An Optimized Genetically Encoded Dual Reporter For Simultaneous Ratio Imaging Of Ca2+ And H+ Reveals New Insights Into Ion Signaling In Plants
NEW PHYTOLOGIST(2021)
Abstract
Whereas the role of calcium ions (Ca2+) in plant signaling is well studied, the physiological significance of pH-changes remains largely undefined.Here we developed CapHensor, an optimized dual-reporter for simultaneous Ca2+ and pH ratio-imaging and studied signaling events in pollen tubes (PTs), guard cells (GCs), and mesophyll cells (MCs). Monitoring spatio-temporal relationships between membrane voltage, Ca2+- and pH-dynamics revealed interconnections previously not described.In tobacco PTs, we demonstrated Ca2+-dynamics lag behind pH-dynamics during oscillatory growth, and pH correlates more with growth than Ca2+. In GCs, we demonstrated abscisic acid (ABA) to initiate stomatal closure via rapid cytosolic alkalization followed by Ca2+ elevation. Preventing the alkalization blocked GC ABA-responses and even opened stomata in the presence of ABA, disclosing an important pH-dependent GC signaling node. In MCs, a flg22-induced membrane depolarization preceded Ca2+-increases and cytosolic acidification by c. 2 min, suggesting a Ca2+/pH-independent early pathogen signaling step. Imaging Ca2+ and pH resolved similar cytosol and nuclear signals and demonstrated flg22, but not ABA and hydrogen peroxide to initiate rapid membrane voltage-, Ca2+- and pH-responses.We propose close interrelation in Ca2+- and pH-signaling that is cell type- and stimulus-specific and the pH having crucial roles in regulating PT growth and stomata movement.
MoreTranslated text
Key words
abscisic acid (ABA), calcium, flg22, guard cells, imaging, ion signaling, pH, pollen tube
AI Read Science
Must-Reading Tree
Example
![](https://originalfileserver.aminer.cn/sys/aminer/pubs/mrt_preview.jpeg)
Generate MRT to find the research sequence of this paper
Chat Paper
Summary is being generated by the instructions you defined