title: Self-reporting Arabidopsis expressing pH and [Ca2+] indicators unveil ion dynamics in the cytoplasm and in the apoplast under abiotic stress.
abstract: For noninvasive in vivo measurements of intra- and extracellular ion concentrations, we produced transgenic Arabidopsis expressing pH and calcium indicators in the cytoplasm and in the apoplast. Ratiometric pH-sensitive derivatives of the green fluorescent protein (At-pHluorins) were used as pH indicators. For measurements of calcium ([Ca(2+)]), luminescent aequorin variants were expressed in fusion with pHluorins. An Arabidopsis chitinase signal sequence was used to deliver the indicator complex to the apoplast. Responses of pH and [Ca(2+)] in the apoplast and in the cytoplasm were studied under salt and "drought" (mannitol) stress. Results are discussed in the frame of ion flux, regulation, and signaling. They suggest that osmotic stress and salt stress are differently sensed, compiled, and processed in plant cells.
authors.affiliation: Institut für Pflanzenernährung und Bodenkunde, Christian-Albrechts-Universität, D-24098 Kiel, Germany.
authors.forename: Dongjie
authors.initials: D
authors.lastname: Gao
authors.forename: Marc R
authors.initials: MR
authors.lastname: Knight
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Trewavas
authors.forename: Burkhard
authors.initials: B
authors.lastname: Sattelmacher
authors.forename: Christoph
authors.initials: C
authors.lastname: Plieth
mesh_terms: D000331:Aequorin / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D003080:Cold Temperature; D003593:Cytoplasm / Q000378:metabolism; D005453:Fluorescence; D049452:Green Fluorescent Proteins; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements; D008164:Luminescent Proteins / Q000235:genetics; D009997:Osmotic Pressure; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012965:Sodium Chloride
chemical_list: D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D012965:Sodium Chloride; D000331:Aequorin; D002118:Calcium