title: Whole-plant growth and N utilization in transgenic rice plants with increased or decreased Rubisco content under different CO2 partial pressures.
abstract: Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) strongly limits photosynthesis at lower CO2 concentration [CO2] whereas [corrected] Rubisco limitation is cancelled by elevated [CO2]. Therefore, increase or reduction in Rubisco content by transformation with a sense or an antisense RBCS construct are expected to alter the biomass production under different CO2 levels. RBCS-sense (125% Rubisco of wild-type) and -antisense (35% Rubisco of wild-type) rice (Oryza sativa L.) plants were grown for 63 days at three different CO2 levels: low [CO2] (28 Pa), normal [CO2] (40 Pa) and elevated [CO2] (120 Pa). The biomass of RBCS-sense plants was 32% and 15% greater at low [CO2] and normal [CO2] than that of the wild-type plants, respectively, but did not differ at elevated [CO2]. Conversely, the biomass of RBCS-antisense plants was the smallest at low [CO2]. Thus, overproduction of Rubisco was effective for biomass production at low [CO2]. Greater biomass production at low [CO2] in RBCS-sense plants was caused by an increase in the net assimilation rate, and associated with an increase in the amount of N uptake. Furthermore, Rubisco overproduction in RBCS-sense plants was also promoted at low [CO2]. Although it seems that low [CO2]-growth additionally stimulates the effect of RBCS overexpression, such a phenomenon observed at low [CO2] was mediated through an increase in total leaf N content. Thus, the dependence of the growth improvement in RBCS-sense rice on growth [CO2] was closely related to the degree of Rubisco overproduction which was accompanied not only by leaf N content but also by whole plant N content.
authors.affiliation: Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555 Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Sudo
authors.affiliation: Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555 Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555 Japan CREST, JST, Gobancho, Chiyoda-ku, Tokyo, 102-0076 Japan makino@biochem.tohoku.ac.jp.
authors.forename: Amane
authors.initials: A
authors.lastname: Makino
mesh_terms: D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism; D018525:Germination; D009584:Nitrogen / Q000378:metabolism*; D012275:Oryza / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D030821:Plants, Genetically Modified; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics / Q000378:metabolism*; D013213:Starch / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D002245:Carbon Dioxide; D013395:Sucrose; D013213:Starch; D012273:Ribulose-Bisphosphate Carboxylase; D009584:Nitrogen
keywords: Biomass; Low and elevated [CO2]; Nitrogen; Oryza sativa; RBCS; Rubisco overproduction