Evolution of an atypical de-epoxidase for photoprotection in the green lineage.
Plants, algae and cyanobacteria need to regulate photosynthetic light harvesting in response to the constantly changing light environment. Rapid adjustments are required to maintain fitness because of a trade-off between efficient solar energy conversion and photoprotection. The xanthophyll cycle, in which the carotenoid pigment violaxanthin is reversibly converted into zeaxanthin, is ubiquitous among green algae and plants and is necessary for the regulation of light harvesting, protection from oxidative stress and adaptation to different light conditions(1,2). Violaxanthin de-epoxidase (VDE) is the key enzyme responsible for zeaxanthin synthesis from violaxanthin under excess light. Here we show that the Chlorophycean VDE (CVDE) gene from the model green alga Chlamydomonas reinhardtii encodes an atypical VDE. This protein is not homologous to the VDE found in plants and is instead related to a lycopene cyclase from photosynthetic bacteria(3). Unlike the plant-type VDE that is located in the thylakoid lumen, the Chlamydomonas CVDE protein is located on the stromal side of the thylakoid membrane. Phylogenetic analysis suggests that CVDE evolved from an ancient de-epoxidase that was present in the common ancestor of green algae and plants, providing evidence of unexpected diversity in photoprotection in the green lineage.
Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3102, USA.|Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Zhirong
Z
Li
Department of Biology, Colorado State University, Fort Collins, Colorado 80523-1878, USA.
Graham
0000-0002-3590-7820
G
Peers
Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3102, USA.
Rachel M
RM
Dent
Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3102, USA.
Yong
Y
Bai
Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3102, USA.
Scarlett Y
SY
Yang
Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3102, USA.
Wiebke
W
Apel
Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3102, USA.
Lauriebeth
L
Leonelli
Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3102, USA.|Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Krishna K
KK
Niyogi
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D019143:Evolution, Molecular; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010788:Photosynthesis; D010802:Phylogeny; D020524:Thylakoids / Q000378:metabolism
D001426:Bacterial Proteins; D010088:Oxidoreductases; C023290:violaxanthin de-epoxidase