title: New evidence for grain specific C4 photosynthesis in wheat.
abstract: The C4 photosynthetic pathway evolved to allow efficient CO2 capture by plants where effective carbon supply may be limiting as in hot or dry environments, explaining the high growth rates of C4 plants such as maize. Important crops such as wheat and rice are C3 plants resulting in efforts to engineer them to use the C4 pathway. Here we show the presence of a C4 photosynthetic pathway in the developing wheat grain that is absent in the leaves. Genes specific for C4 photosynthesis were identified in the wheat genome and found to be preferentially expressed in the photosynthetic pericarp tissue (cross- and tube-cell layers) of the wheat caryopsis. The chloroplasts exhibit dimorphism that corresponds to chloroplasts of mesophyll- and bundle sheath-cells in leaves of classical C4 plants. Breeding to optimize the relative contributions of C3 and C4 photosynthesis may adapt wheat to climate change, contributing to wheat food security.
authors.affiliation: Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane QLD 4072, Australia.|Division of Genomic Resources, ICAR-National Bureau of Plant Genetic Resources, New Delhi-110012, India.
authors.forename: Parimalan
authors.initials: P
authors.lastname: Rangan
authors.affiliation: Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane QLD 4072, Australia.
authors.forename: Agnelo
authors.initials: A
authors.lastname: Furtado
authors.affiliation: Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane QLD 4072, Australia.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Henry
mesh_terms: D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000378:metabolism; D057231:Climate Change; D019143:Evolution, Molecular; D005523:Food Supply; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D005838:Genotype; D010788:Photosynthesis / Q000235:genetics; D000069600:Plant Breeding; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014908:Triticum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide