2.6 Electrophoretic mobility shift assay
The electrophoretic mobility shift assay (EMSA) was performed as described (Hong et al. , 2012; He et al. , 2021). Recombinant His-OsPHR2 proteins were induced and purified as described (Liu et al. , 2010; Lv et al. , 2014). The promoter fragment containing GNATATNC was labeled with biotin at its 5’ end. The LightShift Chemiluminescent EMSA Kit (Pierce, USA) was used to perform the experiment according to the manufacturer’s instructions. Fluorescence was detected using enhanced chemiluminescence substrate with the ChemiDocTM MP imaging system (Bio-Rad,). Probe sequences and primers are listed in Table S1.