Presence of state transitions in the cryptophyte alga Guillardia theta
2015 (English)In: Journal of Experimental Botany, ISSN 0022-0957, E-ISSN 1460-2431, Vol. 66, no 20, 6461-6470 p.Article in journal (Refereed) Published
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 photosys-tems, meanwhile the latter by dissipating excessive excitation inside the antennae. In the present study, these mecha-nisms 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. thetaare 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.
Place, publisher, year, edition, pages
Oxford University Press, 2015. Vol. 66, no 20, 6461-6470 p.
Blue/low light adaptation, chlorophyll a/c antenna, cryptophytes, growth stage, non-photochemical quenching, state transitions
IdentifiersURN: urn:nbn:se:umu:diva-109165DOI: 10.1093/jxb/erv362ISI: 000366490000028PubMedID: 26254328OAI: oai:DiVA.org:umu-109165DiVA: diva2:855640