Unique Regulation of the Calvin Cycle in the Ultrasmall Green Alga Ostreococcus
Glyceraldehyde-3-phosphate dehydrogenase (GapAB) and CP12 are two major players in controlling the inactivation of the Calvin cycle in land plants at night. GapB originated from a GapA gene duplication and differs from GapA by the presence of a specific C-terminal extension that was recruited from CP12. While GapA and CP12 are assumed to be generally present in the Plantae (glaucophytes, red and green algae, and plants), up to now GapB was exclusively found in Streptophyta, including the enigmatic green alga Mesostigma viride. However, here we show that two closely related prasinophycean green algae, Ostreococcus tauri and Ostreococcus lucimarinus, also possess a GapB gene, while CP12 is missing. This remarkable finding either antedates the GapA/B gene duplication or indicates a lateral recruitment. Moreover, Ostreococcus is the first case where the crucial CP12 function may be completely replaced by GapB-mediated GapA/B aggregation.
KeywordsOstreococcus tauri Ostreococcus lucimarinus Plant evolution Glyceraldehyde-3-phosphate dehydrogenase CP12 Calvin cycle
The authors would like to thank Igor Grigoriev, Brian Palenik, and the JGI for the prior access to the Ostreococcus lucimarinus data. S.R. is indebted to the Institute for the Promotion of Innovation by Science and Technology in Flanders for a predoctoral fellowship. The authors also want to thank two anonymous reviewers for careful reading of the manuscript and constructive criticisms.
- Armbrust EV, Berges JA, Bowler C, Green BR, Martinez D, Putnam NH, Zhou S, Allen AE, Apt KE, Bechner M, Brzezinski MA, Chaal BK, Chiovitti A, Davis AK, Demarest MS, Detter JC, Glavina T, Goodstein D, Hadi MZ, Hellsten U, Hildebrand M, Jenkins BD, Jurka J, Kapitonov VV, Kroger N, Lau WW, Lane TW, Larimer FW, Lippmeier JC, Lucas S, Medina M, Montsant A, Obornik M, Parker MS, Palenik B, Pazour GJ, Richardson PM, Rynearson TA, Saito MA, Schwartz DC, Thamatrakoln K, Valentin K, Vardi A, Wilkerson FP, Rokhsar DS (2004) The genome of the diatom Thalassiosira pseudonana: ecology, evolution, and metabolism. Science 306:79–86PubMedCrossRefGoogle Scholar
- Derelle E, Ferraz C, Rombauts S, Rouze P, Worden AZ, Robbens S, Partensky F, Degroeve S, Echeynie S, Cooke R, Saeys Y, Wuyts J, Jabbari K, Bowler C, Panaud O, Piegu B, Ball SG, Ral JP, Bouget FY, Piganeau G, De Baets B, Picard A, Delseny M, Demaille J, Van de Peer Y, Moreau H (2006) From the cover: genome analysis of the smallest free-living eukaryote Ostreococcus tauri unveils many unique features. Proc Natl Acad Sci USA 103:11647–11652PubMedCrossRefGoogle Scholar
- Graham LE, Wilcox LW (2000) Green algae I-introduction and prasinophyceans. In: Graham LE, Wilcox LW (eds.). Algae, Upper Saddle River, Prentice Hall, pp 397–419Google Scholar