

    Corresponding author
    1. Institute of Plant Physiology “M. Popov”, Sofia, Bulgarian Academy of Sciences, Acad.G.Bonchev Str., Bl21, 1113 Sofia, Bulgaria
      E-mail addresses: detelin@bio21.bas.bg
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Tel.: +359 2979 2635; fax: +359 273 9952. E-mail addresses: lazova@bio21.bas.bg

E-mail addresses: genetika@bas.bg

E-mail addresses: ivabor@issp.serpukhov.su

E-mail addresses: detelin@bio21.bas.bg

Abstract

The interaction between photosynthetic electron transport and the activities of the thylakoid associated carbonic anhydrase (tCA), estimated as combined tCA activity in pea plants (Pisum sativum L. Borek cv., WT) and mutant form (costata 2/125) that differ in chlorophyll content have been compared. Chlorophyll a fluorescence changes after the inhibition of tCA by ethoxyzolamide (EZ), estimating possible role of tCA in PSII downregulation were investigated. Costata expresses higher tCA activity and higher O2 evolution in comparison to WT. Inhibition of tCA by EZ decreased effective PSII photochemistry that coincided with an enhancement in thermal dissipation, while maximal PSII quantum yield (Fv/Fm) did not significantly change. Ethoxyzolamide induced changes in fluorescence parameters that were more strongly expressed in costata 2/125. The results show that tCA is involved in the regulation of the proton gradient across thylakoid membranes and thus limits PSII downregulation.

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