Presence of state transitions in the cryptophyte alga Guillardia theta

Plants and algae have developed various regulatory mechanisms for optimal delivery of excitation energy to the photosystems even during fluctuating light conditions; these include state transitions as well as non-photochemical quenching. The former process maintains the balance by redistributing ant...

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Bibliographic Details
Published in:Journal of experimental botany 2015-10, Vol.66 (20), p.6461-6470
Main Authors: Cheregi, Otilia, Kotabová, Eva, Prášil, Ondřej, Schröder, Wolfgang P., Kaňa, Radek, Funk, Christiane
Format: Article
Language:English
Subjects:
Blue/low light adaptation
Carbon Dioxide - metabolism
chlorophyll a/c antenna
Cryptophyta - growth & development
Cryptophyta - physiology
cryptophytes
Electron Transport
growth stage
Light
non-photochemical quenching
Photochemical Processes
Photosynthesis
RESEARCH PAPER
state transitions
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Summary:Plants and algae have developed various regulatory mechanisms for optimal delivery of excitation energy to the photosystems even during fluctuating light conditions; these include state transitions as well as non-photochemical quenching. The former process maintains the balance by redistributing antennae excitation between the photosystems, meanwhile the latter by dissipating excessive excitation inside the antennae. In the present study, these mechanisms have been analysed in the cryptophyte alga Guillardia theta. Photoprotective non-photochemical quenching was observed in cultures only after they had entered the stationary growth phase. These cells displayed a diminished overall photosynthetic efficiency, measured as CO₂ assimilation rate and electron transport rate. However, in the logarithmic growth phase G. theta cells redistributed excitation energy via a mechanism similar to state transitions. These state transitions were triggered by blue light absorbed by the membrane integrated chlorophyll a/c antennae, and green light absorbed by the lumenal biliproteins was ineffective. It is proposed that state transitions in G. theta are induced by small re-arrangements of the intrinsic antennae proteins, resulting in their coupling/uncoupling to the photosystems in state 1 or state 2, respectively. G. theta therefore represents a chromalveolate algae able to perform state transitions.
ISSN:0022-0957
1460-2431
1460-2431
DOI:10.1093/jxb/erv362