title: Evolutionary History of the Enzymes Involved in the Calvin-Benson Cycle in Euglenids.
abstract: Euglenids are an ancient lineage that may have existed as early as 2 billion years ago. A mere 65 years ago, Melvin Calvin and Andrew A. Benson performed experiments on Euglena gracilis and elucidated the series of reactions by which carbon was fixed and reduced during photosynthesis. However, the evolutionary history of this pathway (Calvin-Benson cycle) in euglenids was more complex than Calvin and Benson could have imagined. The chloroplast present today in euglenophytes arose from a secondary endosymbiosis between a phagotrophic euglenid and a prasinophyte green alga. A long period of evolutionary time existed before this secondary endosymbiotic event took place, which allowed for other endosymbiotic events or gene transfers to occur prior to the establishment of the green chloroplast. This research revealed the evolutionary history of the major enzymes of the Calvin-Benson cycle throughout the euglenid lineage and showed that the majority of genes for Calvin-Benson cycle enzymes shared an ancestry with red algae and/or chromophytes suggesting they may have been transferred to the nucleus prior to the acquisition of the green chloroplast.
authors.affiliation: Department of Plant Biology, Michigan State University, 612 Wilson Road, 166 Plant Biology Labs, East Lansing, Michigan, 48824.
authors.forename: Chelsea M
authors.initials: CM
authors.lastname: Markunas
authors.affiliation: Department of Plant Biology, Michigan State University, 612 Wilson Road, 166 Plant Biology Labs, East Lansing, Michigan, 48824.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Triemer
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000145:classification / Q000235:genetics / Q000378:metabolism; D001499:Bayes Theorem; D005075:Biological Evolution; D000460:Chlorophyta / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D002736:Chloroplasts / Q000235:genetics; D004798:Enzymes / Q000145:classification / Q000235:genetics / Q000378:metabolism; D016822:Euglenida / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D006597:Fructose-Bisphosphatase / Q000145:classification / Q000235:genetics / Q000378:metabolism; D022761:Gene Transfer, Horizontal; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000145:classification / Q000235:genetics / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000145:classification / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D000461:Rhodophyta / Q000201:enzymology; D013559:Symbiosis; D014305:Triose-Phosphate Isomerase / Q000145:classification / Q000235:genetics / Q000378:metabolism
chemical_list: D004798:Enzymes; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D006597:Fructose-Bisphosphatase; D010744:Phosphoric Monoester Hydrolases; C022627:sedoheptulose-bisphosphatase; D019747:Aldose-Ketose Isomerases; D014305:Triose-Phosphate Isomerase; C022548:ribosephosphate isomerase
keywords: chloroplast genomics; endosymbiosis; fructose 1,6-bisphosphatase; genomics; glyceraldehyde-3-phosphate dehydrogenase; horizontal gene transfer; ribose-5-phosphate isomerase; sedoheptulose-1,7-bisphosphatase; triosephosphate isomerase