Figure 7.

Sucrose uptake by ZmSUGCAR1 independent of the extracellular K⁺. A, ZmSUGCAR1 mediates sucrose uptake independent of extracellular K⁺ using ¹⁴C-labeled sugar uptake assay in oocytes. Oocytes expressing ZmSUT1 were used as positive controls for sucrose uptake. Oocytes injected with water were used as the negative controls. B, ZmSUGCAR1 mediates proton influx induced by sucrose independent of the extracellular K⁺ using NMT in the oocytes at pH 5.5. Oocytes expressing ZmSUT1 were used as the positive control for the sucrose-mediated H⁺ influx, and oocytes injected with water were used as the negative control. C, I/V relationships of steady-state currents for ZmSUGCAR1 triggered by sucrose, independent of extracellular K⁺, according to the whole-cell patch-clamp recordings in HEK293T cells. D, ZmSUGCAR1-mediated currents in HEK293T cells at −180 mV. The cells transfected with empty vector (EGFP) were used as negative control; data are presented as mean ± se, and n indicated biologically independent cells in (C) and (D). E, Whole-cell patch-clamp recordings in HEK293T cells expressing ZmSUGCAR1. P < 0.05 indicated significant differences.