title: Absence of OsβCA1 causes a CO2deficit and affects leaf photosynthesis and the stomatal response to CO2in rice.
abstract: Plants always adjust the opening of stomatal pores to adapt to the environment, for example CO2concentration ([CO2]), humidity and temperature. Low [CO2] will trigger the opening of stomatal pores to absorb extra CO2. However, little is known about how CO2supply affects the carbon fixation and opening of stomatal pores in rice. Here, a chloroplast-located gene coding for β-carbonic anhydrase (βCA) was found to be involved in carbon assimilation and the CO2-mediated stomatal pore response in rice. OsβCA1 was constitutively expressed in all tissues and its transcripts were induced by high [CO2] in leaves. Both T-DNA mutant and RNA interference lines showed phenotypes of lower biomass and CA activities. Knockout of OsβCA1 obviously decreased photosynthetic capacity, as demonstrated by the increased CO2compensation point and decreased light saturation point in the mutant, while knockout increased the opening ratio of stomatal pores and the rate of water loss. Moreover, the mutant showed a delayed response to low [CO2], and stomatal pores could not be closed to the same degree as those of wild type even though the stomatal pores could rapidly respond to high [CO2]. Genome-wide gene expression analysis via RNA sequencing demonstrated that the transcript abundance of genes related to Rubisco, photosystem compounds and the opening of stomatal pores was globally upregulated in the mutant. Taken together, the inadequate CO2supply caused by the absence of OsβCA1 reduces photosynthetic efficiency, triggers the opening of stomatal pores and finally decreases their sensitivity to CO2fluctuation.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China.|College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Taiyu
authors.initials: T
authors.lastname: Chen
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Wu
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China.
authors.forename: Jiemin
authors.initials: J
authors.lastname: Wu
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Fan
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China.
authors.forename: Xianghua
authors.initials: X
authors.lastname: Li
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan, 430070, China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Lin
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D002256:Carbonic Anhydrases / Q000378:metabolism; D012275:Oryza / Q000378:metabolism*; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D054046:Plant Stomata / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D002245:Carbon Dioxide; D002256:Carbonic Anhydrases
keywords: 
  Oryza sativa
  ; CO2 assimilation; CO2 response; RNA-seq; carbonic anhydrase; gene family