fulltext.study @t Gmail

Photoprotection in the brown alga Macrocystis pyrifera: Evolutionary implications

Paper ID Volume ID Publish Year Pages File Format Full-Text
29646 44425 2011 9 PDF Available
Title
Photoprotection in the brown alga Macrocystis pyrifera: Evolutionary implications
Abstract

The dissipation of energy as heat is essential for photosynthetic organisms to protect themselves against excess light. We compared Photosystem II florescence changes (non-photochemical quenching, NPQ) in the brown alga Macrocystis pyrifera with that of Ficus sp., a higher plant to examine if the mechanism of heat dissipation (energy-dependent quenching, qE) differs between these evolutionary distant groups of phototrophs. We discovered that M. pyrifera had a slower rise of NPQ upon illumination than the Ficus sp. Further, the NPQ relaxation phase that takes place in the first minutes after light to dark transition is absent in this brown alga. We found that the NPQ induction rate in this alga was 1.5 times faster in preilluminated samples than in dark-adapted samples; this was associated with an increase in the rate of accumulation of the carotenoid zeaxanthin. Therefore, we conclude that NPQ in M. pyrifera is associated only with the formation of zeaxanthin. These results indicate that M. pyrifera lacks the fast component of qE that is related to allosteric changes in the light harvesting complexes of Ficus sp., a representative of higher plants. Although the xanthophyll cycle of this brown alga is similar to that of Ficus sp., yet, the transthylakoid proton gradient (ΔpH) does not influence NPQ beyond the activation of the violaxanthin de-epoxidase enzyme. These findings suggest that NPQ control mechanisms are not universal and we suggest that it may have diverged early in the evolution of different groups of eukaryotic phototrophs.

► Heat dissipation in the brown alga Macrocystis pyrifera. ► Non-photochemical quenching induction and relaxation in M. pyrifera. ► Heat dissipation in M. pyrifera is associated only with the formation of zeaxanthin. ► Different control of heat dissipation between higher plants and M. pyrifera.

Keywords
Brown algae; Evolution; Macrocystis pyrifera; Non-photochemical quenching; Photoprotection; Xanthophyll cycle
First Page Preview
Photoprotection in the brown alga Macrocystis pyrifera: Evolutionary implications
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 104, Issues 1–2, July–August 2011, Pages 377–385
Authors
, , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us