title: Regulation of the calcium-sensing receptor in both stomatal movement and photosynthetic electron transport is crucial for water use efficiency and drought tolerance in Arabidopsis.
abstract: Production per amount of water used (water use efficiency, WUE) is closely correlated with drought tolerance. Although stomatal aperture can regulate WUE, the underlying molecular mechanisms are still unclear. Previous reports revealed that stomatal closure was inhibited in the calcium-sensing receptor (CAS) antisense line of Arabidopsis (CASas). Here it is shown that decreased drought tolerance and WUE of CASas was associated with higher stomatal conductance due to improper regulation of stomatal aperture, rather than any change of stomatal density. CASas plants also had a lower CO2 assimilation rate that was attributed to a lower photosynthetic electron transport rate, leading to higher chlorophyll fluorescence. Gene co-expression combined with analyses of chlorophyll content and transcription levels of photosynthesis-related genes indicate that CAS is involved in the formation of the photosynthetic electron transport system. These data suggest that CAS regulates transpiration and optimizes photosynthesis by playing important roles in stomatal movement and formation of photosynthetic electron transport, thereby regulating WUE and drought tolerance.
authors.affiliation: Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, China.
authors.forename: Wen-Hua
authors.initials: WH
authors.lastname: Wang
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.forename: Ting-Wu
authors.initials: TW
authors.lastname: Liu
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.forename: Ai-Dong
authors.initials: AD
authors.lastname: Han
authors.forename: Martin
authors.initials: M
authors.lastname: Simon
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Dong
authors.forename: Jun-Xian
authors.initials: JX
authors.lastname: He
authors.forename: Hai-Lei
authors.initials: HL
authors.lastname: Zheng
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D003681:Dehydration; D055864:Droughts; D004579:Electron Transport; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D010788:Photosynthesis / Q000502:physiology; D019441:Plant Epidermis / Q000235:genetics / Q000502:physiology; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology; D054046:Plant Stomata / Q000235:genetics / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology; D013997:Time Factors; D014867:Water / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; C532740:CAS protein, Arabidopsis; D002135:Calcium-Binding Proteins; D014867:Water; D002734:Chlorophyll; D002245:Carbon Dioxide; D002118:Calcium
keywords: Arabidopsis; calcium-sensing receptor; drought tolerance; stomatal movements; water use efficiency.