title: Photorespiration connects C3 and C4 photosynthesis.
abstract: C4 plants evolved independently more than 60 times from C3 ancestors. C4 photosynthesis is a complex trait and its evolution from the ancestral C3 photosynthetic pathway involved the modification of the leaf anatomy and the leaf physiology accompanied by changes in the expression of thousands of genes. Under high temperature, high light, and the current CO2 concentration in the atmosphere, the C4 pathway is more efficient than C3 photosynthesis because it increases the CO2 concentration around the major CO2 fixating enzyme Rubisco. The oxygenase reaction and, accordingly, photorespiration are largely suppressed. In the present review we describe a scenario for C4 evolution that not only includes the avoidance of photorespiration as the major driving force for C4 evolution but also highlights the relevance of changes in the expression of photorespiratory genes in inducing and establishing important phases on the path from C3 to C4.
authors.affiliation: Institute of Plant Biochemistry, Universitätsstrasse 1, Heinrich-Heine-University, 40225 Düsseldorf, Germany Cluster of Excellence on Plant Sciences (CEPLAS) "From Complex Traits towards Synthetic Modules", 40225 Düsseldorf, Germany Present address: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, 06466 Stadt Seeland, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bräutigam
authors.affiliation: Institute of Plant Molecular and Developmental Biology, Universitätsstrasse 1, Heinrich- Heine-University, 40225 Düsseldorf, Germany gowik@uni-duesseldorf.de.
authors.forename: Udo
authors.initials: U
authors.lastname: Gowik
mesh_terms: D005075:Biological Evolution; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000378:metabolism / Q000502:physiology; D018521:Plant Physiological Phenomena; D010944:Plants / Q000378:metabolism
chemical_list: D002245:Carbon Dioxide; D002244:Carbon
keywords: C4 photosynthesis; CO2 fixation; evolution; photorespiration