Self-reporting Arabidopsis expressing pH and [Ca2+] indicators unveil ion dynamics in the cytoplasm and in the apoplast under abiotic stress.
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.
Gao
Dongjie
D
Institut für Pflanzenernährung und Bodenkunde, Christian-Albrechts-Universität, D-24098 Kiel, Germany.
Knight
Marc R
MR
Trewavas
Anthony J
AJ
Sattelmacher
Burkhard
B
Plieth
Christoph
C
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
D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D012965:Sodium Chloride; D000331:Aequorin; D002118:Calcium