The Role Of14-3-3Protein In EATP Promoted Stomal Opening In Arabidopsis Thaliana

Stomatal are important gateway which regulate gas and water exchange between plantand environment. Stomata is surrounded by a pair of guard cells. The guard cells are sensitiveto environment. When they were stimulated by signal molecules, they regulate stomatalaperture by regulating water potential in cells.Our previous results showed that eATP promoted stomatal opening in Arabidopsis as asignal molecular. In eATP-promoted stomatal opening, plasma membrane H+-ATPase playeda key role.14-3-3proteins bind to the C-terminus autoinhibitory domain of the H~+-ATPase,enhance its pumping activity and promote stomatal opening. In order to verify the role of14-3-3protein in eATP signal transduction and the role of various14-3-3proteins inregulating plasma membrane H+-ATPase participated stomatal opening,14-3-3isoforms (grf1,grf2, grf5and grf6) which related with plasma membrane H+-ATPase and stomatal openingwere used as materials, epidermal strip bioassay and the Scanning Ion-selective ElectrodeTecnique (SIET) were used as main methods.The results indicate that in epidermal strains of in wild type added ATP promotedstomatal opening both in light and darkness. The response of stomata movement of grf1andgrf5to ATP stimulation was weaker than that in wt. Response of stomatal movement of grf2and grf6was similar to that in wt. The results suggest that14-3-3protein grf1and grf5areinvolved in eATP promoted stomatal opening, while grf2and grf6are not involved in thisprocess.In order to explore the physiological mechanism of eATP promoted stomatal opening, wedetected H+fluxes in Arabidopsis guard cells by using the Scanning Ion-selective ElectrodeTecnique (SIET). The results indicated that in wild type, grf1and grf2, added ATP promotedH+efflux remarkably. Null mutants and wt’s H+efflux trend induced by eATP was almostlythe same.The trend was up to maxmum then decreased. The duration of H+efflux in mutantswas longer than wt. The total of H+efflux in wt was significantly weaker in14-3-3proteinnull mutants (grf1and grf5), suggesting that grf1and grf5may be not involved in the processof H+efflux. Whether14-3-3protein null mutants (grf1and grf5) take part in eATP promotingstomatal opening or not, we need do more deeper research.