Figure 10.

Potassium Level Controls ARF2 Phosphorylation Status and HAK5 Expression.

(A) ARF2 phosphorylation status in wild-type plants under different K⁺ conditions. arf2-7/ProARF2:ARF2-Flag (COM1) transgenic plants were germinated and grown on K⁺-sufficient medium (1 mM K⁺) for 5 d and then transferred to low-K⁺ medium (10 μM K⁺) for 6 h. After that, the seedlings were transferred back to K⁺-sufficient medium (1 mM K⁺) for 4 and 6 h. Total proteins of the plants at different time points were extracted. ARF2 proteins were immunoprecipitated using anti-Flag mAb agarose. Phosphorylated ARF2 proteins were detected by immunoblotting (IB) using biotinylated Phos-tag. CIAP can dephosphorylate ARF2, which was used as a control.

(B) HAK5 expression in wild-type plants and arf2 mutants under different K⁺ conditions described in (A). Total RNA of the plants at different time points was extracted and used for RT-qPCR analyses. Transcript level of HAK5 was quantified.