title: Rubisco catalytic properties optimized for present and future climatic conditions.
abstract: Because of its catalytic inefficiencies, Rubisco is the most obvious target for improvement to enhance the photosynthetic capacity of plants. Two hypotheses are tested in the present work: (1) existing Rubiscos have optimal kinetic properties to maximize photosynthetic carbon assimilation in existing higher plants; (2) current knowledge allows proposal of changes to kinetic properties to make Rubiscos more suited to changed conditions in chloroplasts that are likely to occur with climate change. The catalytic mechanism of Rubisco results in higher catalytic rates of carboxylation being associated with decreased affinity for CO2, so that selection for different environments involves a trade-off between these two properties. The simulations performed in this study confirm that the optimality of Rubisco kinetics depends on the species and the environmental conditions. In particular, environmental drivers affecting the CO2 availability for carboxylation (Cc) or directly shifting the photosynthetic limitations between Rubisco and RuBP regeneration determine to what extend Rubisco kinetics are optimally suited to maximize CO2 assimilation rate. In general, modeled values for optimal kinetic reflect the predominant environmental conditions currently encountered by the species in the field. Under future climatic conditions, photosynthetic CO2 assimilation will be limited by RuBP-regeneration, especially in the absence of water stress, the largest rise in [CO2] and the lowest increases in temperature. Under these conditions, the model predicts that optimal Rubisco should have high Sc/o and low kcat(c).
authors.affiliation: Research Group in Plant Biology under Mediterranean Conditions, Department of Biology, Universitat de les Illes Balears, Carretera de Valldemossa km 7.5, 07122 Palma, Illes Balears, Spain. Electronic address: jeroni.galmes@uib.cat.
authors.forename: J
authors.initials: J
authors.lastname: Galmés
authors.affiliation: Research Group in Plant Biology under Mediterranean Conditions, Department of Biology, Universitat de les Illes Balears, Carretera de Valldemossa km 7.5, 07122 Palma, Illes Balears, Spain.
authors.forename: M À
authors.initials: MÀ
authors.lastname: Conesa
authors.affiliation: Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes 10, 41012 Sevilla, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Díaz-Espejo
authors.affiliation: Computational Biology and Bioinformatics Research Group, Department of Mathematics and Computer Science, Universitat de les Illes Balears, Carretera de Valldemossa km 7.5, 07122 Palma, Illes Balears, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Mir
authors.affiliation: Research Group in Plant Biology under Mediterranean Conditions, Department of Biology, Universitat de les Illes Balears, Carretera de Valldemossa km 7.5, 07122 Palma, Illes Balears, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Perdomo
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
authors.forename: U
authors.initials: U
authors.lastname: Niinemets
authors.affiliation: Research Group in Plant Biology under Mediterranean Conditions, Department of Biology, Universitat de les Illes Balears, Carretera de Valldemossa km 7.5, 07122 Palma, Illes Balears, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Flexas
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D057231:Climate Change; D004777:Environment; D007700:Kinetics; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*; D013696:Temperature
chemical_list: D002245:Carbon Dioxide; D012273:Ribulose-Bisphosphate Carboxylase; D010100:Oxygen
keywords: Climate change; Crops productivity; Photosynthesis; Rubisco; Water stress