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A pea mutant ( costata ) expressing higher activity in thylakoid membrane‐bound carbonic anhydrase altersPSII downregulation mechanisms
Author(s) -
Lazova G.,
Naidenova N.,
Ignatova L.,
Stefanov D.
Publication year - 2009
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2009.04.003
Subject(s) - thylakoid , photosynthesis , chlorophyll fluorescence , pisum , photosystem ii , downregulation and upregulation , mutant , carbonic anhydrase , biology , electron transport chain , biochemistry , chlorophyll , sativum , biophysics , chloroplast , chemistry , enzyme , botany , gene
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 O 2 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 ( F v / F m ) 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.