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INORGANIC CARBON REPLETION DISRUPTS PHOTOSYNTHETIC ACCLIMATION TO LOW TEMPERATURE IN THE CYANOBACTERIUM SYNECHOCOCCUS ELONGATUS 1
Author(s) -
Burns Robert A.,
MacDonald C. Danielle,
McGinn Patrick J.,
Campbell Douglas. A.
Publication year - 2005
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.2005.04101.x
Subject(s) - acclimatization , photosynthesis , biology , cyanobacteria , synechococcus , phycocyanin , photosystem ii , botany , senescence , chloroplast , biophysics , biochemistry , microbiology and biotechnology , gene , genetics , bacteria
Acclimation of cyanobacteria to ambient fluctuations in inorganic carbon (Ci) and temperature requires reorganization of the major protein complexes involved in photosynthesis. We grew cultures of the picoplanktonic cyanobacterium Synechococcus elongatus Naegeli across most of its range of tolerable temperatures from 23 to 35°C at both low (<0.1 mM) and high Ci (approximately 4 mM). Over that range of temperatures, the chl‐based doubling time did not differ between low and high Ci grown cells but did increase with decreasing temperature. Cells grown at 23°C high Ci showed an elongated morphology, which was not present in 23°C low Ci cells nor at 35°C high and low Ci. Furthermore, 23°C high Ci cells showed premature senescence and death compared with all other treatments. Phycocyanin per cell was greater in high Ci grown cells at all temperatures but showed a characteristic decrease with decreasing temperature. Functional PSII determination showed that 23°C high Ci cells had 1.5 × 10 5 PSII·cell –1 compared with only 6.9 × 10 4 PSII·cell –1 for 23°C low Ci. The 35°C high and low Ci cells had 7.7 × 10 4 and 6.4 × 10 4 PSII·cell –1 , respectively. These data were supported by immunoblot determinations of PsbA content·cell –1 . As a result of their high PSII·cell –1 , 23°C high Ci cells generated more reductant from PSII than could be accommodated by downstream assimilative metabolism, resulting in early senescence and death of 23°C high Ci cells, probably as a result of the generation of reactive byproducts of electron transport.